NOKIA

NOKIA=====Nokia is a small town on the banks of the Nokianvirta (Kokemenjoki) River in the region of Pirkanmaa and the province of Western Finland, some 15 km west of Tampere. As of October 2006, it has a population of 29,685.The name of the town of Nokia originated from the river which flowed through the town. The river itself, Nokianvirta, was named after the old Finnish word originally meaning sable, later pine marten. A species of this small, black-furred predatory animal was once found in the region, but it is now extinct.

Industrial history==================Telecommunication giant Nokia was established in Nokia (hence the name.) The now billion-dollar company was founded by Fredrik Idestam in 1865 as a pulp mill for manufacturing paper. Finnish Rubber Works Ltd (Suomen Gummitehdas Osakeyhti) (founded 1898) set up a factory inNokia in 1904. These two companies and Finnish Cable Works Ltd ("Suomen kaapelitehdas Oy") were fusioned 1967 forming Nokia Corporation. Different branches of this conglomerate were split into several companies or sold away around 1990. The rubber works still operates in Nokia as Nokian Tyres and the paper mill as Georgia-Pacific Finland Oy. The telecommunication company Nokia no longer has any operations in the town of Nokia

Nokia was listed as the 20th most admirable company worldwide in Fortune's list of 2006 (1st in network communications, 4th non-US company).

NOKIA FONT==========The Nokia corporate font (typeface) is the AgfaMonotype Nokia Sans font, originally designed by Eric Spiekermann. Previously in advertising and in its mobile phone User's Guides Nokia mostly used the Agfa Rotis Sans font.

NOKIA TUNE=========The Nokia tune is the melody used in all Nokia mobile phones as the default ring tone. Nokia also uses it in advertising. The tune is an excerpt of a few bars from Francisco Trrega's Gran Vals; Nokia nevertheless claims it as a sound trademark.

The ringtone "Nokia tune" is actually based on a 19th century guitar work named "Gran Vals" by Spanish musician Francisco Trrega. The Nokia Tune was originally named "Grande Valse" on Nokia phones but was changed to "Nokia Tune" around 1998 when it became so well known that people referred to it as the "Nokia Tune."

The Nokia tune was sampled in the 1999 song "I Wanna 1-2-1 With You" by the Solid Gold Chartbusters.

The year 1993 marked the beginning of the Nokia tune, starting with the launch of Nokia's 2100 series. The new phone was more advanced than previous ones with 27 pre installed ringtones. Anssi Vanjoki (today Nokia's Executive Vice President and General Manager of Multimedia) suggested that one of the pre installed tones could be Nokia's own ringtone. His proposal for the "Nokia tune" was Francisco Trrega's (1852-1909) "Gran Vals" that was currently used on Nokia TV-commercials

NOKIA SMS TONE=================The "Special" tone available to users of Nokia phones when receiving SMS (text messages) is actually Morse code for "SMS". Similarly, the "Ascending" SMS tone is Morse code for "Connecting People,"Nokia's slogan. The "Standard" SMS tone is Morse code for "M" (Message).

NOKIA GSM , THE VERY FIRST COMERCIAL CALL=========================================The world's first commercial GSM call was made in 1991 in Helsinki over a Nokia-supplied network, by Prime Minister of Finland Harri Holkeri, using a Nokia phone.How to solve charging problem

Two sections in charging

1. input section

2.output section

so all charging problems comes under this two section "input problem or output problem.

how to find which section is fault ?

input problem identify

if put charger mobile wil not response or mobile wil not shows indication on display means input problem

output problem identify

if put charger mobile wil shows Not charging on display or charging wil going but battery wil not fil and when put charger light wil blink but charging wil not run these identify are output problem.

wait for update

Overview Global System Mobile Communications

History of GSMDuring the early 1980s, analog cellular telephone systems were experiencing rapid growth in Europe, particularly in Scandinavia and the United Kingdom, but also in France and Germany. Each country developed its own system, which was incompatible with everyone else's in equipment and operation. This was an undesirable situation, because not only was the mobile equipment limited to operation within national boundaries, which in a unified Europe were increasingly unimportant, but there wasalso a very limited market for each type of equipment, so economies of scale and the subsequent savings could not be realized.The Europeans realized this early on, and in 1982 the Conference of European Posts and Telegraphs (CEPT) formed a study group called the Groupe Spcial Mobile (GSM) to study and develop a pan-European public land mobile system. The proposed system had to meet certain criteria: Good subjective speech quality Low terminal and service cost Support for international roaming Ability to support handheld terminals Support for range of new services and facilities Spectral efficiency ISDN compatibilityIn 1989, GSM responsibility was transferred to the European Telecommunication Standards Institute (ETSI), and phase I of the GSM specifications were published in 1990. Commercial service was started in mid-1991, and by 1993 there were 36 GSM networks in 22 countries [6]. Although standardized in Europe, GSM is not only a European standard. Over 200 GSM networks (including DCS1800 and PCS1900) are operational in 110 countries around the world. In the beginning of 1994, there were 1.3 million subscribers worldwide [18], which had grown to more than 55 million by October 1997. With North America making a delayed entry into the GSM field with a derivative of GSM called PCS1900, GSM systems exist on every continent, and the acronym GSM now aptly stands for Global System forMobile communications.The developers of GSM chose an unproven (at the time) digital system, as opposed to the then-standard analog cellular systems like AMPS in the United States and TACS in the United Kingdom. They had faith that advancements in compression algorithms and digital signal processors would allow the fulfillment of the original criteria and the continual improvement of the system in terms of quality and cost. The over 8000 pages of GSM recommendations try to allow flexibility and competitive innovation among suppliers, but provide enough

standardization to guarantee proper interworking between the components of the system. This is done by providing functional and interface descriptions for each of the functional entities defined in the system.Services provided by GSMFrom the beginning, the planners of GSM wanted ISDN compatibility in terms of the services offered and the control signaling used. However, radio transmission limitations, in terms of bandwidth and cost, do not allow the standard ISDN B-channel bit rate of 64 kbps to be practically achieved.Using the ITU-T definitions, telecommunication services can be divided into bearer services, tele services, and supplementary services. The most basic tele service supported by GSM is telephony. As with all other communications, speech is digitally encoded and transmitted through the GSM network as a digital stream. There isalso an emergency service, where the nearest emergency-service provider is notified by dialing three digits (similar to 911).A variety of data services is offered. GSM users can send and receive data, at rates up to 9600 bps, to users on POTS (Plain Old Telephone Service), ISDN, Packet Switched Public Data Networks, and Circuit Switched Public Data Networks using a variety of access methods and protocols, such as X.25 or X.32. Since GSM is a digital network, a modem is not required between the user and GSM network, although an audio modem is required inside the GSM network to interwork with POTS.Other data services include Group 3 facsimile, as described in ITU-T recommendation T.30, which is supported by use of an appropriate fax adaptor. A unique feature of GSM, not found in older analog systems, is the Short Message Service (SMS). SMS is a bidirectional service for short alphanumeric (up to 160 bytes) messages. Messages are transported in a store-and-forward fashion. For point-to-point SMS, a message can be sent to another subscriber to the service, and an acknowledgement of receipt is provided to the sender. SMS canalso be used in a cell-broadcast mode, for sending messages such as traffic updates or news updates. Messages can also be stored in the SIM card for later retrieval [2].Supplementary services are provided on top of tele services or bearer services. In the current (Phase I) specifications, they include several forms of call forward (such as call forwarding when the mobile subscriber is unreachable by the network), and call barring of outgoing or incoming calls, for example when roaming in another country. Many additional supplementary services will be provided in the Phase 2 specifications, such as caller identification, call waiting, multi-party conversations.

key for authentication, and other information. The IMEI and the IMSI are independent, thereby allowing personal mobility. The SIM card may be protected against unauthorized use by a password or personal identity number.Base Station SubsystemThe Base Station Subsystem is composed of two parts, the Base Transceiver Station (BTS) and the Base Station Controller (BSC). These communicate across the standardized Abis interface, allowing (as in the rest of the system) operation between components made by different suppliers.The Base Transceiver Station houses the radio transceivers that define a cell and handles the radio-link protocols with the Mobile Station. In a large urban area, there will potentially be a large number of BTSs deployed, thus the requirements for a BTS are ruggedness, reliability, portability, and minimum cost.The Base Station Controller manages the radio resources for one or more BTSs. It handles radio-channel setup, frequency hopping, and handovers, as described below. The BSC is the connection between the mobile station and the Mobile service Switching Center (MSC).Network SubsystemThe central component of the Network Subsystem is the Mobile services Switching Center (MSC). It acts like a normal switching node of the PSTN or ISDN, and additionally provides all the functionality needed to handle a mobile subscriber, such as registration, authentication, location updating, handovers, and call routing to a roaming subscriber. These services are provided in conjunction with several functional entities, which together form the Network Subsystem. The MSC provides the connection to the fixed networks (such as the PSTN or ISDN). Signaling between functional entities in the Network Subsystem uses Signaling System Number 7 (SS7), used for trunk signaling in ISDN and widely used in current public networks.The Home Location Register (HLR) and Visitor Location Register (VLR), together with the MSC, provide the call-routing and roaming capabilities of GSM. The HLR contains all the administrative information of each subscriber registered in the corresponding GSM network, along with the current location of the mobile. The location of the mobile is typically in the form of the signaling address of the VLR associated with the mobile station. The actual routing procedure will be described later. There is logically one HLR per GSM network, although it may be implemented as a distributed database.The Visitor Location Register (VLR) contains selected administrative information from the HLR, necessary for call control and provision of the subscribed services, for each mobile currently located in the geographical area controlled by the VLR.Architecture of the GSM networkA GSM network is composed of several functional entities, whose functions and interfaces are specified. Figure 1 shows the layout of a generic GSM network. The GSM network can be divided into three broad parts. The Mobile Station is carried by the subscriber. The Base Station Subsystem controls the radio link with the Mobile Station. The Network Subsystem, the main part of which is the Mobile services Switching Center (MSC), performs the switching of calls between the mobile users, and between mobile and fixed network users. The MSC also handles the mobility management operations. Not shown is the Operations and Maintenance Center, which oversees the proper operation and setup of the network. The Mobile Station and the Base Station Subsystem communicate across the Um interface, also known as the air interface or radio link. The Base Station Subsystem communicates with the Mobile services Switching Center across the A interface.

Figure 1. General architecture of a GSM networkMobile StationThe mobile station (MS) consists of the mobile equipment (the terminal) and a smart card called the Subscriber Identity Module (SIM). The SIM provides personal mobility, so that the user can have access to subscribed services irrespective of a specific terminal. By inserting the SIM card into another GSM terminal, the user is able to receive calls at that terminal, make calls from that terminal, and receive other subscribed services.The mobile equipment is uniquely identified by the International Mobile Equipment Identity (IMEI). The SIM card contains the International Mobile Subscriber Identity (IMSI) used to identify the subscriber to the system, a secret

Although each functional entity can be implemented as an independent unit, all manufacturers of switching equipment to date implement the VLR together with the MSC, so that the geographical area controlled by the MSC corresponds to that controlled by the VLR, thus simplifying the signaling required. Note that the MSC contains no information about particular mobile stations --- this information is stored in the location registers.The other two registers are used for authentication and security purposes. The Equipment Identity Register (EIR) is a database that contains a list of all valid mobile equipment on the network, where each mobile station is identified by its International Mobile Equipment Identity (IMEI). An IMEI is marked as invalid if it has been reported stolen or is not type approved. The Authentication Center (AuC) is a protected database that stores a copy of the secret key stored in each subscriber's SIM card, which is used for authentication and encryption over the radio channel.Radio link aspectsThe International Telecommunication Union (ITU), which manages the international allocation of radio spectrum (among many other functions), allocated the bands 890-915 MHz for the uplink (mobile station to base station) and 935-960 MHz for the downlink (base station to mobile station) for mobile networks in Europe. Since this range was already being used in the early 1980s by the analog systems of the day, the CEPT had the foresight to reserve the top 10 MHz of each band for the GSM network that was still being developed. Eventually, GSM will be allocated the entire 2x25 MHz bandwidth.Multiple access and channel structureSince radio spectrum is a limited resource shared by all users, a method must be devised to divide up the bandwidth among as many users as possible. The method chosen by GSM is a combination of Time- and Frequency-Division Multiple Access (TDMA/FDMA). The FDMA part involves the division by frequency of the (maximum) 25 MHz bandwidth into 124 carrier frequencies spaced 200 kHz apart. One or more carrier frequencies are assigned to each base station. Each of these carrier frequencies is then divided in time, using a TDMA scheme. The fundamental unit of time in this TDMA scheme is called a burst period and it lasts 15/26 ms (or approx. 0.577 ms). Eight burst periods are grouped into a TDMA frame (120/26 ms, or approx. 4.615 ms), which forms the basic unit for the definition of logical channels. One physical channel is one burst period per TDMA frame.Channels are defined by the number and position of their corresponding burst periods. All these definitions are cyclic, and the entire pattern repeats approximately every 3 hours. Channels can be divided into dedicated channels, which are allocated to a mobile station, and common channels, which are used by mobile stations in idle mode.

that dedicated mobiles using the 26-frame multiframe TCH structure can still monitor control channels. The common channels include:Broadcast Control Channel (BCCH)Continually broadcasts, on the downlink, information including base station identity, frequency allocations, and frequency-hopping sequences.Frequency Correction Channel (FCCH) and Synchronization Channel (SCH)Used to synchronies the mobile to the time slot structure of a cell by defining the boundaries of burst periods, and the time slot numbering. Every cell in a GSM network broadcasts exactly one FCCH and one SCH, which are by definition on time slot number 0 (within a TDMA frame).Random Access Channel (RACH)Slotted Aloha channel used by the mobile to request access to the network.Paging Channel (PCH)Used to alert the mobile station of an incoming call.Access Grant Channel (AGCH)Used to allocate an SDCCH to a mobile for signaling (in order to obtain a dedicated channel), following a request on the RACH.Burst structureThere are four different types of bursts used for transmission in GSM [16]. The normal burst is used to carry data and most signaling. It has a total length of 156.25 bits, made up of two 57 bit information bits, a 26 bit training sequence used for equalization, 1 stealing bit for each information block (used for FACCH), 3 tail bits at each end, and an 8.25 bit guard sequence, as shown in Figure 2. The 156.25 bits are transmitted in 0.577 ms, giving a gross bit rate of 270.833 kbps.The F burst, used on the FCCH, and the S burst, used on the SCH, have the same length as a normal burst, but a different internal structure, which differentiates them from normal bursts (thus allowing synchronization). The access burst is shorter than the normal burst, and is used only on the RACH.Speech codingGSM is a digital system, so speech which is inherently analog, has to be digitized. The method employed by ISDN, and by current telephone systems for multiplexing voice lines over high speed trunks and optical fiber lines, is Pulse Coded Modulation (PCM). The output stream from PCM is 64 kbps, too high a rate to be feasible over a radio link. The 64 kbps signal, although simple to implement, contains much redundancy. The GSM group studied several speech coding algorithms on the basis of subjective speech quality and complexity (which is related to cost, processing delay, and power consumption once implemented) before arriving at the choice of a Regular Pulse Excited -- Linear Predictive Coder (RPE--LPC) with a Long Term Predictor loop. Basically,

that dedicated mobiles using the 26-frame multiframe TCH structure can still monitor control channels. The common channels include:Broadcast Control Channel (BCCH)Continually broadcasts, on the downlink, information including base station identity, frequency allocations, and frequency-hopping sequences.Frequency Correction Channel (FCCH) and Synchronization Channel (SCH)Used to synchronies the mobile to the time slot structure of a cell by defining the boundaries of burst periods, and the time slot numbering. Every cell in a GSM network broadcasts exactly one FCCH and one SCH, which are by definition on time slot number 0 (within a TDMA frame).Random Access Channel (RACH)Slotted Aloha channel used by the mobile to request access to the network.Paging Channel (PCH)Used to alert the mobile station of an incoming call.Access Grant Channel (AGCH)Used to allocate an SDCCH to a mobile for signaling (in order to obtain a dedicated channel), following a request on the RACH.Burst structureThere are four different types of bursts used for transmission in GSM [16]. The normal burst is used to carry data and most signaling. It has a total length of 156.25 bits, made up of two 57 bit information bits, a 26 bit training sequence used for equalization, 1 stealing bit for each information block (used for FACCH), 3 tail bits at each end, and an 8.25 bit guard sequence, as shown in Figure 2. The 156.25 bits are transmitted in 0.577 ms, giving a gross bit rate of 270.833 kbps.The F burst, used on the FCCH, and the S burst, used on the SCH, have the same length as a normal burst, but a different internal structure, which differentiates them from normal bursts (thus allowing synchronization). The access burst is shorter than the normal burst, and is used only on the RACH.Speech codingGSM is a digital system, so speech which is inherently analog, has to be digitized. The method employed by ISDN, and by current telephone systems for multiplexing voice lines over high speed trunks and optical fiber lines, is Pulse Coded Modulation (PCM). The output stream from PCM is 64 kbps, too high a rate to be feasible over a radio link. The 64 kbps signal, although simple to implement, contains much redundancy. The GSM group studied several speech coding algorithms on the basis of subjective speech quality and complexity (which is related to cost, processing delay, and power consumption once implemented) before arriving at the choice of a Regular Pulse Excited -- Linear Predictive Coder (RPE--LPC) with a Long Term Predictor loop. Basically,

information from previous samples, which does not change very quickly, is used to predict the current sample. The coefficients of the linear combination of the previous samples, plus an encoded form of the residual, the difference between the predicted and actual sample, represent the signal. Speech is divided into 20 millisecond samples, each of which is encoded as 260 bits, giving a total bit rate of 13 kbps. This is the so-called Full-Rate speech coding. Recently, an Enhanced Full-Rate (EFR) speech coding algorithm has been implemented by some North American GSM1900 operators. This is said to provide improved speech quality using the existing 13 kbps bit rate.Channel coding and modulationBecause of natural and man-made electromagnetic interference, the encoded speech or data signal transmitted over the radio interface must be protected from errors. GSM uses convolution encoding and block interleaving to achieve this protection. The exact algorithms used differ for speech and for different data rates. The method used for speech blocks will be described below.Recall that the speech codec produces a 260 bit block for every 20 ms speech sample. From subjective testing, it was found that some bits of this block were more important for perceived speech quality than others. The bits are thus divided into three classes: Class Ia 50 bits - most sensitive to bit errors Class Ib 132 bits - moderately sensitive to bit errors Class II 78 bits - least sensitive to bit errorsClass Ia bits have a 3 bit Cyclic Redundancy Code added for error detection. If an error is detected, the frame is judged too damaged to be comprehensible and it is discarded. It is replaced by a slightly attenuated version of the previous correctly received frame. These 53 bits, together with the 132 Class Ib bits and a 4 bit tail sequence (a total of 189 bits), are input into a 1/2 rate convolutional encoder of constraint length 4. Each input bit is encoded as two output bits, based on a combination of the previous 4 input bits. The convolutional encoder thus outputs 378 bits, to which are added the 78 remaining Class II bits, which are unprotected. Thus every 20 ms speech sample is encoded as 456 bits, giving a bit rate of 22.8 kbps.To further protect against the burst errors common to the radio interface, each sample is interleaved. The 456 bits output by the convolutional encoder are divided into 8 blocks of 57 bits, and these blocks are transmitted in eight consecutive time-slot bursts. Since each time-slot burst can carry two 57 bit blocks, each burst carries traffic from two different speech samples.Recall that each time-slot burst is transmitted at a gross bit rate of 270.833 kbps. This digital signal is modulated onto the analog carrier frequency using

Traffic channelsA traffic channel (TCH) is used to carry speech and data traffic. Traffic channels are defined using a 26-frame mult iframe, or group of 26 TDMA frames. The length of a 26-frame multiframe is 120 ms, which is how the length of a burst period is defined (120 ms divided by 26 frames divided by 8 burst periods per frame). Out of the 26 frames, 24 are used for traffic, 1 is used for the Slow Associated Control Channel (SACCH) and 1 is currently unused (see Figure 2). TCHs for the uplink and downlink are separated in time by 3 burst periods, so that the mobile station does not have to transmit and receive simultaneously, thus simplifying the electronics.In addition to these full-rate TCHs, there are also half-rate TCHs defined, although they are not yet implemented. Half-rate TCHs will effectively double the capacity of a system once half-rate speech coders are specified (i.e., speech coding at around 7 kbps, instead of 13 kbps). Eighth-rate TCHs are also specified, and are used for signaling. In the recommendations, they are called Stand-alone Dedicated Control Channels (SDCCH).

Figure 2. Organization of bursts, TDMA frames, and multiframes for speech and dataControl channelsCommon channels can be accessed both by idle mode and dedicated mode mobiles. The common channels are used by idle mode mobiles to exchange the signaling information required to change to dedicated mode. Mobiles already in dedicated mode monitor the surrounding base stations for handover and other information. The common channels are defined within a 51-frame multiframe, so

factor to consider is that when the transmitter is turned off, there is total silence heard at the receiving end, due to the digital nature of GSM. To assure the receiver that the connection is not dead, comfort noise is created at the receiving end by trying to match the characteristics of the transmitting end's background noise.Discontinuous receptionAnother method used to conserve power at the mobile station is discontinuous reception. The paging channel, used by the base station to signal an incoming call, is structured into sub-channels. Each mobile station needs to listen only to its own sub-channel. In the time between successive paging sub-channels, the mobile can go into sleep mode, when almost no power is used.Power controlThere are five classes of mobile stations defined, according to their peak transmitter power, rated at 20, 8, 5, 2, and 0.8 watts. To minimize co-channel interference and to conserve power, both the mobiles and the Base Transceiver Stations operate at the lowest power level that will maintain an acceptable signal quality. Power levels can be stepped up or down in steps of 2 dB from the peak power for the class down to a minimum of 13 dBm (20 mill watts).The mobile station measures the signal strength or signal quality (based on the Bit Error Ratio), and passes the information to the Base Station Controller, which ultimately decides if and when the power level should be changed. Power control should be handled carefully, since there is the possibility of instability. This arises from having mobiles in co-channel cells alternating increase their power in response to increased co-channel interference caused by the other mobile increasing its power. This in unlikely to occur in practice but it is (or was as of 1991) under study.Network aspectsEnsuring the transmission of voice or data of a given quality over the radio link is only part of the function of a cellular mobile network. A GSM mobile can seamlessly roam nationally and internationally, which requires that registration, authentication, call routing and location updating functions exist and are standardized in GSM networks. In addition, the fact that the geographical area covered by the network is divided into cells necessitates the implementation of a handover mechanism. These functions are performed by the Network Subsystem, mainly using the Mobile Application Part (MAP) built on top of the Signaling System No. 7 protocol.

Gaussian-filtered Minimum Shift Keying (GMSK). GMSK was selected over other modulation schemes as a compromise between spectral efficiency, complexity of the transmitter, and limited spurious emissions. The complexity of the transmitter is related to power consumption, which should be minimized for the mobile station. The spurious radio emissions, outside of the allotted bandwidth, must be strictly controlled so as to limit adjacent channel interference, and allow for the co-existence of GSM and the older analog systems (at least for the time being).Multipath equalizationAt the 900 MHz range, radio waves bounce off everything - buildings, hills, cars, airplanes, etc. Thus many reflected signals, each with a different phase, can reach an antenna. Equalization is used to extract the desired signal from the unwanted reflections. It works by finding out how a known transmitted signal is modified by multipath fading, and constructing an inverse filter to extract the rest of the desired signal. This known signal is the 26-bit training sequence transmitted in the middle of every time-slot burst. The actual implementation of the equalizer is not specified in the GSM specifications.Frequency hoppingThe mobile station already has to be frequency agile, meaning it can move between a transmit, receive, and monitor time slot within one TDMA frame, which normally are on different frequencies. GSM makes use of this inherent frequency agility to implement slow frequency hopping, where the mobile and BTS transmit each TDMA frame on a different carrier frequency. The frequency hopping algorithm is broadcast on the Broadcast Control Channel. Since multipath fading is dependent on carrier frequency, slow frequency hopping helps alleviate the problem. In addition, co-channel interference is in effect randomized.Discontinuous transmissionMinimizing co-channel interference is a goal in any cellular system, since it allows better service for a given cell size, or the use of smaller cells, thus increasing the overall capacity of the system. Discontinuous transmission (DTX) is a method that takes advantage of the fact that a person speaks less that 40 percent of the time in normal conversation [22], by turning thetransmitter off during silence periods. An added benefit of DTX is that power is conserved at the mobile unit.The most important component of DTX is, of course, Voice Activity Detection. It must distinguish between voice and noise inputs, a task that is not as trivial as it appears, considering background noise. If a voicesignal is misinterpreted as noise, the transmitter is turned off and a very annoying effect called clipping is heard at the receiving end. If, on the other hand, noise is misinterpreted as a voicesignal too often, the efficiency of DTX is dramatically decreased. Another

Figure 3. Signaling protocol structure in GSMThe signaling protocol in GSM is structured into three general layers [1], [19], depending on the interface, as shown in Figure 3. Layer 1 is the physical layer, which uses the channel structures discussed above over the air interface. Layer 2 is the data link layer. Across the Um interface, the data link layer is a modified version of the LAPD protocol used in ISDN, called LAPDm. Across the A interface, the Message Transfer Part layer 2 of Signaling System Number 7 is used. Layer 3 of the GSM signaling protocol is itself divided into 3 sub layers.Radio Resources ManagementControls the setup, maintenance, and termination of radio and fixed channels, including handovers.Mobility ManagementManages the location updating and registration procedures, as well as security and authentication.Connection ManagementHandles general call control, similar to CCITT Recommendation Q.931, and manages Supplementary Services and the Short Message Service.Signaling between the different entities in the fixed part of the network, such as between the HLR and VLR, is accomplished through the Mobile Application Part (MAP). MAP is built on top of the Transaction Capabilities Application Part (TCAP, the top layer of Signaling System Number 7. The specification of the MAP is quite complex, and at over 500 pages, it is one of the longest documents in the GSM recommendations [16].Radio resources managementThe radio resources management (RR) layer oversees the establishment of a link, both radio and fixed, between the mobile station and the MSC. The main functional components involved are the mobile station, and the Base Station Subsystem, as well as the MSC. The RR layer is concerned with the management of an RR-session [16], which is the time that a mobile is in__________________

location update message is sent to the new MSC/VLR, which records the location area information, and then sends the location information to the subscriber's HLR. The information sent to the HLR is normally the SS7 address of the new VLR, although it may be a routing number. The reason a routing number is not normally assigned, even though it would reduce signaling, is that there is only a limited number of routing numbers available in the new MSC/VLR and they are allocated on demand for incoming calls. If the subscriber is entitled to service, the HLR sends a subset of the subscriber information, needed for call control, to the new MSC/VLR, and sends a message to the old MSC/VLR to cancel the old registration.For reliability reasons, GSM also has a periodic location updating procedure. If an HLR or MSC/VLR fails, to have each mobile register simultaneously to bring the database up to date would cause overloading. Therefore, the database is updated as location updating events occur. The enabling of periodic updating, and the time period between periodic updates, is controlled by the operator, and is a trade-off between signaling traffic and speed of recovery. If a mobile does not register after the updating time period, it is deregistered.A procedure related to location updating is the IMSI attach and detach. A detach lets the network know that the mobile station is unreachable, and avoids having to needlessly allocate channels and send paging messages. An attach is similar to a location update, and informs the system that the mobile is reachable again. The activation of IMSI attach/detach is up to the operator on an individual cell basis.Authentication and securitySince the radio medium can be accessed by anyone, authentication of users to prove that they are who they claim to be, is a very important element of a mobile network. Authentication involves two functional entities, the SIM card in the mobile, and the Authentication Center (AuC). Each subscriber is given a secret key, one copy of which is stored in the SIM card and the other in the AuC. During authentication, the AuC generates a random number that it sends to the mobile. Both the mobile and the AuC then use the random number, in conjunction with the subscriber's secret key and a ciphering algorithm called A3, to generate a signed response (SRES) that is sent back to the AuC. If the number sent by the mobile is the same as the one calculated by the AuC, the subscriber is authenticated [16].The same initial random number and subscriber key are also used to compute the ciphering key using an algorithm called A8. This ciphering key, together with the TDMA frame number, use the A5 algorithm to create a 114 bit sequence that is XO Red with the 114 bits of a burst (the two 57 bit blocks). Enciphering is an option for the fairly paranoid, since the signal is already coded, interleaved, and

dedicated mode, as well as the configuration of radio channels including the allocation of dedicated channels.An RR-session is always initiated by a mobile station through the access procedure, either for an outgoing call, or in response to a paging message. The details of the access and paging procedures, such as when a dedicated channel is actually assigned to the mobile, and the paging sub-channel structure, are handled in the RR layer. In addition, it handles the management of radio features such as power control, discontinuous transmission and reception, and timing advance.HandoverIn a cellular network, the radio and fixed links required are not permanently allocated for the duration of a call. Handover, or handoff as it is called in North America, is the switching of an on-going call to a different channel or cell. The execution and measurements required for handover form one of basic functions of the RR layer.There are four different types of handover in the GSM system, which involve transferring a call between: Channels (time slots) in the same cell Cells (Base Transceiver Stations) under the control of the same Base Station Controller (BSC), Cells under the control of different BSCs, but belonging to the same Mobile services Switching Center (MSC), and Cells under the control of different MSCs.The first two types of handover, called internal handovers, involve only one Base Station Controller (BSC). To save signaling bandwidth, they are managed by the BSC without involving the Mobile services Switching Center (MSC), except to notify it at the completion of the handover. The last two types of handover, called external handovers, are handled by the MSCs involved. An important aspect of GSM is that the original MSC, the anchor MSC, remains responsible for most call-related functions, with the exception of subsequent inter-BSC handovers under the control of the new MSC, called the relay MSC.Handovers can be initiated by either the mobile or the MSC (as a means of traffic load balancing). During its idle time slots, the mobile scans the Broadcast Control Channel of up to 16 neighboring cells, and forms a list of the six best candidates for possible handover, based on the received signal strength. This information is passed to the BSC and MSC, at least once per second, and is used by the handover algorithm.

The algorithm for when a handover decision should be taken is not specified in the GSM recommendations. There are two basic algorithms used, both closely tied in with power control. This is because the BSC usually does not know whether the poor signal quality is due to multipath fading or to the mobile having moved to another cell. This is especially true in small urban cells.The 'minimum acceptable performance' algorithm [3] gives precedence to power control over handover, so that when the signal degrades beyond a certain point, the power level of the mobile is increased. If further power increases do not improve the signal, then a handover is considered. This is the simpler and more common method, but it creates 'smeared' cell boundaries when a mobile transmitting at peak power goes some distance beyond its original cell boundaries into another cell.The 'power budget' method [3] uses handover to try to maintain or improve a certain level of signal quality at the same or lower power level. It thus gives precedence to handover over power control. It avoids the 'smeared' cell boundary problem and reduces co-channel interference, but it is quite complicated.Mobility managementThe Mobility Management layer (MM) is built on top of the RR layer, and handles the functions that arise from the mobility of the subscriber, as well as the authentication and security aspects. Location management is concerned with the procedures that enable the system to know the current location of a powered-on mobile station so that incoming call routing can be completed.Location updatingA powered-on mobile is informed of an incoming call by a paging message sent over the PAGCH channel of a cell. One extreme would be to page every cell in the network for each call, which is obviously a waste of radio bandwidth. The other extreme would be for the mobile to notify the system, via location updating messages, of its current location at the individual cell level. This would require paging messages to be sent to exactly one cell, but would be very wasteful due to the large number of location updating messages. A compromise solution used in GSM is to group cells into location areas. Updating messages are required when moving between location areas, and mobile stations are paged in the cells of their current location area.The location updating procedures, and subsequent call routing, use the MSC and two location registers: the Home Location Register (HLR) and the Visitor Location Register (VLR). When a mobile station is switched on in a new location area, or it moves to a new location area or different operator's PLMN, it must register with the network to indicate its current location. In the normal case, a

transmitted in a TDMA manner, thus providing protection from all but the most persistent and dedicated eavesdroppers.Another level of security is performed on the mobile equipment itself, as opposed to the mobile subscriber. As mentioned earlier, each GSM terminal is identified by a unique International Mobile Equipment Identity (IMEI) number. A list of IMEIs in the network is stored in the Equipment Identity Register (EIR). The status returned in response to an IMEI query to the EIR is one of the following:White-listedThe terminal is allowed to connect to the network.Grey-listedThe terminal is under observation from the network for possible problems.Black-listedThe terminal has either been reported stolen, or is not type approved (the correct type of terminal for a GSM network). The terminal is not allowed to connect to the network.Communication managementThe Communication Management layer (CM) is responsible for Call Control (CC), supplementary service management, and short message service management. Each of these may be considered as a separate sub layer within the CM layer. Call control attempts to follow the ISDN procedures specified in Q.931, although routing to a roaming mobile subscriber is obviously unique to GSM. Other functions of the CC sub layer include call establishment, selection of the type of service (including alternating between services during a call), and call release.Call routingUnlike routing in the fixed network, where a terminal is semi-permanently wired to a central office, a GSM user can roam nationally and even internationally. The directory number dialed to reach a mobile subscriber is called the Mobile Subscriber ISDN (MSISDN), which is defined by the E.164 numbering plan. This number includes a country code and a National Destination Code which identifies the subscriber's operator. The first few digits of the remaining subscriber number may identify the subscriber's HLR within the home PLMN.An incoming mobile terminating call is directed to the Gateway MSC (GMSC) function. The GMSC is basically a switch which is able to interrogate the subscriber's HLR to obtain routing information, and thus contains a table linking MSISDNs to their corresponding HLR. A simplification is to have a GSMC handle one specific PLMN. It should be noted that the GMSC function is distinct from the MSC function, but is usually implemented in an MSC.

The routing information that is returned to the GMSC is the Mobile Station Roaming Number (MSRN), which is also defined by the E.164 numbering plan. MSRNs are related to the geographical numbering plan, and not assigned to subscribers, nor are they visible to subscribers.The most general routing procedure begins with the GMSC querying the called subscriber's HLR for an MSRN. The HLR typically stores only the SS7 address of the subscriber's current VLR, and does not have the MSRN (see the location updating section). The HLR must therefore query the subscriber's current VLR, which will temporarily allocate an MSRN from its pool for the call. This MSRN is returned to the HLR and back to the GMSC, which can then route the call to the new MSC. At the new MSC, the IMSI corresponding to the MSRN is looked up, and the mobile is paged in its current location area (see Figure 4).

Figure 4. Call routing for a mobile terminating callConclusion and commentsIn this paper I have tried to give an overview of the GSM system. As with any overview, and especially one covering a standard 6000 pages long, there are many details missing. I believe, however, that I gave the general flavor of GSM and the philosophy behind its design. It was a monumental task that the original GSM committee undertook, and one that has proven a success, showing that international cooperation on such projects between academia, industry, and government can succeed. It is a standard that ensures interoperability without stifling competition and innovation among suppliers, to the benefit of the public both in terms of cost and service quality. For example, by using Very Large Scale Integration (VLSI) microprocessor technology, many functions of the mobile station can be built on one chip set, resulting in lighter, more compact, and more energy-efficient terminals.

Telecommunications are evolving towards personal communication networks, whose objective can be stated as the availability of all communication services anytime, anywhere, to anyone, by a single identity number and a pocket able communication terminal [25]. Having a multitude of incompatible systems throughout the world moves us farther away from this ideal. The economies of scale created by a unified system are enough to justify its implementation, not to mention the convenience to people of carrying just one communication terminal anywhere they go, regardless of national boundaries.The GSM system, and its sibling systems operating at 1.8 GHz (called DCS1800) and 1.9 GHz (called GSM1900 or PCS1900, and operating in North America), are a first approach at a true personal communication system. The SIM card is a novel approach that implements personal mobility in addition to terminal mobility. Together with international roaming, and support for a variety of services such as telephony, data transfer, fax, Short Message Service, and supplementary services, GSM comes close to fulfilling the requirements for a personal communication system: close enough that it is being used as a basis for the next generation of mobile communication technology in Europe, the Universal Mobile Telecommunication System (UMTS).Another point where GSM has shown its commitment to openness, standards and interoperability is the compatibility with the Integrated Services Digital Network (ISDN) that is evolving in most industrialized countries, and Europe in particular (the so-called Euro-ISDN). GSM is also the first system to make extensive use of the Intelligent Networking concept, in which services like 800 numbers are concentrated and handled from a few centralized service centers, instead of being distributed over every switch in the country. This is the concept behind the use of the various registers such as the HLR. In addition, the signaling between these functional entities uses Signaling System Number 7, an international standard already deployed in many countries and specified as the backbone signaling network for ISDN.GSM is a very complex standard, but that is probably the price that must be paid to achieve the level of integrated service and quality offered while subject to the rather severe restrictions imposed by the radio environment.

Testing Mic and speakerFor Mic

Set your multimeter on continuity rang 1X ,put red prod on center of mic (+mic ) and black prod on body ornegative , its will show some reading , its healthy now , after thatcheck its shortage, change your prods and vice versa it , now it willshow high resistance, mean needle will not move, now confirm you mic ishealthy .

For Speaker

By using analog multimeter ,select rang 1X for continuity, put any prod at any terminal of speaker,put one prod constantly at any terminal , and touch other prod toremaining terminal of speaker try to listen click form speaker, aclicking sound can be hear. its mean you speaker is working , and meterwill show speaker ohm tooCharging Faults

charging faults are mainly of three types No charging Not charging Auto chargingNo charging:in this fault a mobile phone does not charge at all when charging pin is inserted nothing happens it is always due to damaged fuse. or broken charging supply track if we repair fuse or jumper broken tracks we can set this fault off.but on the first step I am telling you how to check no charging fault. Check Your battery if it is not connected properly no charging fault occurs. check continuity between charging pins it should be nor full nor high resistance. if it is showing full continuity then there may be some problem in your charging IC may it is totally short you can re hot /replace this IC. if there is no continuity in charging pins 90% fuse is damaged. you can replace fuse or jumper it. if a fuse shows full continuity in multi meter then it is working correctly if it is not so it is damaged. if fuse is not damaged you can check tracks if broken. if fuse, battery and tracks are ok then charging IC would be damaged.

Not charging:in this fault a mobile phone shows a message "Not charging" on the screen when ever it is connected with charging pins. this type of fault is not a mere hardware fault it is 90% software fault. this fault is present only in nokia and I personally experienced a problem with a nokia 3100 it was showing "Notcharging " i tried hardware solutions but totally in vain so I upgraded my software now every thing was ok. . and this is the same case in many types of nokia brands you can check this up.Only nokia 1100 when "Not charging" fault comes it is very hard to remove this fault in nokia 1100 I only repaired a little number of nokia 1100 displaying this message there was a problem in charge connector diode next tocharging fuse. but often it can be solved by repairing software or upgrading it.Auto Charging:In auto charging a phone continues showing charging despite of removing charging pin from phone. in this type of fault the "BSI" pin of mobile phone is very important because it is used to tell the phone what is the state of mobile phone charging now so if this pin is not ok this fault occurs. there are some cases in which a mobile phone battery is ok but auto charging is present you can check transistors if used in charging section and if faulty replace it because this transistor is used in some mobile phones to cut off charging from phone automatically. in In some cases a resistance in charging section is responsible for that which is marked as "R22" in charging section so you can check "+" supply connection with this

Nokia Basics for BeginnersA normal battery has only two terminals brought out of its casing. But the batteries used in Mobile Phones, many times have more than 2, at least 3 or even 4 (at the most) terminals brought out on its casing. You may wonder why so? It is very interesting to go into the details and know more about it. Though the charging circuit inside a mobile phone is generally designed with providing a very very safe charging voltage to the battery, it is made more perfect with the use of this additional terminals provided on the battery casing.

Let us see why it is thought necessary, to provide more than the normal 2 terminals in Mobile Phones Batteries. Take the case of a Nokia phone 3310 or 3315. You may notice that for this particular model of the phone the batteries available are of both the types, Ni-Mh as well as Li Ion types. It is necessary to inform you at this stage that not only the charging current may differ in these two different kinds of batteries but also the voltage level up to which they can be charged safely will also differ in them. To be more specific, the Ni-Mh battery can be charged safely up to 5.2 volts whereas the Li Ion batterys safe voltage is only 4.8 volts. So the same circuit in the mobile phone will have to stop charging the batteries at different levels of voltages in each case. So how it will know which kind of battery is inserted in the mobile phone and to be charged and so at which level to stop charging in each of the case? This is achieved with the help of a standard, pre-decided or pre-determined by all the battery manufacturers according to which they put extra components inside each battery casing which will bring a certain predetermined voltage level at that point called BSI (Battery Size Indicator), which will help not only to know the type of battery it is but will also let us know its capacity in mAH!!!! Isnt it very intelligent?Yes, it is a very nice way of letting the charging circuit to know how much charging current it should supply and on reaching which level of voltage, it should stop supplying the charging current to the battery. I am sure, all of you would like to now how this is achieved. The following details taken from the technical pages for the Nokia Model 3310 will help you understand this better.The type of the battery inserted in the mobile phone is found out by the think-tank of the phone, which is the CPU (Central processing Unit) of the mobile phone. In the case of Nokia 3310-3315 models it is the IC known as MAD IC, which is actually the CPU of the mobile phone. This is done by the CPU with the help of the Charging Control IC of the phone CCONT IC. The CCONT IC reads the voltage at a point on the battery called the BSI line. The Batteries contain a pull-down (connected to either ground or the ve terminal of the battery) resistor inside the battery casing. Typically, for a BLB-2 type of Nokia battery (Li Ion 650 mAH), it is a 68Kohms resistor. Other values used in other types of batteries are listed in the table below:Battery Type and its capacity Value of the pull down resistor inside the batteryBMC-2 Ni-Mh 640mAH 3.3K (3.3K=3.3Kohms=3300ohms)BMC-3 Ni-Mh 900mAH 5.6KBLB- 2 Li-Ion 650 mAH 68KBLC- 2 Li-Ion 900 mAH 75K

How would this help identifying the type of battery?Let us try to visualize the schematic of the Battery related components. This BSI point of the Battery is connected as shown below in the figure via a 10K resistor to a point on the CCONT IC. Also it is connected to 2.8volts supply line via a pull-up resistor of a value fixed at 150K.

To view the pictures here, please download the attached file.

The thermistor RT is a thermal kind of resistor, whose value decreases as its temperature rises. As above in the case of BSI point, the BTEMP point of theBattery is connected with a pull-up (to pull up the voltage) resistor of 100K to a Vref positive voltage point. This 100K resistor on the BTEMP point is also connected to ground point via our thermal resistor Rt. So the voltage at BTEMP point is dependent on the value of Rt, right?

When the Battery is put for charging in the mobile phone, there is normally a little rise in the temperature of the battery. This will cause a rise in temperature of the Resistance RT inside the battery casing. Now as per the characteristic of the NTC resistor , its resistance value decreases as its temperature rises. This also changes thevoltage at the BTEMP point of the battery as well as the CCONT BTEMP pin. This change is always fed to the CPU which keeps monitoring it continuously. This is always online referred to the Energy Managemant Software loaded in the Memory ICs (Flash & RAM ICs) insidethe phone. When the temperature inside the battery increases beyond its allowed limit, this change in voltage at the BTEMP point will be processed in the CPU and the Memory ICs and the CPU will then ask the CCONT IC to stop supplying thecharging current to the battery and will stop charging absolutely to save the battery from any damage that may occur due to its rise in temperature.

Thus, in Nokia 3310-3315-3330-3390 etc. series of Phones, all the functions of charging are achieved very accurately and perfectly with the use of :(1) Chaps (Charging IC) -N200 #U423V2G36T(2) CCONT (Charging Controller IC) -N201(3) MAD (CPU IC) -D300#MAD2WD1_ROM6-V16-uBGA(4) Memory ICs (Flash & RAM ICs) -D301 #M28W160T100GB6T (FLASH IC 1Mx16) ; D302 #K6F1016U4A-FF10T00 (SRAM 64Kx16) &(5) Energy Management Software loaded in the Flash IC.

A dead (not powering on) DCT3 phoneIf you have a dead Nokia DCT3 phone on your hand like a 3310, you should ideally try flashing it first before looking for a fault in the hardware section ofthe phone . Many such phones have gone dead because of a corrupted software and can be easily put to life (revived) by just flashing it properly.By and large tools like UFS,Twister,JAF etc. are good for Nokia phones in general, but when it comes to flashing a DCT3 phone, I personally prefer to use the Dejan Cable set with Rolis Flasher and Noktool to revive the software damaged DCT3 phones. However, if you have any of this tools (UFS,Twister,JAF etc.)and on attachingthe phone to it, if you get the message "1st boot error"', then the problem is in hardware section of the phone and it will not help to flash the phone at all. However, even if you flashed it with proper latest version flash files, REST ASSURED that no damage will be done and you will have aan upgraded phone when you finally are able to revive it !!!!!!!!Attached here is a very nice tutorial for flashing DCT3 phones using Rolis Flasher and Noktool.

3310_Blocks_1 :

[b]The Basic Phone Model selected for our study is NOKIA 3310. This 3310 phone has many modified additions to its family like 3315,3330,3350,3390 to mention the popular ones.

To understand the working pattern of this Mobile Phone, this 3310 phone can be split into 4 sections :(1) Signal Processing Section, which consists of RF Section, IF Section and lastly the Audio Section. We can see in the block that this Signal Processing Section is working in 2 directions. The Signal carrying the voice signals of the person on the other side is entering the Antenna and is called the Rx signal and it gets processed in the RF,IF and finally the AF or the Audio Sections ofthe phone to be available for hearing thro the SPEAKER. Similarly, the Voice Signal picked up by the MICrophone of the phone is the Signal to be Transmitted and so becomes the Tx signal passing in the opposite direction of the Rx Signal to reach the Tower thro the Antenna of ourMobile Phone .(2) Logic Section which consists of the CPU and the FLASH and RAM sections. Logic Section works according to the program stored in the flash IC. The CPU or theCentral Processing Unit of the phone makes this section the Brain of the whole unit. All the logic or the intelligence is stored in the memory devices the FLASH and the RAM chips in this section. Like a Guardian in the Family, the CPU keeps a Constant watch on most of the activities taking place inthe phone and sends the correcting commands or signals to appropriate Sections as and when necessary. It takes help of its allies, the FLASH & RAM chips to take a decision by making references stored in them for comparision. Some of the activitiesit is monitoring are : (i) Strength of the received signal (ii) battery voltage (iii) charging current (iv) battery temperature (v) charging voltage (vi) clock or timing related functions (vii) memory availability (viii) on or off state of the phone (ix) sim data for synchronizing with the service provider data (x) availability of services subscribed with the service provider like Calling number identification (Caller ID availability), Call waiting, Call Diverting, Call Forwarding etc. (xi) most importantly the validity of the IMEI check both for its internal verification as well as for validating by the service provider for blacklisted IMEI numbers.(3) UI (User Interface ) Section consisting of Speaker, Microphone, LCD Display, LCD LEDs, KEYPAD LEDs, Vibrator, Buzzer and KEYPAD Assemblies. I believe this are self explanatory parts or functions and hardly need any description.

(4) Power Supply Section which consists of the Charging Circuit, the Battery, the Power Distribution Section and the SIM CIRCUIT. With the help of the CPU and its allied logical allies, a perfectly tuned battery charging function is achieved for best performance and long life of the battery. Also power is distributed from the Battery to all the sections of the phone from this section with the help of the Power Distributor Chip.Also this section reads the data stored in the SIM Card and refers it to the CPU or the logic section to further process and validate it with the help of Signal Processing Section so that the mobile phone gets the access and remain connected to the network of the SIM Card provider company also called the service provider company.

3310_Blocks_2 :

The Major Parts used in the above Sections are as follows :

(1)Signal Processing SectionZ502 Antenna Switch (DIPLEXER)Z501 Dual Frequency Band Pass FilterV501 HF (High Frequency) Amplifier for 900MHz SignalV500 HF (High Frequency) Amplifier for 1800MHz SignalZ500 Dual Freq. band Pass FilterN500 HAGAR IC Demodulates Rx Signal and Modulates the Tx SignalG500 Local Oscillator (VCO-Voltage Controlled Oscillator)G502 26MHz OscillatorN503 Regulating IC (Converts 5V to 3.8V with Control Signal of 2.8Vreceived as HAGAR Reset Control Signal from CPUN100 COBBA IC Converts the incoming Rx Digital Signal to Rx AnalogSignal and similarly converts the outgoing Tx Analog signal to TxDigital SignalZ503 GSM (900MHz) Tx FilterN502 PA (Power Amplifier) for outgoing Tx Signal

(2)Logic SectionD300 CPU called MAD ICD301 FLASH ICD302 RAM IC(3)UI (User Interface ) SectionN400 UI (User Interface) IC

(4)Power Supply SectionN200 Charging IC called CHAPSN201 Power Controller IC called CCONTX400 SIM Card Socket

RF SECTION OF NOKIA 3310 Mobile Phone:Mobile Phones make use of Filters called Dual Band-pass filters because they need to allow two frequencies of signals most commonly 900MHz and 1800MHz in the dual band mobile phones. Also Antenna Switches are used in Mobile Phones expensively at the very first stage of the point of entry of the signal (called the received signal Rx) into the mobile phone which also eventually becomes the point of exit for the outgoing signal or the transmitted signal Tx. The newer models of the Mobile Phones like a Nokia 6600 makes use of an active Antenna Switch which also has a built-in amplifier circuit inside it to immediately boost the Rx signal.

See this COMPONENTS closely in the PICTURE OF NOKIA 3310 Mobile phone PCB in the jpg file attached below

Locate the DIAGONAL cut on one of the corner of the IC and start counting the vertical pins from this cut as 1,2,3...and the horizontal pins as A,B,C ...This way you prepare an imaginary matrix ofRows (1,2,3 ...) and Columns (A,B,C...).

So the pin in the Column A and Row 1 is A1the pin in the Column A and Row 2 is A2.................................................. ..the pin in the Column F and Row 8 is F8

The diagram in the attached file is useful to understand this concept.

Here are some diagrams which will be helpful to all Beginners to start tracing the RF Section of the Nokia 3310 phone.

Please use Multimeter to trace the Circuit.

Set the Multimeter to lowest range of resistance setting available on the Multimeter or to "Beep" mode in the Digital Multimeter to check continuity between two points of the PCB.

Put one probe (any one of the red or black wires) on the point marked "Start Here" in the first picture below, which is the "Built-in Antenna Pad" and put the other probe on the other end/s of the Blue Line starting from this starting point in the first picture below.

You will find 3 points connected to the other end of this blue line -a capacitor C593,a coil L510 and pin no.4 on the Antenna Switch Z502.

You should get a continuity indication between the Antenna Pad point and one end of this 3 parts. If you are using a analog multimeter, you should get a full deflection moving the pointer to the "0" mark on the Resistance scale of your Analog Multimeter. If you are using a digital multimeter in the lowest resistance range, you should get a 00.0 (all zeroes) reading and if you are using the digital multimeter in the "Beep" mode, you should hear a clear beep indicating a continuity in the circuit.

If you are not getting the continuity, it means that there is a break in the track connecting these points on the PCB and you should repair it by putting a jumper between the points thus disconnected.

You should try and co-relate this tracing with the help of the circuit diagram of the same section, the picture of which is also included here

Continuing our tracing lession of the RF section of the Famous Nokia 3310/3315 phone, i post here some more pictures. Please note that now in the beginning you don't need to look at the WHOLE PCB with so many parts scattered all over it or even the large complete schematic of our phone. Let us not think about every thing in the beginning.

Please try to concentrate only on a very small section of our circuit and the part of the actual circuit as posted before, just made up of Antenn Pad + 3 parts viz.Capacitor C593, Coil L510 and the Antenna Switch Z502 marked in the new picture viz.19_1_0.jpg with a flouroscent green ellipse (circle) or a flouroscent green round edged square in the attached picture. You also need to ignore for the moment all other writings on this small picture and concentrate only on these parts identified by their names in the red rectangles with a yellow background.

Now that you would have correctly located the parts you are going to trace in the circuit diagram, you will be more comfortable, i believe.

STEP 1: As you must have observed in the schematic posted before, that the Ant.PAD is getting connected to one point of the Capacitor C593, you must check this by placing Black Probe on the Ant.PAD and the Red Probe on one end marked as "Red Probe (1)" in the next picture posted today viz.19_1_1.jpg. When you connect the multimeter as illustrated in this picture, it should show continuity (Full deflection of the needle to "0" position in the analog meter and a beep or a 000 reading on the digitalmultimeter.).

STEP 2 :Similarly keeping the Black Probe in the same position on the Ant.PAD and moving the Red Probe from it's position at "Red Probe (1)" to one end of the Coil L510 marked as "Red Probe (2)" will also show continuity in the meter by needle moving to"0" position on the scale of the analog meter and a beep or 000 reading on the digitalmultimeter.

STEP 3: It can also be observed using a magnifying lamp that these ends of C593 and L510 are connected with each other on the PCB with the help of the Copper Track. This can also be verified by connecting the meter as shown in the next picture i.e. 19_1_2.jpg.

STEP 4 :Also you will be able to see in this picture that the other end of the Coil L510 is getting connected to the think ground track on the PCB. You may as well check this also with the multimeter.

STEP 5 :Now the only connection left to be verified/traced is that between the other end of C593 and Pin 2 of the Antenna Switch Z502.This you can easily check by connecting the black probe to this other end of C593 and the Red Probe to Pin no.2 of Z502. For continuity the meter will show as before. This, i have illustrated in the picture 19_1_3.jpg attached here.Attached Thumbnails

3310 RX sectionof Nokia 3310-3315.Here the Capacitor C593 serves the purpose of carrying the required signal picked up by the Antenna to the Ant.Sw.Z502. As you may know, it's value (Capacitance) 22pf is selected to help carry our band or bands (900 MHz and 1800 MHz) of signals more efficiently than the other signals. In spite of having selected the best suitable value of C593, there may still be many unwanted signals of other frequencies and this will be removed by the coil L510 by sending them to the ground path.Natural, the value or the Inductance of this Coil (27uH) is also selected with a view to trapping this unwanted signals.

The Antenna Switch Z502 is also called a Diplexer. In Rx mode, it receives the signal at it's Pin no.4 from the capacitor C593 and then processes them to separate them out into two separate signals of 900MHz and 1800 MHz at it's pin nos. 14 and 12 respectively.

Now further ahead, this two separated signals of 900 MHz and 1800 MHz are given via Capacitors C556(27pf) for 900 MHz and C547(15pf) for 1800 MHz, respectively to pin nos.7 and 5 of the Dual Frequency Band Pass Filter Z501. It's function again is to smoothen out both the signals to more purer or clean signals by removing the traces of any unwanted signals from them which may have still been remaining with them.

So, in short till now, the Ant.Sw. has separated the two signals of 900 & 1800 MHz and the DFBP filter has filtered or cleaned them to provide a clear signal.

3310-3315 RF Section Description :

Rx Receiving Section of Nokia 3310-3315 Phones:

(1) Beginning from Antenna Switch Z502 : Antenna receives the incoming signal Rx. This signal contains the required signals as well as signals which are not required or not desired to be present or just UNWANTED signals in simple words. This unwanted signals are simply trapped and sent to ground by the coil L510. In this way the unwanted signals are blocked here by the coil L510 and so are prevented from proceeding further. The Capacitor C593 picks up the desired signal and passes them on further to theAntenna Switch Z502 (at Pin No.4).So, the desired RF signal is passed on to the Antenna Switch , which processes it and separates the 2 different frequency signals received thus and provides them separately at its output pins 14 & 12. The 900 MHz signal is made available at its pin no.14 and 1800MHz signal is made available at its pin no.12 as shown in the diagram below.

3310-3315 RF Section Description Part II:

(2) Next Component in the RF Section is the Dual Frequency Band Pass Filter (DFBPF) Z501. It receives the two signals of 900 MHz and 1800 MHz respectively from pins 14 and 12 of Z502 through capacitors C556 and C547 respectively as you can see in the figure above. What this DFBPF does is again similar to what coil L510 and Capacitor C593 did before, that is to say, allow required frequency signals to pass further to the next stage and block or not allow the other unwanted signals to pass to the next stage. This is the exact meaning of the word Filter. The Components C545, L507, C541 connected to pin no.1 of DFBPF Z501 (where 900 MHZ signal is obtained) and C510, L505 & C525 connceted to pin no.3 of DFBPF Z501 (where 1800 MHZ signal is obtained) are also meant basically for the same kind of functioning of passing the wanted signals and blocking the unwanted signals to the next stage for further processing.

3310-3315 RF Section Description Part III3310-3315 RF Section Description Part III:(3) V501 & V500 respectively are the next components where the signals of 900 MHz & 1800 MHz reach after passing through the 2nd DFBPF (dual Freq.bandpass Filter) Z501. Their respective input points pins are no.2 (V501) & no.1 (V500). These devices V501 & V500 are HF (High Frequency) amplifier's. They amplify or boost or increase the strengths of the signals received at its inputs. The amount of amplification obtained or given here is controlled by the AGC (Automatic gain Control) voltage applied at their BIAS pins and is received from the IF IC (HAGAR IC) N500. This N500 HAGAR IC has measured the strength of the received signal and compared it with a reference signal to know if it is sufficient or less or more thank the reference signal. If the strength of the received signal is found to be less than required, the HAGAR IC changes the control voltage fed to this HF Amplifier in such a way that the amplification is increased. Similarly, if the signal strength is found to be more, the HAGAR IC changes the control signal given to the BIAS pin of the HF Amplifier in such a way that the amplification in it is reduced. This way of controlling the signal strength is called the AGC or Automatic Gain Control. Thus the outputs obtained at Pin no.4 Of V501 (900 MHz GSM Band) and Pin no.6 of V500 (1800 MHz GSM Band) are then passed on to the 2nd DFBPF Z500 at its pins 1 & 3 respectively. As in the case of the 2nd DFBPF Z501 its function is again to pass the desired signals and block the undesired signals. So, Z500 gives much cleaner signals at its output pin 7 (900MHZ Band) and pin 5 (1800MHZ DCS Band).This signals then need to be passed through the balancing transformers T501 (GSM Band) & T500 (DCS Band) to ensure maximum signal transferring to the next stage, which is the RF or IF Processor IC, the HAGAR IC N500.

Test Points and their Purpose: Test Points in general are points or pads on PCB, brought out and placed in a convenient to access place, to TEST the status of certain points in the circuit, either by way of measuring voltage (could also be current or resistance in some cases) or observing the waveform to confirm or unconfirm the functioning of the circuit, by comparing the readings obtained of either the voltage or the waveform with a standard reference or ideal reading obtained at the same point in a perfectly working PCB or equipment under test. Obviously, if the reading obtained or the waveform observed is found to be identical to the reference reading or the waveform provided, the circuit of the preceding section can be assumed to be ok and one can proceed further to test in the following section/s to find or locate the fault and the faulty component.So the purpose of the Test point here is to check the circuit or for Fault Finding.

However, in addition to such test points, in mobile phones repairs, you will also come across test points brought out just to facilitate certain functions like unlocking or flashing only. No measurements are made on such points- this test points are normally connected to either the ground (or the -ve) point of the circuit or some other point of the circuit meant specifically for some manipulation of the circuit under certain mode of operation or service.

How do you find them on the PCB? You got to have the proper schematic diagram and the exact understanding of it to locate them or the actual picture of the PCB showing their exact location.

MEMORY ! MEMORY ! What is "Flash" in a Mobile Phone ? What is "BIOS" in a Computer?So, what is the BIOS? The BIOS, or Basic Input/Output System are the software code that operates your computer when the system is first turned on. I like to think of the BIOS as the master control of my computer, handling basic but critical functionality of the system. One primary function of BIOS is to direct the computer to execute various tasks before the operating system kicks in. For example, it tells your computer to start up the hard drive and load the operating system found there. Of course, users can change certain parameters of the BIOS to change how the computer operates. In the case of doing a fresh install of an operating system, you might have to change the BIOS settings to boot the computer from the CD rather than the hard drive.

Depending on the motherboard, the BIOS also controls certain functions on your system such as power management features, overclocking settings allowing you to change CPU frequencies to tweak desired performance from your system and a host of other unique functions. Various motherboards generally have their own unique BIOS functions and settings and are designed to get the best performance out of your specific system. Since the BIOS is made up of bits of code, they can also be changed or updated. This is why it is always important to check with your motherboard manufacturer to make sure you have the latest BIOS version running on your system. Otherwise, you might be missing out on new features or support for the latest devices.

When your computer first boots up, your BIOS runs automatically and most computer users generally have no reason to enter the BIOS to make changes unless 1. they are tweaking the performance of their system or enabling or disabling certain functionality or 2. something has gone wrong.

The BIOS is created by a motherboard or hardware manufacturer. The BIOS is what starts the computer after you turn on the power to your computer. Software programs, such as the Windows operating system, work with the BIOS to make your computer more user friendly. The BIOS program is stored in a Memory Device called EEPROM IC in a Computer generally.

In Mobile Phones , both this BIOS as well as the operating System is put in what is called the Flash IC in the form of Flash File. For Mobile Phones, the Flash Files are created by the respective Mobile Phone Manufacturers depending on the features which they want to incorporate in that particular model of the phone. So Naturally , the flash files for different phone models of the same manufacturer will be different. The Flash IC is a Memory Device which can accept new data or file into it by erasing the previous data stored in it by Erasing or deleting the old data within a Flash within no time practically and so is called a Flash IC !

Interesting .....isn't it ?

I think it will be very clear now that the Modern Day's Latest Mobile Phone is much like a Computer because it uses a Microprocessor (oftenly called the CPU) and so the working of the Mobile Phone may be easier to understand if we understand the working of the Computer, our Favorite PC, I mean !__________________

explanation of the basic theory of operation of a mobile phone in a very simple way :

Have you experienced the fact that in a music listened from a very long distance, the sounds of drums are less audible than the sounds of other sharp instruments like guitar ?Yesyesthis is because the sound of a drum is a low frequency signal and low frequencies cannot travel long distances easily while the high frequencies like the sound of guitar or other string instruments can !See how this is applied in the radio, tv and mobile technology for yourself. After all the mobile phone is also a radio telephone ! The broad meaning of the word "radio" is wireless. The principle of a mobile phone can be compared with that of a radio or a television system.The voice signal which is basically in the frequency range of 15 hertz to about 20 kilohertz (1kilohertz=1000 hertz)and is in the lowest freq.band in the normal frequency spectrum, which is required to be sent to the other mobile phone is first converted from analog to digital type of signal and is then mixed with a very high frequency signal in the range of hundreds of megahertz (1 megahertz = 1000kilohertz=1000x1000 hertz=1000000 hertz) in the mobile phone , this is called modulation, which means changing the audio signal by adding another very high frequency to it , the high frequency being used as carrier frequency to carry the voice or the audio signal. This is done to make it possible to be sent thro' air to the nearest tower of the service operator. The basic principle being that the high frequencies can travel longer distances easily. This was the transmitting part. (in radio or television systems, this is done at the transmitting end which is the radio or the tv station.)in the receiving part, the reverse (de-modulation) is required to be done. The received signal from the service operator's tower is required to be demodulated to remove the high frequency signal or the carrier frequency signal from the received signal, so that only digital audio signal is left out. In mobile phones, this digital audio signal is then converted to analog signal and after some amplification etc. Is sent to the speaker to be heard by the user. (in radio or television systems, this is done at the receiving end which is the radio or the tv itself !)both this transmitting (tx) and receiving (rx) functions are required to be carried out in the mobile phone itself and is done by what can be called the rf section of the mobile phone.

f we connect 2 cells of 1.2Volts in series as shown below, we get a voltage across them which is the sum of their respective voltages i.e.1.2v + 1.2v = 2.4v :

So in this way by connecting more than one cell of 1.2v in series we can get a battery with voltages in the multiples of 1.2v like 2.4v, 3.6v, 4.8v, 6v, 7.2v etc.A normal battery has only two terminals brought out of its casing. But the batteries used in Mobile Phones, many times have more than 2, at least 3 or even 4 (at the most) terminals brought out on its casing. You may wonder why so? It is very interesting to go into the details and know more about it. Though the charging circuit inside a mobile phone is generally designed with providing a very very safe charging voltage to the battery, it is made more perfect with the use of this additional terminals provided on the battery casing.

Abbreviations of some words

IMEI: International Mobile Equipment IdentityUEM: Universal Energy ManagerRAP3G: Radio Application Processor 3rd GenerationSRAM: Static Random Access MemoryLED: Light Emitted DiodLCD: Liquid CRYSTAL DisplayGSM: Global System for MobileGPRS: general packet radio servicesMMS : Multimedia Messaging ServicePDA Sets : Personal Digital Assistance SetsWAP : Wireless Application Protocol