White Paper - documents.swisscom.com · Technologies for Mobile Communications Technical Product Information White Paper Fast data transfer thanks to modern transfer procedures Version

White Paper

Technologies for Mobile Communications Fast data transfer thanks to modern transfer procedures

Technical Product Information Version 2.0

Technologies for Mobile Communications

Swisscom (Schweiz) AG Enterprise Customers Postfach CH - 3050 Bern

Gratisnummer 0800 800 900 Gratisfax 0800 800 905 E-Mail [email protected] Internet http://www.swisscom.ch/enterprise

Dokument WP Technologies for Mobile Communications Version 2.0 File WP_MobileTechnologies_E_v2_190115.doc

Datum 19.01.2015 Seite 2/18

Contents

1 Introduction to the topic .................................................................................................................. 3 1.1 Mobile communications and mobile usage of the Internet – a few facts ahead ...................... 3 1.2 New forms of working ............................................................................................ 4 1.3 Significant bandwidth increase ................................................................................. 4

2 Development of mobile communications ........................................................................................ 5 2.1 From analogue to digital “Natel” networks ................................................................... 5 2.2 Evolution of mobile data communications in GSM networks ............................................. 5 2.3 Evolution of mobile data communications in UMTS networks ........................................... 6 2.4 The fourth generation of cellular mobile communications: LTE .......................................... 9 2.5 Further development of LTE: LTE Advanced (LTE-A) or 4G+ ............................................... 13 2.6 A view to 2020: 5G ............................................................................................... 15

3 Wireless Local Area Networks (WLAN) ............................................................................................. 16

4 Glossary ........................................................................................................................................... 18

This White Paper was produced on the basis of the currently known parameters. It has in no way any obligation in law, but rather a pure informative character. If you have questions or comments on this White Paper, please contact us.





Datum 19.01.2015 Seite 3/18

1 Introduction to the topic

1.1 Mobile communications and mobile usage of the Internet – a few facts ahead

The trend towards mobile communications arrived in Switzerland a long time ago. Due to the high purchasing power and the openness for new technologies mobile services were and are used intensively. Swisscom customers would like to continue to accessing real-time information and sending data from their note-/netbooks or smartphones and tablets. And because the smartphone is practically the daily companion, a broad range of different usage scenarios are arising.

A few facts validate this trend:

80% of the Swiss population use the Internet several times per week (2013, BFS)

To access the smartphone, it is unlocked on average up to 80 times daily (Swisscom)

The expected rose of the worldwide mobile data volume will increase about six times between 2013 and 2018 (Analysis Mason)

The number of internet-capable devices will globally increase from 100 million in 2012 to 2 billion in 2021 (Analysis Mason)

The availability and the use of free of charge, internet-based communication services continues to increase. As a result of global networking, mainly the worldwide operating OTT provider (Over-The-Top) like Google, Amazon, Facebook, What's App etc. are profiting. Quantified it means:

The global OTT voice traffic comprised 750 billion minutes in 2013; in 2018 it will be 1.7 trillion minutes (Ovum)

In 2013 19 billion OTT messages were sent in Switzerland; in 2018 it will be 69 billion which corresponds to a yearly increase of 30%

43% of all Swiss smartphones already comprise an OTT messaging application and on 13% of all Swiss smartphones an OTT voice application was installed (Analysis Mason).

According to the Ericsson Mobility Report 2014

the number of worldwide connections used via smartphone is 2,7 billion by the end of 2014 which corresponds to a plus of 800 million,

approx. 90 % of the world population will use a mobile telephone in 2020;

in 2020 there will be worldwide approx. 8,4 billion mobile broadband connections and more than 6,1 trillion smartphones are expected.

Video applications stay as the main apps booster. Therefore the video data volume in mobile networks will multiply tenfold until 2020. 55 % of the whole data traffic will then consist of video data.





Datum 19.01.2015 Seite 4/18

1.2 New forms of working

The technical development of mobile communications has not only been extremely fast, it has also made new forms of working possible. On the one hand, people have already achieved a high degree of mobility as a result of the means of transportation that are available. On the other hand, flexible forms of working have only become possible as a result of modern communication means. The trend of working whenever and wherever one wants has risen sharply. This form of working best meets the current customer requirements in the commercial and private sphere. It makes it possible for people to do their work at the place where they happen to be, depending on the time of day or the order. This way of working also makes it possible to combine personal and business requirements in the best possible way. Swisscom has not only followed this trend as one of the largest employers in Switzerland, with its excellent network and IT infrastructure it has also enabled customers to introduce mobile workplaces. “Business Mobility” is therefore far more than just a buzzword. Largely unrestricted connectivity, coupled with high security for data transfer, provides real added value for users, be they our own employees or our customers.. Finally the attractiveness of an employer increases if flexible forms of working are supported and internal broadband networks are available.

1.3 Significant bandwidth increase

Even in fixed networks, there has been a high demand for bandwidth since the start of the new millennium, which Swisscom has met by hugely expanding its network. FTTH (Fibre To The Home) has made bandwidths of up to 1 Gbit/s and more possible. This trend is continuing in mobile communication networks. The transported data volume on Swisscom’s mobile networks is doubling each year and continues to grow. One reason is the high prevalence of smartphones plus note-/netbooks and tablet PCs. The popular smartphone has mutated into a multifunctional device that is suitable for practically all applications and yet still fits in a trouser pocket. The equally popular note-/netbooks and tablet PCs have in the most cases a WLAN module (Wireless Local Area Network) only, and some also have a radio module for connection to public mobile communication networks. With this type of equipment, safeguarded by special protocols and protective mechanisms, users can access all company data and their personal e-mails while out of the office

With a focus on customer requirements, Swisscom offers a broad technology portfolio. Its history, current offerings and future developments are presented in this White Paper.





Datum 19.01.2015 Seite 5/18

2 Development of mobile communications

2.1 From analogue to digital “Natel” networks

The term “Natel” is a registered trademark of Swisscom and a colloquial name for a mobile phone in Switzerland. In analogue mobile communications, it stood for national automobile telephone or (on introduction of the first digital generation, known as Natel D) for national telephone. A Natel network is therefore a network for mobile communications. The first analogue Natel A network appeared relatively late in Switzerland (1978), Natel B as the second generation came soon after (1983). Even though the transmission and receipt equipment was more compact, a 12 kg case was still needed to transport it. The end devices only became more compact – and slowly more affordable – with the auto-dialling network Natel C (as of 1987). Ten years after market launch, Swisscom welcomed the 100,000th customer. Natel C is based on the industry standard NMT (Nordic Mobile Telephone) with analogue voice transmission and digital transmission of switching and control information. With an acoustic coupler and analogue modem, smaller data volumes could already be slowly transmitted. The analogue networks Natel A to C can be grouped together as 1G (for first generation).

The transition to the age of digital mobile telecommunications was completed in 1993 with the 2G (2nd generation) at the Geneva Autosalon exhibition. Natel D – still in operation – is based on the European GSM standard (Global System for Mobile Communications). For the first time, a mobile network operated on a digital basis, and since then has been impressing customers with its low noise and interception security. In addition, thanks to roaming, customers can use their GSM mobile phones almost anywhere in the world.

2.2 Evolution of mobile data communications in GSM networks

The original GSM standard was highly focused on voice communications. Initially there were only a few options for mobile data communications and that at low speed. Thus CSD (Circuit Switched Data) permitted only a maximum of 9.6 Kbit/s, later increasing to 14.4 Kbit/s. CSD also took up a whole GSM channel (with only eight GSM channels per carrier frequency) and was inefficient from a wireless technology point of view. In addition, it did not match to the character of packet-oriented data communications. The improved, but still circuit-switched HSCSD service (High Speed Circuit Switched Data) did not become popular either. Here, up to four GSM channels of 14.4 Kbit/s were combined into one channel of up to 53.6 Kbit/s. From 2000, many GSM network operators offered HSCSD, but had little interest in its dissemination, because HSCSD took up wireless resources which were urgently needed for the still booming mobile voice communications. An improvement was only seen as of 2001 in the form of GPRS (General Packet Radio Service) as part of GSM generation 2.5 (GSM 2.5G). This was the first time a packet-switched mobile data service had been offered. Nevertheless, only 30 - 40 Kbit/s were possible – not really a speed to thrill customers, but still more than 9.6 Kbit/s. For the mobile transmission of larger data volumes during downloads EDGE (Enhanced Data Rates for the GSM Evolution) is a better choice. As evolution stage GSM 2.75G it offers until today though higher data rates than GPRS. But still it doesn’t really fulfil the high bandwidth requirements of modern end devices. Like GPRS, EDGE is part of the GSM standard and is available in almost all smartphones and mobile phones. It uses an optimised modulation procedure and is therefore often known as EGPRS (Enhanced GPRS). In practice, EDGE achieves bit rates of over 100 Kbit/s (the theoretical maximum is 256 Kbit/s).





Datum 19.01.2015 Seite 6/18

2.3 Evolution of mobile data communications in UMTS networks

The introduction of UMTS (Universal Mobile Telecommunications System) as the third mobile generation (3G) proceeded relatively unspectacular, at least on the Swiss market. Right at the start, the opportunity of mobile data communications was emphasised – a novelty. In addition a new device type was developed in the form of network cards, which were simply inserted in the notebook’s slot. Equipped with this, the notebook could exchange data via GSM/GPRS/EDGE, UMTS or WLANs. With the Mobile Unlimited© software, Swisscom also enabled notebook owners to communicate across networks without interruption thanks to “seamless handover” – to date an absolute first and a real competitive advantage. Initially, UMTS enabled speeds of up to 384 Kbit/s. Under hot-spot-like conditions (only a few users in the cell, high signal quality and no user movement) even 2 Mbit/s were possible. UMTS was a huge improvement versus GSM, particular for mobile data transfers.

Further development from UMTS 3G to 3.5G

Not only net- and notebooks, but especially smartphones have led to a real bandwidth demand boost. Their owners want to be constantly informed of what’s going on e.g. on Facebook or on news portals while they are on the move. In addition, smartphones enable field sales staff or engineers to be constantly connected to their company’s data. Decisions can be made more quickly, orders initiated more quickly.

To meet the growing demand for bandwidth, new standards are required for even faster data transmission. In addition, network expansions based on local requirement are unavoidable. Network standards, like the devices themselves, are constantly being developed and enhanced. While QPSK (Quadrature Phase Shift Keying) was still being used in UMTS 3G, UMTS generation 3.5G uses a powerful modulation procedure called 16 QAM (Quadrature Amplitude Modulation). The umbrella term HSPA (High Speed Packet Access) has become established here, and consists of two areas: HSDPA (High Speed Downlink Packet Access) for downloading data to the device, and HSUPA (High Speed Uplink Packet Access) for uploading data to the network (e.g. to a server). New types of coding were developed here, for example 16 QAM for HSDPA. While conventional UMTS uses one code per radio channel, with 16 QAM the transmission codes are used dynamically as a shared resource. The UMTS standard WCDMA 3GPP Release 5 developed by 3GPP (Third Generation Partnership Project) is based on a spreading of the transmission code, as a result of which up to 15 codes are available, depending on the spreading factor.





Datum 19.01.2015 Seite 7/18

The codes are allocated dynamically in an interval of 2 ms, i.e. 500 times per second (!!!). This operation can be thought of as a code multiplex dependent on time. Several users can use the same channel one after the other, using the same code. A participant can even use several codes simultaneously for transmission, which significantly improves the possible transmission speed. However, the bit rates shown in the table are theoretical values, but even in practice are still higher than

those for UMTS today. The reason for this is due to the characteristic of the TCP/IP network (Transmission Control Protocol/Internet Protocol), which actually stands in the way of mobile data connections. Most IP-based data services use TCP to control the flow of data packets. However, this protocol was primarily designed for fixed-network-based data connections, not for mobile connections with fluctuating bandwidth. As fixed-network connections hardly have any serious channel fluctuations, TCP flow control assumes that the channel quality is approximately constant during a transmission. If there are channel fluctuations during mobile data transmission, TCP reduces the number of transmitted data packets and thus also the bandwidth in order to meet the channel conditions. If the channel quality improves again, TCP increases the data volume again only slowly. Because e.g. fading effects in mobile networks can lead to severe reductions in channel quality, the maximum data speed of 384 Kbit/s was scarcely achieved in the first UMTS release. A severe reduction in channel quality means that the recipient does not receive a data package correctly, and it must therefore be transmitted a second time. As a result, the use of TCP in mobile networks leads to average latency times of 200ms to 300ms for UMTS, which can be problematic, depending on the application. Thanks to new mechanisms that enable HSDPA to react to fluctuating radio channels, the latency can be considerably reduced for an HSDPA radio channel. It is only around 100 ms, which is a huge improvement. The recent evolution step in UMTS networks is the area wide HSPA+ which offers up to 42 Mbit/s for downlink. For this, powerful software is installed in the mobile network that supports the higher-quality modulation type 64 QAM. New hardware and more powerful antennas with MIMO technology are also installed in all base stations. To transfer the high data volume to the network, the antenna locations are gradually made accessible with fibre optics.

For more information see:

http://www.3gpp.org/RAN





Datum 19.01.2015 Seite 8/18

Spotlight: Multiple Input, Multiple Output (MIMO)

Constantly increasing transmission speeds require not only new or optimised codecs, but also new antenna technologies. Wireless networks based on MIMO operate with several transmission and receipt antennas including complex digital signal processing. This improves the signal-to-noise ratio, which has a positive effect on data throughput and network coverage. This is particularly important in a non-line-of-sight coverage area, i.e. a receiving situation in which there is no line of sight between the fixed transmission antenna and the mobile receiver. With MIMO, the same information is sent and received in parallel via different antennas. As a result, the data throughput can be increased without new radio licences.

The basic technical principle of MIMO has already been used for years in WLANs. Space division multiplexing exploits the spatial statistical properties of a radio channel in multiple ways. This alone does not necessary increase the overall transmission power. However, transmission is constantly readapted to the changing features of the channels. All layers of the communication system must have a high degree of flexibility. One major challenge, for example, is implementing complex transmission and receiving systems for multiple antenna systems in the available hardware in such a way that they run perfectly under real-time conditions. The high computing power required means that high battery power is required in the device.

Raum-/Zeit-Abbildung

Functional principle of MIMO (Multiple Input, Multiple Output) (© R. Sellin)

The full potential of multiple antenna systems is revealed when an optimised complete system is used with several participants. The key to this is the intelligent assignment of resources to increase total system capacity, while always maintaining the total transmission power. Today fast mobile connections over intelligent codecs in networks like LTE, LTE-A and WLAN are inpensable without using multi-antenna systems.





Datum 19.01.2015 Seite 9/18

2.4 The fourth generation of cellular mobile communications: LTE

Introduction

The standardisation activities at 3GPP continue at an unchanged high speed. The fast development of technology becomes particularly obvious if the different standards for data communications in digital mobile networks and the appropriate releases since 1996 (GSM) are presented on a time axis. From the today’s point of view LTE and its extension LTE Advanced reside in the centre of all considerations.

Development of the 3GPP standards (© R. Sellin)

(Remark: The transmission speeds mentioned above are related to the download.)

The radio technology for 4G is called Long Term Evolution (LTE) and brings perceptible improvements when using mobile Internet connections. The fast mobile data transmission with download speeds up to 150 Mbit/s is building the clear focus of LTE, for instance for the mobile use of cloud services. Also applications such as video streaming at HD quality, video conferences and network games are profiting from the higher throughput as well as from the lower latency (approx. 20 ms). LTE is based on a new network architecture, amongst other elements with new hardware and (in major parts) a new core network. Wherever possible LTE base stations are built at already existing locations with sender facilities. The strict regulations regarding protection against radio emissions are continuously fulfilled. Between LTE sender and end device the multi-antenna technology MIMO is used (see text frame above). It has proved of value already in WLANs and at HSPA+ networks and improves the reception quality, extends the data throughput and reduces latency.

In addition to the enhancement of the transmission rates and the continued reduction of latency compared to UMTS/HSPA, LTE offers a faster connection set-up as an important differentiation characteristic. Amongst others, this is achieved by a stripped-down network architecture which reduces the number of signalling messages between the network elements. In consequence, the connection set-up lasts just 100 ms only which is advantageous for Voice over LTE (see next chapter below) and other applications.





Datum 19.01.2015 Seite 10/18

To compare: With HSPA one to two seconds were a common value. Furthermore, during the communication between sender and receiver, response times from 20 to 30 ms are thoroughly possible under optimised transmission field conditions.

In difference to GSM and UMTS, LTE is based completely on the Internet Protocol (IP). The All IP strategy is consequently transcribed in mobile networks from 4G on. Even in regions without LTE roll-out or in LTE networks without VoLTE (see below) making phone calls is possible. All LTE smartphones are produced as hybrid models and include a chip usable within UMTS and GSM networks. Additionally, USB sticks („surf sticks“) exist on the market, complemented by appropriate radio modules integrated into Note-/ Netbooks to guarantee fast data connections.

Network architecture

For LTE, major parts of the access and core network were designed completely new. The number of network nodes and interfaces was reduced due to the target of a simplified architecture. For LTE operators, the self-configuring base stations are advantageous because they are more reliable and more cost-efficient in operation and maintenance.

LTE Network architecture (simplified presentation) (© R. Sellin)

The LTE network architecture is also identified as Evolved Packet System (EPS). The EPS is sub-divided into the Evolved UMTS Terrestrial Radio Access Network (EUTRAN) and the Evolved Packet Core (EPC). Within the EUTRAN the mobile end devices are named User Equipment (UE). The function of the base station was derived from the UMTS network architecture. Thus it has the same designation as within UMTS networks: the eNode-B. In the LTE network architecture the base stations are connected with adjacent base stations via the X2 interface and with the core network. The X2 interface between the base stations allows a fast handover between the LTE radio cells.

The EPC is completely packet oriented and thus uses IP as a transport means. The Management Mobility Entity (MME) is responsible for the identification of users in the network and their localisation in the LTE network. For this purpose, the MME has access to the Home Subscriber Service (HSS). In case the end device





Datum 19.01.2015 Seite 11/18

has a valid SIM card, the user account is allocated to the Serving Gateway (SGW). From the SGW a connection exists to the PDN-GW (Packet Data Network Gateway) which in turn assigns an IP address to the end device and builds up a connection to the providers IP network. Additionally, the EPC comprises the PCRF (Policy and Charging Rules Function). It fulfils the billing for the user and allocates the characteristics and tariffs due to the service contract to him.

To handle the yearly doubling data traffic in mobile networks, a broadband connection from the base station to the EPC is required. For this purpose, predominately fibre networks are in use or (at locations without fibre connections or solitary locations) dedicated point-to-point radio systems are established. An omnidirectional sending LTE base station with three sectors each with 120° requires a bandwidth of almost 240 Mbit/s. This is multiple of what was considered to be sufficient for GSM as well as for UMTS. It gives proof the fibre networks come closer to radio station locations and to users – also in mobile networks.

Transmission technique and frequencies

LTE works with scalable and individual channels which allow several mobile end devices to transmit data at the same time. For this purpose the frequency spectrum is divided and allocated to single devices for a certain time. For the downlink the Orthogonal Frequency Division Multiple Access (OFDMA) is used. It divides the available frequency band in multiple narrow band channels. LTE therefore works with different unequally large frequency bands and allows the allocation of flexible bandwidths to the particular user. By this concept the maximum transmission power is generated from the available frequencies. To reach this target, special algorithms select the appropriate channels and consider the influence of the environment at the same time. Only the particular carrier is used for transmission which is the most suitable for the currently demanded service. For the uplink the SC-FDMA (Single Carrier Frequency Division Multiple Access) is used, a so-called one carrier access technique which is very similar to OFDMA. However a SC-FDMA show only little power fluctuations and allows less complex power amplifiers which extend the run-time of the rechargeable battery in the mobile devices.

LTE uses spatial differentiated data streams which lead in the LTE specification to up to four antennas in the base station and two antennas in the end device. For transmission, the sending signal is redirected to multiple sending antennas and is to be received in the end device by two antennas (MIMO). Via complex algorithms a signal with a higher quality is calculated from both received signals. Under ideal conditions a higher data throughput can be achieved because the paths for sending and receiving do not underlie the same interferences. Therefore signal loss and interferences are avoided or corrected more effective. SC-FDMA is also used in the WLAN standard IEEE 802.11n in a slightly modified form.

Worldwide more than 40 different frequencies are used for the respective national LTE networks. From a global view, 43% of the LTE users are transmitting signals at 1,8 GHz, 34% at 2,6 GHz and 11% at 800 MHz. By the end of 2013 worldwide 23 LTE frequencies were counted whereas for 2015 even 38 frequencies are forecasted (source: GSM Association/GSMA). The GSMA represents the interests of worldwide 800 mobile operators plus of 200 network suppliers. For these interest groups as well as for users the diversity of frequencies has cost driving effects because to develop globally working LTE products is almost impossible.

For the diversity of frequencies rises not only the network operator, but particularly the manufacturers of end devices and chips to great challenges. With every single frequency band to be supported by the chip the effort and costs are increasing. It is obvious that far not all worldwide existing LTE frequency bands can be supported by all LTE end devices. Depending on the country where the LTE services are offered, the end





Datum 19.01.2015 Seite 12/18

device runs on different frequencies. Thus it is possible that a LTE device works properly in one country, but not in another country because the locally used frequencies differ from each one another.

Voice over LTE (VoLTE)

As mentioned the LTE/4G networks currently support data traffic only. Telephone calls are led over Circuit Switched Fallback (CSFB) via GSM or UMTS networks. In the near future it will be possible to build up voice connections via LTE which can be considered as a kind of mobile Voice over IP (VoIP). This type is called Voice over LTE (VoLTE) and will be available from about summer 2015 in Swisscom’s LTE network. VoLTE will then be available within the whole mobile network of Swisscom. At locations without 4G/LTE coverage the calls in the access will be led via 2G/3G. Nevertheless the call control always remains at the VoLTE systems, the IP Multimedia Subsystem (IMS) and the application server.

VoLTE allows shorter call set-ups and offers an improved voice quality (HD Voice). In addition there is the possibility that Apps enrich the ordinary voice communication with comfortable additional features. During the phone call via LTE the user can continue to using high speeds. Therefore he can use additional data services in the LTE network in parallel to the phone call. The new technology offers further advantages. The spectral efficiency for the network and for the use of the frequency spectrum has been boosted once more compared to HSPA+ in UMTS networks. Additionally the power consumption is reduced because the energy consuming CSFB onto 3G/2G does not apply anymore.

Classical Over-The-Top-(OTT-)provider like Skype and Viber indeed are offering voice services on IP-based telecom networks. But they cannot guarantee any Quality of Service (QoS). Aside from that OTT provider cannot handle a seamless handover between multiple technologies (2G/3G/4G/PWLAN). Practically this means that a LTE voice connection is interrupted immediately when the LTE coverage once is interrupted during travelling. Moreover OTT applications do not assure certain regulatory terms like emergency calls and lawful interception (observation of the telecom traffic). Finally, specific plug-ins are required to make use of OTT apps in the first place.

By contrast VoLTE is integrated completely into the end devices and matches all qualitative and regulatory requirements. They are defined very similar to ordinary mobile voice telephony with the already mentioned advantage of the faster connection set-up and the increased voice quality with LTE. During the phone call the bandwidth for the data transmission is not reduced due to an exclusive connection build-up for VoLTE. It makes use of a dedicated bearer which is marked with a higher priority compared to the remaining data traffic (higher QoS).


http://www.3gpp.org/LTE

http://www.ltemobile.de/lte-technik/sprachuebertragung-im-lte-netz





Datum 19.01.2015 Seite 13/18

2.5 Further development of LTE: LTE Advanced (LTE-A) or 4G+

Due to the permanently increasing bandwidth demand both, a further extension of the network infrastructure and the use of new technology are indispensable. LTE Advanced (LTE-A) belongs to the latter, an enhancement of LTE. LTE-A offers once more higher data transmission rates, theoretically up to 1 Gbit/s, practically 300 Mbit/s (each at the downlink) in conjunction with a better spectral efficiency. Moreover, the standard specifies new modulation techniques and an again intensified multi antenna usage with up to eight antennas (8x8 MIMO).

LTE (3GPP Release 8/9) LTE Advanced (3GPP Release 10)

End device category 3 4 5 6 7 8

Downlink (Mbit/s) 100 150 300 300 300 1000-3000

Uplink (Mbit/s) 50 50 75 50 150 500-1500

MIMO links 2x2 2x2 4x4 2x2 diverse < 8x8 (DL), < 4x4 (UL)

Bandwidth (MHz) 1.4, 3, 5, 10, 15 und 20 20–100

Spectral efficiency 16,3 Bit/s per Hertz 30 Bit/s per Hertz

Carrier Aggregation (CA) no yes

Modulation technique in the downlink (DL)

QPSK/16QAM/64QAM 64QAM

Modulation technique in the uplink (UL)

QPSK, 16QAM

QPSK 16QAM 64QAM 64QAM

Comparison of both technologies: LTE and LTE-A

QPSK: Quadrature Phase Shift Keying, a phase modulation with two at 90° staggered carriers. The desired signal is extracted (at the sender) trough addition resp. trough subtraction (at the receiver) from the carrier signals.

MIMO: Multiple Input Multiple Output, multi antenna technology where the desired signal is sent on multiple channels and over multiple antennas in parallel.

QAM: Quadrature Amplitude Modulation with 16 Codes (16QAM) or 64 Codes (64QAM) respectively. QAM is a combination of amplitude and phase modulation.

A special feature of LTE-A is the Carrier Aggregation (CA). It serves the continued increase of the data rate per user. For LTE-A Swisscom uses currently three carrier frequencies, namely in the frequency bands 800, 1800 and 2600 MHz (in the future maybe also 2100 MHz). Within these frequency bands and depending on the local availability, more or less broad frequency blocks are allocated to the user (5, 10, 15 or 20 MHz) which are combined with CA. for example one can combine two blocks 10 MHz each at the frequencies 800 and 1800 MHz and offer 20 MHz to the user via CA. Another possibility could be a combination of two blocks with 15 MHz at 1800 MHz and 20 MHz at 2600 MHz which leads via CA to 35 MHz. The maximum data rate per user increases with CA by the number of available frequency blocks. Supplementary the whole data rate per radio cell increases too due to an improved exploitation of the resources.





Datum 19.01.2015 Seite 14/18

Principle of Carrier Aggregation (CA) within LTE-A (© Qualcomm/R. Sellin)

The use of LTE-A requires new end devices at least equal or more than category 6. The multi antenna technique (MIMO) with a number of data transmission paths as well as the use of CA demands the maximum computing power from the integrated circuits in the end devices. On the receiver side it is necessary to recompose different data streams as fast as possible to a consistent total signal with the target of a low latency. This is insofar formidable as signal reflections can lead to different running times and that signals can arrive with a few 100 Mbit/s at the receiver. Here the chip manufacturers have accomplished impressive developments.


http://www.3gpp.org/LTE-Advanced

http://www.ltemobile.de/lte-technik/lte-advanced

http://www.swisscom.ch/en/residential/mobile/mobile-network/4g-lte.html





Datum 19.01.2015 Seite 15/18

2.6 A view to 2020: 5G

Already for a few years the standardisation work for the fifth mobile communications generation (5G) is going on both in Asia and in Europe. The strong competition between Asia (namely China and South-Korea) on the one side and Europe (with first field tests in Japan and strong support from the EU) on the other side is remarkable. 5G will probably operate at 60 GHz because all other frequency bands are already occupied by other radio services. Frequencies at higher Gigahertz sectors may lead to characteristics like microcells, a difficult penetration of buildings and small coverage ranges.

Regarding 5G especially south-Korea seems to fear international competition. In the view of the local government other countries like China or the USA as well as a number of European countries are some steps ahead when it comes to investments into 5G technology. In fact South-Korea’s Chinese neighbour and European compoanies are both focussed. E.g. Ericsson already runs field tests with the operator DoCoMo in Japan using novel base stations. Owing to the high frequencies the partners are entering completely new territory. For 5G, Ericsson predicts for the year 2020 worldwide a 1000 times higher data capacity in mobile networks, 10 to a 100 times more mobile end devices, a five-times lower latency, 10 to a 100 times higher data transmission speeds by the end users and 10-times longer run-times of the battery.

In addition, the supplier and smartphone manufacturer Huawei wants to invest approx. 440 Mio. € until 2018 into the development of 5G networks. South-Korea intends to defeat these plans and wants to commercially start with 5G at the latest 2020. First field tests are scheduled for 2017, following the statements of the government. The South-Korean department of commerce intends to invest a billion € into 5G research and development and hopes to obtain additional funds from the private industry. It fits into the picture that the Samsung company is one of the pioneers in the 5G development. The whole Asian economic so far remains the driving force for new developments for radio communications which is a kind of tradition since the early UMTS times around the turn of the millennium.

The Europeans contrast these activities with own, amongst other activities with the EU-financed project METIS (Mobile and wireless communications Enablers for the Twenty-twenty Information Society). Here 29 partners with the time budget of 2900 man hours and a financial frame of 29 Mio. € are working together. On the supplier’s side the companies Alcatel-Lucent, Ericsson, Huawei, Nokia and Nokia-Siemens Networks (NSN) are engaged whereas on the operator’s side Deutsche Telekom, DoCoMo, Orange, Telecom Italia and Telefonica participate. 13 universities (RWTH Aachen, the Fraunhofer Institute/HHI and others) plus BMW as the representer of the car industry complement the register of all METIS members. After a first phase called „Usage scenarios and fundamental technology“ (until mid-2015) Phase 2 follows („Detailed concept development“, until the end of 2017).


www.metis2020.com





Datum 19.01.2015 Seite 16/18

3 Wireless Local Area Networks (WLAN)

Strictly speaking, the series 802.11x IEEE (Institute of Electrical and Electronics Engineers) standards are also categorised as mobile communications. This extensive series contains the technical specification for different Wireless Local Area Networks (WLAN). Their roots go back to the mid-1990s. Inspired by the success of the Ethernet (IEEE 802.3) and mobile communication in public networks, people had the idea of making the Ethernet interface mobile. The first standard from the 802.11x family was published in 1997. In subsequent years, 802.11a, g and h followed 802.11b. Other 802.11x standards are being continuously developed, including the still recent 802.11n. Contributions to IEEE have always had the best prospects of success if they are specified and submitted by the largest possible group. On the subject of 802.11n, a total of 27 companies from the WLAN area formed the Enhanced Wireless Consortium (EWC), led by Intel. EWC members include Apple, Atheros, Broadcom, Buffalo, Cisco, Conexant, D-Link, Lenovo, Linksys, Netgear, Sanyo, Sony, Ralink and Toshiba. The first draft of the IEEE 802.11n standard (Draft 1.0) was approved in January 2006. It then took a few years, and numerous further drafts, before the final standard was approved in September 2009.

IEEE 802.11n is an enhancement of the existing 802.11a/b/g standards. Several technologies are combined in the 802.11n standard. Here, the carrier signal is moved between four different phases. In addition, the data is coded in patterns that are easy to distinguish from each other and from noise. The 802.11a/g standards use technologies that split the radio range into several parallel transmission channels. The aim is to avoid interferences between neighbouring channels and to split the data streams across all channels, as a result of which local inferences are minimised. There are basically two ways of developing faster networks: More channels, or wider channels. The 802.11n standard uses both options and lures with bit rates of up to 600 Mbit/s. The use of licence-free frequency bands is still a problem. There, no further channels can be incorporated next to each other in the internationally assigned frequency bands for 2.4 GHz and 5 GHz. As a result, 802.11n overlays several channels on the same frequencies. The MIMO procedure used for this works with several transmitters and receivers with separate antennas.

The minimal differences between the physical distances between the transmitting and receiving antenna are used to differentiate the signals. As soon as the network has calculated the size of these differences, it can use mathematical means to disentangle the combined signals of each channel, even though they use the same frequency. In theory, every combination of two antennas can be used completely for data transmission, so that four spatial channels are available with two transmitting and two receiving antennas. The second measure with 802.11n is increasing the channel bandwidth. Instead of the previous 20 MHz wide channels, 40 MHz are used to again double the data throughput. However, the laws of physics cannot be completely bypassed here either: If every individual channel is twice as wide, the number of channels on a particular frequency band is halved. For existing users of these bands, there are therefore far fewer opportunities to switch to other channels.





Datum 19.01.2015 Seite 17/18

The practice with WLANs using EEE 802.11n gave proof that these WLANs are changing rapidly to the already high-in-use 2,4 GHz band as soon as signal problems appear in the 5 GHz band. This happens due to physical circumstances: The higher the frequency the worse or more difficult it becomes for the signal to saturate walls, panes and other obstructions. By the end of 2013 the IEEE standard 802.11ac was ratified. It relieves the busy 2,4 GHz band because it broadcasts in the 5 GHz band exclusively. WLAN environments in larger offices suffer increasingly under the trend „BYOD“ („Bring Your Own Device“). Indeed the busy 2,4 GHz band cannot cope with the impetus of private mobile devices and offers with a channel bandwidth of 20 MHz to little throughput. On the contrary, IEEE 802.11n offers enough spectrum with a channelled bandwidth of 80 MHz or 160 MHz and allows download speeds up to 7 Gbit/s, practically still up to 1,3 Gbit/s.

Overview to IEEE standards and drafts of the 802.11x series (© R. Sellin)


http://www.ieee802.org/11





Datum 19.01.2015 Seite 18/18

4 Glossary

3GPP Third Generation Partnership Project

CSD Circuit Switched Data

EDGE Enhanced Data Rates for the GSM Evolution

GPRS General Packet Radio Service

GSM Global System for Mobile Communications

HSCSD High Speed Circuit Switched Data

HSDPA High Speed Downlink Packet Access

HSPA High Speed Packet Access

HSUPA High Speed Uplink Packet Access

IEEE Institute of Electrical and Electronics Engineers

IP Internet Protocol

LTE Long Term Evolution

LTE-A LTE Advanced

MIMO Multiple Input, Multiple Output

QAM Quadrature Access Modulation

QPSK Quadrature Phase Shift Keying

SIM Subscriber Identity Module

SIP Session Initiation Protocol

UMTS Universal Mobile Telecommunications System

VoLTE Voice over LTE

VPN Virtual Private Network

WLAN Wireless Local Area Network

Documents

White Paper - documents.swisscom.com · Technologies for Mobile Communications Technical Product Information White Paper Fast data transfer thanks to modern transfer procedures Version