CDMApptFinal (2).ppt

ContentsHistory of CDMA Evolution path of CDMA

College of Telecommunications and Information Technology 1

Unit one

CDMA History and Evolution

History of CDMA• CDMA was developed originally by

Qualcomm and enhanced by Ericsson.• CDMA is characterized by high capacity

and small cell radius, employing spread-spectrum technology and a special coding scheme.

College of Telecommunications and Information Technology

2

History…• CDMA was adopted by the Telecommunications

Industry Association (TIA) in 1993. • The first CDMA cellular mobile communication

system was commissioned in Hong Kong in 1995.

• In September 1998, only three years after the first commercial deployment , there were 16 million subscribers on cdmaOne systems worldwide.


3

History…• By May 2001 there were 35 million

subscribers on cdmaOne systems worldwide and there are now 60 million.

• QUALCOMM owns a substantial portfolio of CDMA patents.


4

11GG 22GG 33GG

Analog cellular

DDiiggiittaall cceelllluullaarr DDiiggiittaall cceelllluullaarr

VVooiiccee VVooiiccee //ddaattaa VVooiiccee // hhiigghh ssppeeeedd ddaattaa

AAMMPPSS CCDDMMAA 11XXRRtttt CCDDMMAA22000000

TTAACCSS GGSSMM GGPPRRSS WW__CCDDMMAA

8800’’ 11999922 11999999 22000011 22000033

Evolution of Mobile Communications System

AMPS: Advanced Mobile Phone SystemTACS: Total Access Communication SystemGPRS: General Packet Radio Services


5

Evolution of CDMA2G

FL 3.09Mbps PDRL 1.8 Mbps PD

2.5G 3G

Voice

cdmaOneIS-95-A

••

• High Capacity Voice• 153 kbps PD• RF Backward

Comp.

CDMA20001X

CDMA20001X Rel A

• 2.4 Mbps PDRF Backward Comp.

CDMA2000 1xEV-

IS-95-BKoreaJapan

• Voice• 64 kbps Packet• RF Backward

Compatible

••• Backward Comp.

CDMA2000 1xEV- DO Rel

• FL 3.09 Mbps PD• RL 1.8 Mbps PD• Backward Comp.

CDMA2000 Rel D

cdmaOneIS-95-A

•

cdmaOneIS-95-A

•14.4 kbps CSD

•••

CDMA20001X

•••

CDMA20001X Rel. 0

• 307.2 kbps Packet• Backward Comp.

CDMA20001X Rel A

CDMA20001X Rel.A

•

CDMA2000 1xEV-

•

CDMA2000 1xEVDO Rel. 0

IS-95-BKoreaJapan

•••

IS-95-BKoreaJapan

•••

••

CDMA2000 1xEV- DO Rel

••

CDMA2000 1xEVDO Rev.A

•••

CDMA2000 1xEVDV Rel D

•••

D

•


6

Unit TwoBasic Principles in CDMA

ContentsSpread spectrum technology principlesSpeech Coding TechnologyChannel Encoding Technology


7

Defining Our Terms• CDMA Channel or CDMA Carrier or CDMA Frequency

– Duplex channel made of two 1.25 MHz-wide bands of electromagnetic spectrum, one for Base Station to Mobile Station communication (called the FORWARD LINK or the DOWNLINK) and another for Mobile Station to Base Station communication (called the REVERSE LINK or the UPLINK)

– In 800 Cellular these two simplex 1.25 MHz bands are 45 MHz apart– In 1900 MHz PCS they are 80 MHz apart

• CDMA Forward Channel

– 1.25 MHz Forward Link

• CDMA Reverse Channel– 1.25 MHz Reverse Link

• CDMA Code Channel– Each individual stream of 0’s and 1’s contained in either the CDMA Forward Channel

or in the CDMA Reverse Channel– Code Channels are characterized (made unique) by mathematical codes– Code channels in the forward link: Pilot, Sync, Paging and Forward Traffic channels– Code channels in the reverse link: Access and Reverse Traffic channels

45 or 80 MHz

CDMA CHANNELCDMA

ReverseChannel 1.25 MHz

CDMAForwardChannel 1.25 MHz

Spread Spectrum In CDMA

• The spread spectrum communications technology is an information transmission mode.

• The frequency bandwidth, occupied by signals, is far larger than the minimum bandwidth required for the information to be transmitted.

Spread Spectrum In CDMA• The spread width of the frequency band is

realized by means of coding and modulation.

• It is independent with the transmitted information data.

Spread Spectrum In CDMA…ORIGINATING SITE DESTINATION

SpreadingSequence

SpreadingSequence

InputData

RecoveredData

Spread Data Stream

Definition: Spread spectrum techniques ,employ a transmission bandwidth that is several orders of magnitude greater than the minimum required signal bandwidth.

Sender combines data with a fast spreading sequence, transmits spread data streamReceiver intercepts the stream, uses same spreading sequence to extract original data


11

SHANON Formula

Spread Spectrum…

Where, C is capacity of channel, b/s B is signal bandwidth, Hz S is average power for signal, W N is average power for noise, W

C=B*log2(1+S/N)

It is the basic principle and theory for spread spectrum communications.


12

Spread Spectrum…

User 1

Code 1

Composite

Time Frequency

+=

Direct Sequence CDMA


13

CDMA a Spread-Spectrum System

Traditional technologies try to squeeze the signal into the minimum required bandwidth

Direct-Sequence Spread spectrum systems mix their input data with a fast spreading sequence and transmit a wideband signal

The spreading sequence is independently regenerated at the receiver and mixed with the incoming wideband signal to recover the original dataSpread Spectrum Payoff:

Processing Gain

Spread SpectrumTRADITIONAL COMMUNICATIONS SYSTEM

SlowInformation

Sent

TX

SlowInformationRecovered

RX

NarrowbandSignal

SPREAD-SPECTRUM SYSTEM

FastSpreadingSequence

SlowInformation

Sent

TX

SlowInformationRecovered

RX

FastSpreadingSequence

Wideband Signal

Spread Spectrum…


15

1.25 MHz30 KHz

Power is “Spread” Over a Larger BandwidthMATHHAMMER

MATHHAMMER

Spread Spectrum…


16

Many code channels are individually“spread” and then added together tocreate a “composite signal”

De-spreading…

• Any data bit stream can be combined with a spreading sequence• The resulting signal can be de-spread and the data stream

recovered if the original spreading sequence is available and properly synchronized

• After de-spreading, the original data stream is recovered.

ORIGINATING SITE DESTINATION

SpreadingSequence

SpreadingSequence

InputData

(Base Band)

RecoveredData

(Base Band)

Spread Data Stream(Base Band + Spreading Sequence)

Multiple codes

• Multiple spreading sequences can be applied in succession and then reapplied in opposite order to recover the original data stream.

• The spreading sequences can have different desired properties.• All spreading sequences originally used must be available in proper

synchronization at the recovering destination.

SpreadingSequence

ASpreadingSequence

BSpreadingSequence

CSpreadingSequence

CSpreadingSequence

BSpreadingSequence

A

InputDataX

RecoveredDataX

X+A X+A+B X+A+B+C X+A+B X+ASpread-Spectrum Chip StreamsORIGINATING SITE DESTINATION

Analogy…

• Whether in shipping and receiving or in CDMA, packaging is extremely important!

• Cargo is placed inside “nested” containers for protection and to allow addressing.

• The shipper packs in a certain order, and the receiver unpacks in the reverse order.

• CDMA “containers” are spreading codes.

FedE

xData Mailer

FedE

x

DataMailer

Shipping Receiving

• Spreading code chip speed is 1.2288Mc/s.• Spreading codes used:

Forward link—Walsh code & Short PN Reverse link—Long PN

Spreading Codes in CDMA

Spreading code selection is the key of spread Spectrum modulation!

Walsh Code Definition• The Walsh function is named after Walsh, the

mathematician who proved it an orthogonal function in 1923.

• Walsh code is an orthogonal square matrix. It is just composed of +1(0) and –1(1).


21

0110

1100

1010

0000

10

000

Hn Hn

H2n = ___

Hn HnH1 H2 H4

Walsh Codes• 64 Sequences, each 64 chips long

– A chip is a binary digit (0 or 1)• Each Walsh Code is Orthogonal to

all other Walsh Codes– This means that it is possible to

recognize and therefore extract a particular Walsh code from a mixture of other Walsh codes which are “filtered out” in the process

– Two same-length binary strings are orthogonal if the result of XORing them has the same number of 0s as 1s

WALSH CODES # ---------------------------------- 64-Chip Sequence ------------------------------------------ 0 0000000000000000000000000000000000000000000000000000000000000000 1 0101010101010101010101010101010101010101010101010101010101010101 2 0011001100110011001100110011001100110011001100110011001100110011 3 0110011001100110011001100110011001100110011001100110011001100110 4 0000111100001111000011110000111100001111000011110000111100001111 5 0101101001011010010110100101101001011010010110100101101001011010 6 0011110000111100001111000011110000111100001111000011110000111100 7 0110100101101001011010010110100101101001011010010110100101101001 8 0000000011111111000000001111111100000000111111110000000011111111 9 010101011010101001010101101010100101010110101010010101011010101010 001100111100110000110011110011000011001111001100001100111100110011 011001101001100101100110100110010110011010011001011001101001100112 000011111111000000001111111100000000111111110000000011111111000013 010110101010010101011010101001010101101010100101010110101010010114 001111001100001100111100110000110011110011000011001111001100001115 011010011001011001101001100101100110100110010110011010011001011016 000000000000000011111111111111110000000000000000111111111111111117 010101010101010110101010101010100101010101010101101010101010101018 001100110011001111001100110011000011001100110011110011001100110019 011001100110011010011001100110010110011001100110100110011001100120 000011110000111111110000111100000000111100001111111100001111000021 010110100101101010100101101001010101101001011010101001011010010122 001111000011110011000011110000110011110000111100110000111100001123 011010010110100110010110100101100110100101101001100101101001011024 000000001111111111111111000000000000000011111111111111110000000025 010101011010101010101010010101010101010110101010101010100101010126 001100111100110011001100001100110011001111001100110011000011001127 011001101001100110011001011001100110011010011001100110010110011028 000011111111000011110000000011110000111111110000111100000000111129 010110101010010110100101010110100101101010100101101001010101101030 001111001100001111000011001111000011110011000011110000110011110031 011010011001011010010110011010010110100110010110100101100110100132 000000000000000000000000000000001111111111111111111111111111111133 010101010101010101010101010101011010101010101010101010101010101034 001100110011001100110011001100111100110011001100110011001100110035 011001100110011001100110011001101001100110011001100110011001100136 000011110000111100001111000011111111000011110000111100001111000037 010110100101101001011010010110101010010110100101101001011010010138 001111000011110000111100001111001100001111000011110000111100001139 011010010110100101101001011010011001011010010110100101101001011040 000000001111111100000000111111111111111100000000111111110000000041 010101011010101001010101101010101010101001010101101010100101010142 001100111100110000110011110011001100110000110011110011000011001143 011001101001100101100110100110011001100101100110100110010110011044 000011111111000000001111111100001111000000001111111100000000111145 010110101010010101011010101001011010010101011010101001010101101046 001111001100001100111100110000111100001100111100110000110011110047 011010011001011001101001100101101001011001101001100101100110100148 000000000000000011111111111111111111111111111111000000000000000049 010101010101010110101010101010101010101010101010010101010101010150 001100110011001111001100110011001100110011001100001100110011001151 011001100110011010011001100110011001100110011001011001100110011052 000011110000111111110000111100001111000011110000000011110000111153 010110100101101010100101101001011010010110100101010110100101101054 001111000011110011000011110000111100001111000011001111000011110055 011010010110100110010110100101101001011010010110011010010110100156 000000001111111111111111000000001111111100000000000000001111111157 010101011010101010101010010101011010101001010101010101011010101058 001100111100110011001100001100111100110000110011001100111100110059 011001101001100110011001011001101001100101100110011001101001100160 000011111111000011110000000011111111000000001111000011111111000061 010110101010010110100101010110101010010101011010010110101010010162 001111001100001111000011001111001100001100111100001111001100001163 0110100110010110100101100110100110010110011010010110100110010110

Walsh Codes EXAMPLE:• Correlation of Walsh Code #23 with Walsh Code #59#23

0110100101101001100101101001011001101001011010011001011010010110

#59 0110011010011001100110010110011010011001011001100110011010011001

XOR 0000111111110000000011111111000011110000000011111111000000001111

• Correlation Results: 32 1’s, 32 0’s: Orthogonal!!

0 1 2 3 4 5 6 7 1 1

8 9 0 11 1 1 12 3 4 5

1 1 1 16 7 8 9

2 2 2 20 1 2 3

2 2 2 24 5 6 7

2 2 3 38 9 0 1

3 3 3 32 3 4 5

3 3 3 36 7 8 9

4 4 4 40 1 2 3

4 4 4 44 5 6 7

4 4 5 58 9 0 1

5 5 5 52 3 4 5

5 5 5 56 7 8 9

6 6 6 60 1 2 3

0123

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

4567

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

89

1011

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

12131415

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

16171819

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

20212223

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

24252627

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

28293031

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 0 1 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

32333435

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

36373839

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

40414243

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

44454647

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

48495051

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

52535455

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

56575859

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

60616263

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 0 1 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

Walsh Code Table

Walsh Code…

• A Mobile Station receives a Forward Channel from a sector in a Base Station.

• The Forward Channel carries a composite signal of up to 64 forward code channels.

• Some code channels are traffic channels and others are overhead channels.

• A set of 64 mathematical codes is needed to differentiate the 64 possible forward code channels.


25

Walsh Code…• The Walsh code is also used to perform

orthogonal modulation on the reverse link.• Its use is chanalization.• Forward channels include Pilot, Sync,

Paging, and Forward Traffic channels.

Walsh Code…• Pilot channel is assigned Walsh code 0.• Sync channel is assigned Walsh code 32• Paging channel can be assigned Walsh

codes 1 to 7.• Forward traffic channels are assigned

random Walsh codes from the 55 (or 61 from paging channels) which are left.

Short PN• If we now have two BTS transmitting a set of

forward code channels each, how can we identify between the signals of the two?

• For this purpose we use the Short PN Sequence.

• The short PN is also used for digital modulation; QPSK modulation on the forward link and OQPSK on the reverse link.

Short PN Sequences

• Together, they can be considered a two-dimensional binary “vector” with distinct I and Q component sequences, each 32,768 chips long

• Each Short PN Sequence (and, as a matter of fact, any sequence) correlates with itself perfectly if compared at a timing offset of 0 chips

• Each Short PN Sequence is special: Orthogonal to a copy of itself that has been offset by any number of chips (other than 0)

IQ

32,768 chips long26 2/3 ms.

(75 repetitions in 2 sec.)

IQIQ

100% Correlation: All bits = 0

Short PN Sequence vs. Itself @ 0 Offset

IQIQ

Orthogonal: 16,384 1’s + 16,384 0’s

Short PN Sequence vs. Itself @ Any Offset

Unique Properties:

The two Short PN Sequences, I and Q, are 32,768 chips long

Short PN…

1 0010 0110 1101 1011 0100 1011 0110 1111 1111 110

10 0 00 0100 100

1 1001 000

0 100

p1 p2 p3 p4

p4 p5 p2 p3

p2 p3

p4

p5 = p1 + p4

p4

Short PN…The PN sequences are deterministic and periodic.

– The length of the generated string is 2n-1, where “n” is the number of elements in the register

– The number of ones in the sequence are equal to the number of zeros plus 1

Short PN…

• Each Sector in each Base Station is transmitting a Forward Traffic Channel containing up to 64 forward code channels.

• These Short PN Sequences can be used in 512 different ways in a CDMA system. Each one of them constitutes a mathematical code which can be used to identify a particular sector.


32

A B

Up to 64Code Channels

Up to 64Code Channels

Long PN• The main function of the Long PN

Sequence is found on the reverse link.• Since all users can be on the same

frequency, it is easy to confuse for the BTS.

• The long PN is used to identify and differentiate the users on the reverse channel.

Long PN Sequence

• Each mobile station uses a unique User Long Code Sequence generated by applying a mask, based on its 32-bit ESN, to the 42-bit Long Code Generator which was synchronized with the CDMA system during the mobile station initialization.

• Generated at 1.2288 Mcps, this sequence requires 41 days, 10 hours, 12 minutes and 19.4 seconds to complete.

• Portions of the User Long Codes generated by different mobile stations for the duration of a call are not exactly orthogonal but are sufficiently different to permit reliable decoding on the reverse link.

Long Code Register (@ 1.2288 MCPS)

Public Long Code Mask (STATIC)

User Long CodeSequence

(@1.2288 MCPS)

1 1 0 0 0 1 1 0 0 0 E S N

AND

=S U M

Modulo-2 Addition

Long PN…• The CDMA system must be

able to identify each Mobile Station that may attempt to communicate with a Base Station.

• One binary digit sequence called the Long PN Sequence (or Long PN Code) is defined for the purpose of uniquely identifying each possible reverse code channel.


35

RV Trafficfrom M.S.

#1837732008 RV Trafficfrom M.S.

#1997061104

RV Trafficfrom M.S.

#1994011508System AccessAttempt by M.S.

#2000071301(on access channel #1)

Coding in CDMA

• Data transmission efficiency has been a critical issue in the development of telecommunication networks for a long time.

• so it is extremely important to use different speech coding techniques.

Coding…• To date, researchers have been studying

this issue in two ways.• Study new modulation methods and

techniques to improve channel transmission bit rate.

• Compress source encoding bit rate.

Speech coding…

Speech coding is essential because we have to use the available bandwidth efficiently.

current CDMA systems employ an effective voice encoding technique, Qualcomm Code Excited Linear Prediction (QCELP).

The other kind of coding widely used is EVRC(Enhanced variable rate coding)


38

Channel Encoding Technology

Due to the peculiarity of mobile communication systems, high requirement is imposed on channel encoding.

The aim of channel encoding is to minimize error during transmission.

Some of the encoding technologies are:Convolutional Viterbi Turbo


39

Unit ThreeCDMA Network and Its

Elements

ContentsNetwork Architecture Description of Network elements


40

CDMA Network Architecture

2G/3G Terminals

Abis

Abis

Abis

PSTN/PLMN

BSC/ PCF (1X)

Internet

Router Router

IP

IP

BTS （ IS-95）

BSC （ IS-95）

AbisE1

Um

IS95

Um

IS2000E1 STM-1

E1 STM-1

Ethernet

MSC/VLR HLR/AUC

PDSN/FA

AAA

HA

OMC

SC

WINBTS （ IS-9

5）

BSC/ PCF (1X)

BTS （ 1X）

BTS （ 1X）

E1

Server

Ethernet

41College of Telecommunications and

Information Technology

Description of Network elements

• BTS:BTS is in charge of wireless transmission.

• The BTS is the network element responsible for maintaining the air interface and minimizing the transmission problems.

Air interface signalingSpeech processingThe base station can contain several TRXs

(Transceivers)


42

Description…

• The BSC is the central network element that controls the radio network. The important functions of the BSC are:Connection establishment between the AT and

the core network elements.Statistical data collection and control of the

BTS’s and the AT’s.Signalling support in the air and with the core

network elements.Mobility management:


43

Description of Network elements• MSCe (MSC emulation)

– The MSCe (MSC emulation) is a set of multiple logic functional entities.

– It supports mobility management, and provides call control, connection, VLR and some service functions.

– It is the core device providing call control and service for CS real-time voice/data services in this phase.



Description…• MGW (Media gateway )

– The MGW (Media gateway ) provides the packet switching environment in the core network , and the circuit switching environment in the PSTN with the support for bearer services.

• HLRe (HLR emulation)– On the base of HLR in 2G, the IP signaling

interface is added to the HLRe to manage the user’s voice service , data service features , user location and accessibility information.



Unit FourUnderstanding CDMA channels

ContentsDefining Channel term in CDMAChannel Structures

CDMA IS-95 and CDMA2000-1xCDMA2000-Ev-DO


46

Defining Channel term in CDMA

• Channel: An individually-assigned, dedicated pathway through a transmission medium for one user’s information.

• The transmission medium is a resource that can be subdivided into individual channels according to the technology used.


47

FrequencyTime

Power

FrequencyTime

Power

FrequencyTime

Power

FDMA

TDMA

CDMA

.

Defining Channel…–Code Channels are characterized (made unique)

by mathematical codes–Code channels in the forward link: Pilot, Sync,

Paging and Forward Traffic channels–Code channels in the reverse link: Access and

Reverse Traffic channels –The bandwidth of a CDMA channel is constant

and it is 1.25MHz.


48

Channel Structures in CDMA IS-95 and 2000-1x


49

Pilot Channel


50

Transmitted constantly by Base station to provide a reference for all mobile stations.All Base Stations share the same Short PN sequence, but are distinguished by the different phase offsets. Used for comparison of Signal strength between different base stations to decide when to perform the Hand off.

Sync Channel


51

(Acquired Pilot)

Sync Channel

Used to provide Basic system parametersUsed during system acquisition stageBit rate is 1.2 kbpsUses Walsh Code 32

Paging Channels


52

Paging Channel

The Paging channel carries information to allow the network to supply display information to be displayed by the MSThere is one paging channel per sector per CDMA carrierThe Paging Channel uses Walsh code - 1Two rates are supported: 9.6 kbps and 4.8 kbps

Reverse Access Channels


53

Access channel

Used by the mobile station to:– Register with MSC (Power On)– Originate a call– Respond to a Paging Channel message– Has a fixed data rate of 4.8 kbps

Each Access Channel is associated with only one Paging Channel

Reverse Traffic Channels


54

Reverse Traffic Channel

Used when a call is in progress, to send:–Voice traffic from the subscriber–Response to commands/queries from the base station –Requests to the base station

Forward Channel Structure of Ev-Do

ControlMediumAccessControl

Pilot Traffic

ReverseActivity Channel

ReversePower

Control(RPC)

Forward

DRC Lock


55

Sharing the Forward Traffic Channel


56

DRCLockDRCLockDRCLockDRCLock DRCLockDRCLock DRCLockDRCLock

DRCLockDRCLock DRCLockDRCLock DRCLockDRCLock DRCLockDRCLock

Forward Link Summary Forward link transmission is organized as

26.66…ms frames. 1 frame=16 slots, where 1 slot=2048 chips=1.67 ms.

The transmission rate (38.4 kbps ~ 2457.6 kbps) is the rate requested by AT,

Channels are mostly in TDM mode. Traffic data are dedicated to a single AT at

any given instant of time.


57

Reverse Channel Structure


58

Reverse Link Summary 1 packet = 26.67 ms, 1 slot = 2048

chips, 1 frame=16 slots Supporting data rates from 9.6k to

153.2K. Channels are in CDM mode Two main channels Traffic channel and

Access channel. Traffic channel = Pilot + MAC + Data +

ACK Access channel = Pilot + Data Supporting reverse closed & open loop

power controlsCollege of Telecommunications and

Information Technology59

Unit FiveCDMA Key Technologies

ContentsPower controlHandoff


60

Power control in CDMA

There are four types of power control in CDMA

- Reverse open loop power control

- Reverse closed loop power control

- Reverse outer loop power control

- Forward traffic channel power control


61

Reverse Open Loop Power Control

• The mobile station makes a coarse initial estimation of the required transmit power, based upon the total received power.


62

Mobile BTSReverse Open Loop

Power Control

Reverse Closed Loop Power Control


63

Mobile BTSSignal StrengthMeasurement

Setpoint

or

Reverse Closed LoopPower Control

Compensates for asymmetries between the forward and reverse pathsEach command requests a 1dB increase or decrease of the mobile station transmit powerTransmitted 800 times per second (i.e power control bit is transmitted every 1.25ms )

Reverse Outer Loop Power Control


64

FER

Mobile BTS BSCReverse Outer

Loop Power Control

Signal StrengthMeasurement

Setpoint

orReverse Closed Loop

Power Control

Most gradual form of reverse link power control

–Setpoint is varied according to the FER on the Reverse Traffic Channel

–Sampled at a rate of 50 frames per second (20 ms / frame)

–Setpoint adjusted every 1-2 seconds

Forward Traffic Channel Power Control


65

The base station slowly decreases power to each mobile station. As the FER (determined at the mobile station) increases, the mobile station requests a Forward Traffic Channel power increase.

Summary of All Power Control Mechanisms


66

All types of power control work together to minimizes power consumption at the mobile stations.This increases the overall capacity of the system transmit power.

Handoff in CDMA


67

Handoff is the process by which a mobile station maintains communications with the Mobile Switching center (MSC), when traveling from the coverage area of one base station to that of another.Handoffs keep the call established during the following conditions:

–Subscriber crosses the boundaries of a cell

–Subscriber experiences noise or other interference above a specified threshold

CDMA Handoff Classification


68

Duringa Call

Idle Handoff

Soft Handoff

Softer Handoff

CDMA-to-CDMA Handoff

Inter-System Soft Handoff

CDMA-to-Analog Handoff

While in the Idle State

PN 104

PN 108

A

Paging Channel Msgs

Sync Channel Msg

104108

Ec/Io

It’s neither soft nor hardhandoff!

CDMA Idle Handoff


69

PN 104

PN 108

APaging Channel M

sgs

Sync Channel Msg

104108

Ec/Io >3dB

CDMA Idle Handoff…


70

Soft Handoff


71

Cell SiteB

Cell SiteA

PSTNMSC

Between sectors of different cells

Soft Handoff: the mobile station starts communications with a target base station without interrupting communications with the current serving base station.

Can involve up to three cells simultaneously and use all signals

Softer Handoff


72

alpha

beta

gamma

Handoff is between sectors of the same cellMay happen frequentlyMSC is aware but does not participateSignals received at both sectors can be combined for improved quality

How many CE will be used?

Inter-System Soft Handoff


73

Mobile Station starts communications with a new cell controlled by a different BSC while still communicating with the cell controlled by the source BSC.

CDMA-to-CDMA Hard Handoff


74

A(ƒ1)

PSTN MSCBSC

B(ƒ2)

A

PSTNMSCBSC

B

MSCBSC

T1 or E1 LinksTIA/EIA-41D

Between cells operating on different frequencies

Between cells that could be on the same frequency, but which are subordinated to different MSC

Unit Six Interfaces and Protocols

Contents InterfacesProtocols and signalingTypical CDMA Network Architecture


75

Interfaces in CDMA 20001x


76

Interfaces of 1xEVDO

Source Access Network (AN)

Target Access Network (AN)

Access Terminal (AT)

AN AAA

PDSNPCF

A8

A9

A10

A11

A12A13Air Interface

signaling

service


77

Interfaces…

• The A1 interface carries signaling information between BSC and MSC.

• The A2 interface mainly carries 64/56K PCM between BSS and MSC.


78

Interfaces…

• A3 interface is used to support the soft handoff(interconnection between BSCs required) between BSSs when the MS is in the traffic channel status. A3 interface is divided into two parts: A3 signaling interface and A3 traffic interface.


79

Interfaces…

• A7 interface is used to support the handoff between BSSs when the MS is not yet under the control of traffic channel status, and support the control stream when the MS undergoes soft handoff between BSSs and new service needs to be established.


80

Interfaces…

• A8 & A9 interfaces are adopted to carry service data and signaling respectively between BSC and PCF.

• A10 & A11 interfaces are adopted to carry service data and signaling respectively between PCF and PDSN.


81

Interfaces…

• A12 interface carries signaling information of access authentication (only include 3 messages: access request, access accept, and access reject).

• A13 interface exchanges signaling when AT is roaming between source AN and target AN.


82

UDP

Protocols & signaling

IP

TCP SCTP

SIP/SIP-T H.248

SCCP

SUA M3UA

RTP BSSAP MAP



Protocols & signaling…SignalingSignaling•It is the dialog language for the communication between various parts of the telecom network. •Signaling system includes a set of signaling and operation procedure.

•Signaling system is the collection of software and hardware which generate 、 transmit 、 receive and recognize the signaling. 84


Signaling System SS7 is the predominant signaling system for the Public Switched Telephone Network (PSTN) and also Public Land Mobile Networks (PLMN).

SS7 defines the procedures for setting-up, managing and clearing down calls between subscriber(circuit-related signaling ), as well as non circuit-related signaling.

Protocols & signaling…




MSCe MSCe

MGW

MGW

MGW

Control Signalin

g Over IP

H.248 H.248

Media Over

IP

H.248 ： used in MSCe to control the MGW implement voice bearing on the packet network. They reflect the idea of separating control function from the media conversion function.

MGW

MGW

What is H.248?




• Command is used to operate and manage logical entities (context and terminations). The protocol defines eight commands, of which the majority is used for the MGC (MSCe) to control MG (MGW).

• All of the commands in one action control the same context.




Add

Modify

Subtract

Move

AuditValue

AuditCapabilities

Notify

ServiceChange

MSCe MGW

H.248 commands



Protocols & signaling…SIP: Session Initiation Protocol• SIP is a multimedia communication protocol

established by IETF.• It is a text-based application-layer control

protocol independent of lower-layer protocols, designed to establish, modify and terminate two-party or multi-party multimedia sessions over the IP network.



Protocols & signaling…SIP supports proxy, redirect and user location registration functions. It also supports user mobility. it can support and be applied to voice, video and data services. In addition, it can be applied to characteristic services like Presence and Instant Message (similar to MSN).




Requests:• INVITE – initiate call• ACK – confirm final

response• BYE – terminate call• CANCEL – cancel

search/ring

Responses:

• 1xx – Informational

• 2xx – Successful

• 3xx – Redirection

• 4xx – Request Failure

• 5xx – Server Failure

• 6xx – Global Failure

SIP message types




Blue parts are SIGTRAN (Signaling Transport).

IP

SCTP

SUA

M2PA M3UA

MTP3

BSSAP

SCCP

TCAP

MAP

H.248 TUP/ISUP

M2UA

MTP3

SS7 SCCP-User Adaptation Layer SS7 MTP2-User Peer-to-Peer Adaptation Layer

SS7 MTP3-User Adaptation Layer

SS7 MTP2-User Adaptation Layer

IETF SIGTRAN Protocol Model



http://www.openss7.org/sigtran03.html





• SCTP: Stream Control Transmission Protocol

• A reliable connection-oriented transport protocols

• At the same layer as TCP and UDP in network model

• SCTP is designed to transport PSTN signaling messages over IP networks

SCTP Protocol




• An association is an SCTP connection. • The creation of an association is initiated by an

SCTP user. To guarantee the security and prevent malicious attacks, the cookie mechanism is adopted during the starting of an association.

• The connection creation and release is used for the transition of the connection status and abnormality handling.

Association




• M3UA is the adapter layer for SS7 MTP3 user. • Implement the interconnection between SS7

over TDM and IP• M3UA provides powerful routing function

M3UA Protocol



Unit Seven Comparing CDMA to Other

Cellular Technologies

ContentsAdvantages provided by CDMADisadvantages of CDMA


96

High privacy, hard to wiretapping

Spread code

Informationsignal

TX

Demodulatedsignal

RX

Spread code

Spread signalSignal can be sent belowthe noise .

Advantages of CDMA


97

Good voice quality, uses 8k QCELP, 13K QCELP,8k EVRC, voice coding - the best coding method in the world.

Voice quality(MOS) 64k

PCM13kGSM

8k QCELPCDMA

13k QCELPCDMA

8kEVRCCDMA

Advantages…


98

Frequency reuse factor is 1;network design and expanding becomes much easier.

Advantages…

AMPS, D-AMPS, N-AMPS

CDMA

30 30 10 kHz

200 kHz

1250 kHz

1 3 1 Users

8 Users

20 Users1

1

11

11

11

111

111

1 23

4

432

56 17

Typical Frequency Reuse N=7



GSM


99

Call drop rate is very low due to soft handoff

Advantages…

Soft handoff Hard handoff


100

Good Power Control and voice activation make the MS Power low, healthy for body—green mobile phone.

Advantages…

Mean Power Max Power

GSM: 125mW 2W

CDMA: 2mW 200mW


101

Large coverage: Almost 2 times more than GSM.

Example: cover 1000 km2

GSM needs 200 BTS CDMA needs only 50 BTS Attention: exact result need “Link Budget ”

Advantages…


102

High spectrum capacity ， 8--10 times more than AMPS,4—6 times more than GSM

FrequencyTime

Power

FrequencyTime

Power

FrequencyTime

Power

FDMA

TDMA

CDMA

FDMA---Different user use different frequency:TACS,AMPSTDMA---Different user use different time slot of one frequency :GSM 、 DAMPSCDMA---Different user use same frequency at the same time, but with different spreading code

Advantages…


103

Disadvantages of CDMA

Channel pollution (self jamming)Signals from too many cell sites are present

at the subscriber’s phone but none of them happens to be dominant.

the quality of the audio signal degrades leads to customer dissatisfaction and service

loss of the operator.


104

Disadvantages…Lack of international roaming capabilities

compared to GSM, there is the lack of international roaming capabilities.

the ability to upgrade or change to another handset is not easy with this technology.

the network service information for the phone is put in the actual phone unlike GSM which uses SIM card for this.


105

Disadvantages…Near-Far problem

If the nearer transmitter transmits a signal that is orders of magnitude higher than the farther transmitter: then the SNR for the farther transmitter may

be below detect ability farther transmitter may just as well not

transmit.CDMA highly depends on power control

unlike other networks like GSM.College of Telecommunications and

Information Technology106

Documents

CDMApptFinal (2).ppt