WCDMA Overview
GSM Vs WCDMA <ul><li>GSM  </li></ul><ul><li>Services : Voice & Data </li></ul><ul><li>Speed : 9.6kbps  (FR, HR, EFR) </li>...
3GPP Releases <ul><li>R99, R4, R5, R6 etc. </li></ul><ul><li>Media gateway introduced in R99. </li></ul><ul><li>IMS introd...
Spreading and Dispreading
Spreading Factor and Data Symbol Rate
Carrier ARFCNDL Downlink Frequency (MHz) Uplink Frequency (MHz) ARFCNUL   10550 2110 1920 9600   10551 2110.2 1920.2 9601 ...
GSM vs WCDMA <ul><li>GSM </li></ul><ul><li>TCH (User payload) </li></ul><ul><li>BCH </li></ul><ul><li>AGCH </li></ul><ul><...
Basic frame structure
Frames Structure <ul><li>DPCCH </li></ul><ul><li>RACH  </li></ul><ul><li>DPDCH & DPCCH </li></ul>
Control Channels vs SF Note : AICH (Acquisition Indicator channel) uses 20 msec as it consist of 2 frames (means 30 slots).
Power Control <ul><li>Open Loop : When UE is IDLE, No air interface link. </li></ul><ul><li>In GSM, RACH is sent with max....
Handover Mechanism <ul><li>Softer Handover: Intra site handover (within two sector of same site. </li></ul><ul><li>Soft Ha...
Rake reciever <ul><li>Deployed in UE to avoid Multipath fading. </li></ul><ul><li>At least 4 rake receiver and 1 search fi...
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Wcdma Overview Presentation

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Wcdma Overview Presentation

  1. 1. WCDMA Overview
  2. 2. GSM Vs WCDMA <ul><li>GSM </li></ul><ul><li>Services : Voice & Data </li></ul><ul><li>Speed : 9.6kbps (FR, HR, EFR) </li></ul><ul><li>Modulation Scheme : GMSK </li></ul><ul><li>Nodes : MSC, BSC, BTS, ME </li></ul><ul><li>Air interfaces : Abis, A, Ater, Gb etc </li></ul><ul><li>BW : 25 MHz with 200 KHz per carrier. </li></ul><ul><li>Channels : BCCH, PCH, SDDCH, FACCH, RACH, etc </li></ul><ul><li>Access Method : TDMA </li></ul><ul><li>Access Media : TDM </li></ul><ul><li>Multipath Fading : Viterbi Equalizer. </li></ul><ul><li>Coding scheme : CS1 (9.6kbps) To CS4 (21.4 kbps) </li></ul><ul><li>BSC to BSC no direct connectivity </li></ul><ul><li>AUC : Triplets (SRES, Ki, RAND) </li></ul><ul><li>WCDMA </li></ul><ul><li>Services : Voice, data, Video </li></ul><ul><li>Speed : 12.8kbps-4.5 kbps (AMR) </li></ul><ul><li>Modulation scheme : QPSK </li></ul><ul><li>Nodes: SMSC, MGW, RNC, RBS, UE </li></ul><ul><li>Air interfaces : Iu-CS, Iu-PS, Uu etc </li></ul><ul><li>BW : 60 MHz, with 5 MHz spread BW. </li></ul><ul><li>Channels: CPICH, PRACH, DPDCH, DPCCH etc </li></ul><ul><li>Access Method : Spread Spectrum technique with wide bandwidth. </li></ul><ul><li>Access Media : ATM, IP, TDM </li></ul><ul><li>Multipath fading : Rake reciever </li></ul><ul><li>Coding Scheme : MCS1(8.8kbps) to MCS9 (59.2kbps) </li></ul><ul><li>RNC to RNC connectivity via MGW. </li></ul><ul><li>AUC : Vector-5 ( XRES, Ik, RAND, Ck, AUTN) </li></ul><ul><li>AUTN : MAC + SQN + Ak + AMF </li></ul>
  3. 3. 3GPP Releases <ul><li>R99, R4, R5, R6 etc. </li></ul><ul><li>Media gateway introduced in R99. </li></ul><ul><li>IMS introduced in R4. </li></ul><ul><li>HSDPA introduced in R5. </li></ul><ul><li>EUL introduced in R6. </li></ul><ul><li>**** : Kindly refer 3GPP for further information. </li></ul>
  4. 4. Spreading and Dispreading
  5. 5. Spreading Factor and Data Symbol Rate
  6. 6. Carrier ARFCNDL Downlink Frequency (MHz) Uplink Frequency (MHz) ARFCNUL   10550 2110 1920 9600   10551 2110.2 1920.2 9601   10552 2110.4 1920.4 9602   10553 2110.6 1920.6 9603   10554 2110.8 1920.8 9604   10555 2111 1921 9605   10556 2111.2 1921.2 9606   10557 2111.4 1921.4 9607   10558 2111.6 1921.6 9608   10559 2111.8 1921.8 9609   10560 2112 1922 9610   10561 2112.2 1922.2 9611 1 10562 2112.4 1922.4 9612   10563 2112.6 1922.6 9613   10564 2112.8 1922.8 9614   10565 2113 1923 9615   10566 2113.2 1923.2 9616   10567 2113.4 1923.4 9617   10568 2113.6 1923.6 9618   10569 2113.8 1923.8 9619   10570 2114 1924 9620   10571 2114.2 1924.2 9621   10572 2114.4 1924.4 9622   10573 2114.6 1924.6 9623   10574 2114.8 1924.8 9624
  7. 7. GSM vs WCDMA <ul><li>GSM </li></ul><ul><li>TCH (User payload) </li></ul><ul><li>BCH </li></ul><ul><li>AGCH </li></ul><ul><li>WCDMA </li></ul><ul><li>DCH : DPDCH (user + L3) & DPCCH (L1 ie Pilot bits, power control). </li></ul><ul><li>PCCPH (Broadcast Info) </li></ul><ul><li>SCPCCH ( FACH + PCH) </li></ul>CPICH, PCCPCH are continuous. S-CCPCH, PICH, AICH, DDCCH, DPCCH are on demands.
  8. 8. Basic frame structure
  9. 9. Frames Structure <ul><li>DPCCH </li></ul><ul><li>RACH </li></ul><ul><li>DPDCH & DPCCH </li></ul>
  10. 10. Control Channels vs SF Note : AICH (Acquisition Indicator channel) uses 20 msec as it consist of 2 frames (means 30 slots).
  11. 11. Power Control <ul><li>Open Loop : When UE is IDLE, No air interface link. </li></ul><ul><li>In GSM, RACH is sent with max. power. </li></ul><ul><li>In WCDMA, RACH is sent with min. power. </li></ul><ul><li>Inner Loop (fast power control): When UE connected. </li></ul><ul><li>SIR) target< SIR)estimat-----Reduce Power </li></ul><ul><li>SIR) target> SIR)estimat-----Increase Power </li></ul><ul><li>Frequency of commanding for power control: </li></ul><ul><li>GSM : 2 times/sec ; CDMA : 800 times/sec ; WCDMA : 1500 times/sec. </li></ul><ul><li>Outer loop (Slow power control) : RNC to control BLER. </li></ul><ul><li>BLER high------Quality low-----SIR) target increase. </li></ul><ul><li>BLER low------Quality high-----SIR) target reduce. </li></ul>
  12. 12. Handover Mechanism <ul><li>Softer Handover: Intra site handover (within two sector of same site. </li></ul><ul><li>Soft Hanover: Handover between two sites. </li></ul><ul><li>Hard Handover: </li></ul><ul><li>Inter frequency (IF): WCDMA f1 and WCDMA f2. </li></ul><ul><li>Inter Radio Access technology (IRAT): WCDMA to GSM. </li></ul>
  13. 13. Rake reciever <ul><li>Deployed in UE to avoid Multipath fading. </li></ul><ul><li>At least 4 rake receiver and 1 search finger is deployed. </li></ul><ul><li>Inner loop power control is used to overcome the fast fading. </li></ul><ul><li>Maximum ratio Combiner (MRC) is employed as combining technique. </li></ul><ul><li>Search Finger is used when performing handovers, scans neighbor node B and estimated the channel parameters. </li></ul>
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