Presentation / Author / Date 1 Nokia Siemens Networks
Network planning & optimisation Technical sharing session Jonathan Tam Network planning & optimisation expert 4 Nov 2009 Soc Classification level Presentation / Author / Date 2 Nokia Siemens Networks Agenda 1. Antenna separation recommendation 2. 2G-3G interworking 3. HSPA implementation strategy 4. Capacity management 5. Inbuilding coverage 6. Any other topics Soc Classification level Presentation / Author / Date 3 Nokia Siemens Networks 1. Antenna separation recommendation 2. 2G-3G interworking 3. HSPA implementation strategy 4. Capacity management 5. Inbuilding coverage 6. Any other topics Soc Classification level Presentation / Author / Date 4 Nokia Siemens Networks Antenna separation recommendation Horizontal spacing is the distance between antenna centre lines Vertical spacing is the gap between antennas Soc Classification level Presentation / Author / Date 5 Nokia Siemens Networks Antenna separation recommendation RF Filters to allow even closer separation of antennas may be Considered. The antenna separation is typically greater than 0.5m and provided the relative angle is greater than 90Deg a filter is not required. With angles less than 90Deg and panel separation less than 0.5m, a 900MHz GSM bandpass filter may be required in the GSM base station antenna feeders for each polarisation Soc Classification level Presentation / Author / Date 6 Nokia Siemens Networks Antenna separation recommendation For the instance of a dual band GSM panel mounted in close proximity to a 3G antenna, and the GSM dual band antenna is a 2 port type with BTS combining within the equipment shelter, it is not necessary to install a 900MHz band pass filter. The 1800MHz band pass filter is still required. This is because the 900/1800 dual band combiner has sufficient isolation performance for 900MHz. Soc Classification level Presentation / Author / Date 7 Nokia Siemens Networks 1. Antenna separation recommendation 2. 2G-3G interworking 3. HSPA implementation strategy 4. Capacity management 5. Inbuilding coverage 6. Any other topics Soc Classification level Presentation / Author / Date 8 Nokia Siemens Networks 2G-3G interworking Main objectives: 1. 3G capable UEs should camp on 3G as long as radio conditions allow. 2G network is only used by 3G capable UEs when 3G coverage becomes weaker. 2. Consistent 2G-3G interworking in Idle & Connected mode to allow smooth intersystem reselection or handover for 3G capable UEs In idle mode Ping pong degrades not only customer experience but also increases signalling load due to location update unnecessarily. A safe margin for 2G-3G interworking should be made available to stop ping pong In connected mode Handover should be executed without causing additional drop calls Coverage related ISHO thresholds can be made differently for voice and PS calls ISHO threshold should be set in line with idle mode parameters Load balancing Load & service based HO can be used to offload 3G traffic onto 2G Soc Classification level Presentation / Author / Date 9 Nokia Siemens Networks 2G-3G interworking 3G parameters Sintrasearch, Sintersearch and SsearchRAT are compared with Squal (CPICH Ec/No -Qqualmin) in S-criteria for cell re-selection Soc Classification level Presentation / Author / Date 10 Nokia Siemens Networks 2G-3G interworking >-8 -8..-10 -10..-14 <-14 Soc Classification level Presentation / Author / Date 11 Nokia Siemens Networks 2G-3G interworking 2G parameters Qsearch_I, Qsearch_P, FDD_Qmin and FDD_Qoffset are used for 2G>3G cell reselection Soc Classification level Presentation / Author / Date 12 Nokia Siemens Networks 2G-3G interworking In connected mode, FMCS & FMCG parameters are used to trigger ISHO due to DL DPCH power, UL Qual, UE Tx power, CPICH RSCP & CPICH EcNo. Different sets of FMCS can be FMCG can be applied to RT, NRT and HSDPA services. Soc Classification level Presentation / Author / Date 13 Nokia Siemens Networks 2G-3G interworking Lessons learnt from other networks: 1. Poor 3G>2G ISHO success rate Mainly due to high congestion on 2G TCH Mismatch or missing datafill in MSS or SGSN Solutions: 2G TRS expansion, 2G load balancing, Half rate, consistency check 2. UEs camp on 2G even though well in 3G coverage area Missing neighbours Incorrect 2G Idle mode parameter Solutions: Neighbour size audit, 2G parameter consistency check 3. 3G PS data calls switch to 2G GPRS or EDGE very frequently Too conservative ISHO thresholds for PS service Solutions: Fine-tune ISHO thresholds, disable HSDPA ISHO Soc Classification level Presentation / Author / Date 14 Nokia Siemens Networks 1. Antenna separation recommendation 2. 2G-3G interworking 3. HSPA implementation strategy 4. Capacity management 5. Inbuilding coverage 6. Any other topics Soc Classification level Presentation / Author / Date 15 Nokia Siemens Networks HSPA implementation HSPA implementation A number of HSPA upgrade steps available to meet different levels of mobile broadband requirement Step Description Max Mbps per user BTS throughput Mbps Simult HSDPA users 3 (2010 target) Second carrier deployment in RU20 21.1 21.1 - 63.3 72 - 216 Layering features Depending Depending on scheduler on scheduler 2 (2009 target) Second carrier deployment in RU10 14.4 14.4 - 43.2 64 - 192 Layering features Depending Depending Node B capacity expansion on scheduler on scheduler 1 (Intermediate) 15 channel codes 10.8 10.8 - 32.4 48 - 144 Shared or dedicated scheduler Now 5-10 channel codes 3.6 - 7.2 10.8 48 Shared scheduler 1 2 3 4 Soc Classification level Presentation / Author / Date 16 Nokia Siemens Networks HSPA implementation When to upgrade from 1+1+1 to 2+2+2 second carrier? for higher HSDPA throughput (dedicated HSPA carrier) More available HSDPA codes from dedicated second carrier for HSDPA More cleaner frequency & better CQI for improved voice performance (dedicated HSPA carrier) HSDPA move to second carrier. DL interference becomes lesser for voice services for extremely high demand of HSPA traffic (shared HSPA/R99 carrier) Both layers to be HSPA enabled to provide maximum HSPA traffic Soc Classification level Presentation / Author / Date 17 Nokia Siemens Networks HSPA implementation When to upgrade from 1+1+1 to 2+2+2 second carrier? When HSDPA code availability becomes smaller Soc Classification level Presentation / Author / Date 18 Nokia Siemens Networks Dedicated HSPA layer for 2+2+2 HSPA implementation High HSDPA/HSUPA throughput due to clean frequency DRRC F1->F2 (HSPA capable terminals) is done to clean frequency, Idle mode users directed/kept always on F1 and F2 cell_FACH, cell_PCH users stay on F2, typically all HSPA terminals stay in cell_PCH instead in idle mode so those can be kept in F2 Continuous R99 layer with SHOs (supports high speed mobility for voice) Voice call performance on F1 improves due to all HSPA traffic moved to F2 -> less interference When HSDPA/HSPA supporting terminal penetration increases the HSPA layer supports more and more traffic without interfering R99 layer F2: HSPA F1:R99 GSM F2: HSPA F1:R99 GSM Soc Classification level Presentation / Author / Date 19 Nokia Siemens Networks Shared HSPA/R99 carrier for 2+2+2 HSPA implementation Extremely high HSPA capacity as HSPA on both layers Both layers support HSPA and R99 so only #HSPA users need to be balanced (F2 higher HSPA usage layer => F1 primarily for voice and R99 users) Stable HSPA throughput for mobile wireless broadband user F2: HSPA + R99 F1: HSPA + R99 GSM Soc Classification level Presentation / Author / Date 20 Nokia Siemens Networks Key optimisaiton achievements NSN Sumatra optimisation taskforce delivered the following key achievements Significant improvement in HSDPA accessibility Significant improvement in AMR & PS DCR A reduction of 1918 CEs used during peak hours for the whole NSN Sumatra area a decrease of 12.5% of total 15498 CEs used after optimisation. At the same time, 3G AMR traffic has increased by 200% for Batam while 3G voice & data traffic remains steady for other cities. Soc Classification level Presentation / Author / Date 21 Nokia Siemens Networks Key optimisaiton achievements NSN Sumatra optimisation taskforce was setup in June 2009 Dedicated optimisation team for Batam, Medan & Palembang Key optimisation activites were carried out as follows Soc Classification level Presentation / Author / Date 22 Nokia Siemens Networks 1. Antenna separation recommendation 2. 2G-3G interworking 3. HSPA implementation strategy 4. Capacity management 5. Inbuilding coverage 6. Any other topics Soc Classification level Presentation / Author / Date 23 Nokia Siemens Networks Capacity management After HSDPA launch and active marketing HSDPA data volume grew 5 times in just 2 weeks from 2500Gb to 12500Gb and doubled during next 3 and half months (ten times growth in 4 months) Reasons for data growth 1. High data rates 2. Flat rate pricing 3. Simple installation 4. Laptops penetration 13 TB/day 10 TB/day Mobile broadband traffic grows exponentially Soc Classification level Presentation / Author / Date 24 Nokia Siemens Networks Capacity management Proactive capacity monitoring is important to identify potential bottlenecks especially in RAN. Soc Classification level Presentation / Author / Date 25 Nokia Siemens Networks Capacity management No >48 simultaneous users exceeded Possibility to reduce the usage? Yes Yes More throughput needed No No Iub capacity for HSDPA supports higher throughput Yes Possibility to reduce the R99 usage? No Yes No Upgrade the Iub #available SF 16 codes supports new scheduler Yes Possibility to reduce the R99 usage? No No Yes Upgrad e to 2 nd carrier BTS CE capacity supports addition of schedulers Add more schedulers Yes Possibility to reduce the R99 usage? No No Upgrade the BTS Throughput limited by BTS power, CQI or user location? Upgrade the BTS power Possibility to optimise the throughput Yes No Yes Soc Classification level Presentation / Author / Date 26 Nokia Siemens Networks Capacity management Upgrade 2+2+2 to maximise data usage through the monitoring of : HSDPA code availability Simultaneous HSDPA users Capacity upgrade for other NE or interface through the monitoring of: CE usage Iub reservation & utilisation ATM CID usage IuPS load RNC/DMPG load etc Soc Classification level Presentation / Author / Date 27 Nokia Siemens Networks Capacity management: Iub Below is comparison of RNC CAC reservation (per BTS per hour) relation to actual usage for the case (hours & BTSs) of no HSDPA usage As it can be seen the reserved capacity by the RNC CAC is not fully utilised by the R99 connections, from simple trend lining the utilisation is roughly In DL 1/3 from CAC reservation (but increasing trend of utilisation is visible when the reservation increases) In UL 1/4 from DL CAC reservation (but increasing trend of utilisation is visible when the reservation increases) Also the trend depends on traffic profile (share of traffic between CS and PS) -10% -5% 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50% 0% 10% 20% 30% 40% 50% 60% 70% 80% RNC CAC Reservation % U t i l i s a t i o n
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% Soc Classification level Presentation / Author / Date 28 Nokia Siemens Networks Capacity management: CID Each AAL2 connection requires individual CID CCCH CCCHs consists of FACH-u, FACH-c, PCH & RACH i.e. per cell 4 CIDs are needed 3 sector site requires therefore 3*4=12 CIDs for CCCH Normal call requires 2 CIDs: SRB RB HSPA Call requires 3 CIDs: SRB MAC-d Flow in DL UL Return Channel (HSUPA or R99) Multi-RAB Call requires one additional CID per additional RAB One VCC can have 248 CIDs and lack of CIDs can cause call setup to fail due to TRANSMISSION Soc Classification level Presentation / Author / Date 29 Nokia Siemens Networks 1. Antenna separation recommendation 2. 2G-3G interworking 3. HSPA implementation strategy 4. Capacity management 5. Inbuilding coverage 6. Any other topics Soc Classification level Presentation / Author / Date 30 Nokia Siemens Networks Inbuilding coverage 3G inbuilding coverage is best served by dedicated inbuilding solution for high rise building 3G interference caused by reflections and defractions from building when directional antenna transmitted from adjacent building. Providing dominant coverage is the most important principle in 3G coverage planning Utilising existing 2G DAS system and co-locate if possible