Base Station Transmission in UMTS Network Sami Siiki

Base Station Transmission in UMTS Network Sami Siiki Sonera Mobile Networks Finland Supervisor: Prof. Timo Korhonen 3. 6. 2002 1

• • • Background Methodology Problem Results and author’s contribution Conclusions and future work 3. 6. 2002 2

Background • • • GSM transmission based on PDH Timeslot/TRX allocation A more flexible technique needed Release 99: ATM, AAL 2 Co-siting Capacity enlargement 3. 6. 2002 3

Methodology • Mainly literature • Lack of operational networks • Planning process from operator’s point of view 3. 6. 2002 4

Problem • Timeslot allocation in GSM base station transmission • More flexibility is needed: no more fixed bandwidth connections per transceiver unit • ATM and AAL 2: low-bit-rate, delay sensitive, short packets • Demand for fast connection establishment and release (soft handover) 3. 6. 2002 5

Timeslot allocation in GSM 3. 6. 2002 6

ATM traffic in Iub Uu Iub Iu UE UTRAN External Networks CN BTS MSC/VLR RNC BTS Iur GMSC PSTN ISDN HLR BTS Internet RNC SGSN GGSN BTS • PDH or SDH 3. 6. 2002 7

ATM traffic in Iub VC VP Transmission path VP VC • The relation between transmission path, VP and VC 3. 6. 2002 8

ATM traffic in Iub VC switching VCI 1 VCI 2 VCI 3 VPI 1 VCI 4 VPI 2 VCI 4 VPI 3 VCI 1 VCI 2 VPI 4 VPI 5 VCI 2 VP switching • VC and VP switching 3. 6. 2002 9

ATM traffic in Iub, E 1 TS 16: reserved for signaling header 53 octets payload 256 bits/ 125 ms • ATM cells mapped into 2 Mbit/s connection, PCR=4528 cells/s (30 ts used) 3. 6. 2002 10

IMA in Iub Physical link 0 IMA-GROUP PHY Physical link 1 Single ATM cell stream from ATM layer PHY Physical link 2 PHY Single ATM cell stream to ATM layer PHY IMA Virtual Link • Several E 1 s combined to form one larger connection 3. 6. 2002 11

ATM traffic in Iub, STM-1 J 1 B 3 . . . C 2 VC-4 G 1 F 2 H 4 F 3 K 3. . . N 1 VC-4 POH ATM Cell 53 octets • ATM cell mapping into STM-1 VC-4 3. 6. 2002 12

Iub: SDH, PDH and ATM • STM-1 VC-12 3. 6. 2002 13

External ATM network • • • Efficient bandwidth usage Minimize costs Operation and maintenance Addressing Adoption remains to be seen 3. 6. 2002 14

Hub site • Concentration of traffic • Several E 1 s can be combined to form a larger connection • Several larger connections can be combined to for one STM-1 VC-4 • Fault situation 3. 6. 2002 15

Results and author’s contribution • Based on planning process, E 1 s in Iub will be enough for a while => IMA is adopted • STM-1 for every base station is not reasonable at the moment • No general solution exists, depends on operator’s network topology 3. 6. 2002 16

Conclusions and future work • Base station transmission is in turning point • ATM is used now, IP is expected in the future • All-IP concept with different RAN will have an impact on both transmission and base stations • Investments should be moderate and if possible also future proof 3. 6. 2002 17