GSM P&O Training Material for Special Subject-2-3G Interworking V1.0

Views:
 
Category: Education
     
 

Presentation Description

ZTE Docs

Comments

Presentation Transcript

2G-3G Interworking:

2G-3G Interworking Suitable for Staff with P&O Skill Certificate III or Lower Issued by GSM Network P&O Dept GSM P&O Training Materials for Special Subjects

Version introduction:

Version introduction Version Date Writer Assessor Translator Amendment Records V1.0 2009-03-01 Guo Hongchang Zheng Hao Lu Yan No

Purpose of the course:

Purpose of the course To know 2G-3G interworking principles To know similarities and differences of 2G-3G interworking solutions To know the issue of the interference between 2G-3G

PowerPoint Presentation:

2G-3G interworking targets 2G-3G interworking principles 2G-3G interworking solutions 2G-3G interworking implementation solutions suggested 2G-3G subscribers’ demand and technology support 2G-3G co-location and interference issues

2G-3G interworking targets:

5 2G-3G interworking targets To guarantee the continuity of 3G service by making full use of the present network investment To solve the capacity problems in areas where 2G radio resources are already very limited To achieve the communications of 2G and 3G network with minimum costs of network upgrade Targets come from classification and organization of subscriber requirements. E.g., 2G/3G complementary coverage to guarantee the continuity of 2G/3G Solve 2G capacity problems in areas where 2G radio resources are limited Try one’s best not to change the using habits of subscribers: no change of phone number, no change of card, and so on Operate together with 2G network including 2G network upgrade and evolution Use same/different 3G PLMN number Prevent unauthorized subscribers from being connected to 3G network Minimize 2G/3G networking impact on 2G network Issues about equipment compatibility of 2/3G networking and about charging ……

2G-3G interworking targets at different stages:

6 2G-3G interworking targets at different stages With the improvement of network construction, 2G-3G interworking targets also change: evolution at different stages Keep the continuity of 2G-3G service Avoid impact on 2G network stability Initial stage of construction 2G-3G network load balance 2G-3G network will manage the operation together Mature stage of network 2 G 3 G

Initial planning of network—by 2/3G resources, develop 3G subscribers rapidly:

7 Initial planning of network—by 2/3G resources, develop 3G subscribers rapidly Areas of high value Important areas 3G/HSDPA : Voice/visual/medium or high rate data service Suburbs and countryside GSM/GPRS : Voice/low rate data services Capacity: Coverage: Full coverage Continuous coverage for important areas Certain Capacity pressures Idle, subscribers to be developed Initial strategy of coexistence of two networks: 3G forms complete coverage on basis of GSM; GSM reduces expansion pressures through 3G; With advantages of 3G, develop 3G subscribers rapidly GSM 3G 2G/3G develop together One Radio Network

Middle planning of network—improve 3G coverage, make full use of resources released by 2G:

8 Middle planning of network—improve 3G coverage, make full use of resources released by 2G Important areas 3G/HSDPA : Voice/visual/medium or high rate data service Suburbs and countryside GSM/GPRS : Voice/low rate data service Capacity: Coverage: Full coverage Basically continuous coverage, and development towards the countryside Become idle gradually Rapid development, and pressures of urban areas 3G coverage is gradually improved, and countryside subscribers should be developed quickly. The number of 2G subscribers is reduced, and the network becomes idle gradually, so value areas can consider to use released DCS 1800M resources to develop LTE. 64QAM will be introduced to urban HSDPA network, and software upgrade HSPA+ will be realized, and the competitive power of data service will be enhanced. Planning of trial service in LTE value areas will be speeded up to experience super high rate data service. GSM 3G Areas of high value LTE trial service Trial service in value areas Trial service of super high rate data service LTE Network strategy 64QAM is introduced to some 3G areas to realize HSPA+

PowerPoint Presentation:

2G-3G interworking targets 2G-3G interworking principles 2G-3G interworking solutions 2G-3G interworking implementation solutions suggested 2G-3G subscribers’ demand and technology support 2G-3G co-location and interference issues

2G-3G interworking principles:

10 2G-3G interworking principles Principles: Manage to use 2G network to expand 3G coverage, and keep the continuity of service for 3G subscribers; Manage to reduce handover times between systems; Manage to provide 3G subscribers with 3G network service; Manage to avoid upgrade of present 2G/2.5G network; Observe the principle of giving priority to subscribers’ experience. Node B BTS BTS 3/2G 2G Dual mode Dual mode

Suggestions for the realization of 2G-3G interworking:

11 Suggestions for the realization of 2G-3G interworking Manage to form continuous signal coverage within 3G coverage areas Reduce the zones which have no signals or weak signals, and especially avoid these zones in areas where there is a high pedestrian flow. In these areas, 3G signals usually fade suddenly, and have no time to do measurement or handover between systems, so the failure probability of handover between systems might be quite high. Manage to choose areas where there is a low pedestrian flow as 3G network edge Avoid the choice of edge in areas where there is a high pedestrian flow, like stations, docks and so on, so as to reduce the possibility of intersystem handover. In addition, this can also avoid signaling interaction delay/failure, and the following handover call drop, which result from inefficient processing ability. Choose well covered GSM areas as 3G edge This is good for successful handover from 3G to GSM. In other words, there should be no overlapping areas between GSM edge and 3G edge. This can reduce the possibility of intersystem measurement failure, signaling interaction failure and the following call drop, which are caused by the problem of GSM network signal strength.

PowerPoint Presentation:

2G-3G interworking targets 2G-3G interworking principles 2G-3G interworking solutions 2G-3G interworking implementation solutions suggested 2G-3G subscribers’ demand and technology support 2G-3G co-location and interference issues

2G-3G interworking solutions:

13 2G-3G interworking solutions Overview 2G network protocol doesn’t consider 2G-3G interworking until R99 edition, while 3G protocol starts to consider the issue of 2G-3G interworking from its initial formulation. Main network element related to the realization of 2G/3G interworking 3G MSC/VLR, 3G SGSN, 3G HLR network element ; Dual mode mobile phone Main implementation solutions of 2G-3G interworking Solution of no upgrade of 2G network equipment; Solution of a small number of upgrades of 2G network equipment; Solution of a large number of upgrades of 2G network equipment; (not recommended)

2G-3G interworking solutions:

14 2G-3G interworking solutions Basic functions realized by 2G-3G interworking Choice of PLMN; Cell reselection; Handover Main network element related to the realization of 2G/3G interworking 3G MSC/VLR, 3G SGSN, 3G HLR network element; Dual mode mobile phone Solutions to realize 2G-3G interworking All the interworking solutions consist of 3 interworking functions (choice of PLMN, cell reselection, and handover). Each solution corresponds to a different 2G network upgrade scale.

2G-3G interworking solution: No upgrade of 2G network equipment:

15 2G-3G interworking solution: No upgrade of 2G network equipment The solution is realized through “The Selection of PLMN” 2G and 3G network are assigned a different PLMN number. The connection to 3G is realized by the reselection function of dual mode terminal HPLMN (home PLMN), and not by 2G equipment upgrade; The premise is that HPLMN in SIM card or USIM card is 3G PLMN. So 3G 2G one-way handover and cell reselection can be realized.

2G-3G interworking solution: No upgrade of 2G network equipment:

16 UE RNC 3G CN BSC 2G CN 6 minutes Some dual mode terminals firstly choose GSM network to register. Every six minutes, dual mode terminals, which use a new card, will try 3G network which performs as a home network. Problem: within the same coverage area, some dual mode terminals will firstly stay in GSM network, and can not use 3G service. Theory of PLMN solution: 3G subscribers all use a newly made USIM card, 3G network uses a new network number, and the length of time for making a USIM card belongs to network choice information. So all 3G subscribers who use a new USIM card will firstly stay in 3G network. 2G-3G interworking solution: No upgrade of 2G network equipment

2G-3G interworking solution: No upgrade of 2G network equipment:

17 3G GSM 3G - >GSM : It is realized by cell reselection, and voice handover and PS handover will be configured. GSM - >3G : In idle state, reconnection to 3G is realized by HPLMN reselection. Voice handover is not configured, and PS handover is not supported. 3G network must be constructed with a network number different from GSM network. For 3G subscribers, 3G network will be configured as HPLMN. Advantages There is no need of the functions of GSM present network to upgrade software. There are fewer cooperating tests of GSM and 3G. Disadvantages If GSM subscribers become 3G subscribers, SIM card must be changed. HPLMN reselection needs 6 minutes, so subscribers may be less dissatisfied. Requirements of the solution Choice of PLMN solution is suitable for those mobile telecommunications carriers who can’t realize GSM to 3G cell reselection. 2G-3G interworking solution: No upgrade of 2G network equipment

2G-3G interworking solution: Small scale upgrade of 2G network equipment:

18 2G-3G interworking solution: Small scale upgrade of 2G network equipment The result of this solution is that “priority is given to connection to 3G network, and one-way voice handover between 2G/3G network is realized”. Service handover between 2G/3G systems is rapidly realized by cell reselection and handover. Voice handover, data service handover, and cell reselection function from 3G to 2G are all realized. 2G to 3G data service handover and cell reselection function are both realized.

2G-3G interworking solution: Small scale upgrade of 2G network equipment:

19 UE RNC 3G CN BSC 2G CN Some terminals firstly choose GSM network to register. Configuration of broadcast message parameter makes it easy for dual mode terminals to realize 2G-3G reselection. Some seconds System broadcast message Parameters configuration delivered by RNC makes terminals to stay in 3G network if possible. Problem: within the same coverage area, some dual mode terminals will firstly stay in GSM network, and can not use 3G service. Theory of cell reselection solution: 2G BSC delivers broadcast message to require dual mode terminals to be reconnected to 3G by intersystem cell reselection. 2G-3G interworking solution: Small scale upgrade of 2G network equipment

2G-3G interworking solution: Small scale upgrade of 2G network equipment:

20 3G GSM 3G - >GSM : It is realized by cell reselection, and voice handover and PS handover will be configured. GSM - >3G : In idle state, reconnection to 3G is realized by cell reselection. Voice handover is not configured and PS handover is configured. Both same network numbers or different network numbers are accepted. Construction of the same network numbers is recommended. GSM network is required to support 2G ->3G cell reselection function. Requirements of the solution Advantages Subscribers don’t need to change SIM card and phone number. Rapid return from 2G to 3G makes subscribers feel satisfied. Disadvantages Upgrading GSM network is required to support 2G->3G cell reselection. Debugging of present network involves a lot of work. The cell reselection solution is a 2G-3G interworking solution which is preferred by world mainstream mobile telecommunications carriers at present in this industry. 2G-3G interworking solution: Small scale upgrade of 2G network equipment

2G-3G interworking solution: Large scale of upgrade of 2G network equipment (not recommended):

21 2G-3G interworking solution: Large scale of upgrade of 2G network equipment (not recommended) The result of this solution is that “priority is given to connection to 3G network, and 2G/3G networking realizes one-way speech handover”. Service handover between 2G/3G systems is rapidly realized by cell reselection and handover. Voice handover, data service handover, and cell reselection function from 3G to 2G are all realized. 2G to 3G data service handover and cell reselection function are both realized.

2G-3G interworking solutions: Comparison of these three solutions:

22 2G-3G interworking solutions: Comparison of these three solutions Comparison of functions and upgrade requirements First solution: Choice of PLMN Second solution: One-way speech handover Third solution: Two-way handover Functions 3G  2G voice handover: √ 3G 2G PS handover: √ 3G 2G cell reselection: √ 2G 3G voice handover: × 2G 3G cell reselection: × 2G 3G PS handover: × 3G  2G voice handover: √ 3G 2G PS handover: √ 3G 2G cell reselection: √ 2G 3G voice handover: × 2G 3G cell reselection: √ 2G 3G PS handover: √ 3G  2G voice handover: √ 3G 2G PS handover: √ 3G 2G cell reselection: √ 2G 3G voice handover: √ 2G 3G cell reselection: √ 2G 3G PS handover :√ Similarities Upgrade 2G HLR or construct a new 3G HLR based on the number portability feature supported by the network 2G MSS/BSS equipment modifying requirements No modification BSS modifies system message SI2ter to add WCDMA adjacent cell information; add system message SI2quater (optional); modify system message SI3 If PLMN in system broadcast message is different, 2G MSC location upgrade response message and the like need to be upgrade to R99 protocol edition. Modifications of the second solution + upgrade to support measurement control for handover between systems handover judgment, and handover signaling procedure. BSS and MSC of 2G system both need to be modified. Requirement for the original subscribers The card must be changed. None None Handover Speed Between systems 3G  2G is realized by cell reselection, and is quick; 2G 3G is realized by the choice of HPLMN, and is slow. 3G  2G two-way handover is realized by cell reselection, and is quick. The same as the second solution

2G-3G interworking solution: Analyses of risk costs:

23 2G-3G interworking solution: Analyses of risk costs Comparative analyses of risk costs First solution: Choice of PLMN Second solution: One-way speech handover Third solution: Two-way handover Networking risks No risks BSC needs to do a small number of software upgrades, and there is some risk. A large number of upgrades of both BSS and MSC, and there is a high upgrade risk. Networking costs 3G network construction costs First solution + 2G network software upgrade costs 1 (system message) The second solution + 2G network software upgrade costs 2 (judgment process of intersystem handover) Operation and maintenance costs 3G network operation and maintenance costs 3G network operation and maintenance costs + 2G network operation and maintenance costs 3G network operation and maintenance costs + 2G network operation and maintenance costs Subscriber costs The card must be changed/or the mobile phone has preferred access function. No requirements No requirements

2G-3G interworking solution: Construction solutions at different stages:

24 2G-3G interworking solution: Construction solutions at different stages In consideration of the interworking features described above, construction solutions at different stages are recommended. Network status Interworking solutions recommended Remarks First stage At the initial construction stage, present network equipment upgrade requirements can’t be satisfied. So in a short term, requirements for 2G  3G cell reselection can’t be satisfied. First solution Subscribers use a new SIM card to realize preferred access to 3G by HPLMN reselection. Second stage 2G equipment upgrade conditions are mature Second solution From 2G/3G interworking to the same PLMN network number

PowerPoint Presentation:

2G-3G interworking targets 2G-3G interworking principles 2G-3G interworking solutions 2G-3G interworking implementation solutions suggested 2G-3G subscribers’ demand and technology support 2G-3G co-location and interference issues

2G-3G interworking implementation solutions suggested: Main points:

26 HLR construction solution: Cell configuration strategy Local area network networking strategy Signaling network sharing, long distance tandem switch Network element sharing Influence over performance and functions caused by the combination of PLMN and LAI 2G-3G interworking implementation solutions suggested: Main points

2G-3G interworking implementation solutions suggested: HLR construction solution:

27 2G/3G use the same network number: 2G and 3G HLR entity are integrated. 2G HLR has the function to support 3G subscribers to create an account. 2G HLR needs to be upgraded to support contracting service for 3G subscribers. (recommended) 2G and 3G each has an independent HLR entity. They use different IMSI, MSISDN section number to distinguish 2G HLR and 3G HLR. HLR doesn’t need to be upgraded. However, its obvious disadvantage is that original 2G subscribers must use a new MSISDN number, if they want to use 3G service. 2G/3G network use different network numbers: 2G and 3G HLR entity are integrated. 2G HLR has the function to support 3G subscribers to establish a new account. 2G HLR needs to be upgraded to support contracting service for 3G subscribers, and telephone number function of different network numbers. 2G and 3G HLR entity are independent. Number portability service is used to keep MSISND of subscribers so as to provide the subscribers with the greatest convenience. 2G HLR doesn’t need to be upgraded. By number portability, the original 2G subscribers can change SIM card. In this way, the subscribers can not only firstly use 3G service but also make full use of the advantage of number portability, that is, MSISDN number is reserved for subscribers. (recommended) 2G-3G interworking implementation solutions suggested: HLR construction solution

2G-3G interworking implementation solutions recommended: Cell configuration strategy:

28 Strategy recommended: Within 3G coverage areas, 3G  2G interworking is not supported, but the edge of 3 coverage areas support handover towards 2G, and cell reselection. Disadvantages of 3G->2G handover supported by the whole network: High probability of call drop will exist, because success rate of intersystem handover is much lower than that of intra-system handover. It is hard to control the target coverage area which is selected during cell reselection and handover, because of the ping-pong effect. If the compact model is used, it can increase downlink emission power of the base station and the mobile phone, increase interference, and reduce capacity. Network configuration and maintenance is complicated. The initial optimization and manual configuration involves much work, and signaling costs a lot. 2G-3G interworking implementation solutions recommended: Cell configuration strategy

2G-3G interworking implementation solutions suggested: Local area network:

29 Hybrid networking Create dual mode MSC/SGSN or upgrade the original 2G MSC/SGSN to 2G/3G dual mode MSC/SGSN. Independent networking Create 3G MSC/SGSN, and keep the original 2G MSC/SGSN; local traffic between 3G network and 2G network is connected by GMSC of 2G. Independent networking can support independent service of the two networks. They won’t influence each other, but they can integrate with each during their development. 2G-3G interworking implementation solutions suggested: Local area network

2G-3G interworking implementation solutions suggested: Make use of network sharing function:

30 Signaling network sharing, and long distance tandem exchange Local switch terminates BICC signaling (by SIGTRAN) and IP bear traffic, traditional TDM interface is provided outside. Network element sharing Equipment sharing GMSC/SCP/GGSN/SC 2G-3G interworking implementation solutions suggested: Make use of network sharing function

2G-3G interworking implementation solutions suggested: Network element and requirements for equipment version:

31 31 2G-3G interworking implementation solutions suggested: Network element and requirements for equipment version Functions Network element Version requirements Special needs 2G 3G cell reselection BSC R99 3GPP TS 05.08 3GPP TS 04.18 ARD control access CN R6 3GPP TS 29.002 Compatible with original 2G equipment 3G MSC MAP : Compatible with MAP-Prep-Handover req of MAP Phase 2 3G MSC Compatible with original BSC equipment, and capable of circumventing influence from SAI 3G MSC Forced to add Cipher information Video phone fall back 3G CN R6 MAP : Alternative Channel Type UE R6 Support CS64 decline to AMR processing RNC R6 Alternative RAB Parameters

2G-3G interworking implementation solutions suggested: Influences over PLMN and LAI:

32 32 2G-3G interworking implementation solutions suggested: Influences over PLMN and LAI 3G GSM Cell reselection solution Different PLMN solution 2G/3G interworking Same PLMN, different LAI Different PLMN IMSI (SIM card) No change Change the card Choice of network Connected to the network by cell reselection Choose the network by cell reselection and HPLMN Access control HLR controls whether 2G subscribers will be allowed to be connected to 3G network. MSC/VLR/SGSN can control whether subscribers will be connected to 3G network. The mainstream mobile telecommunications carriers will prefer the reselection solution - e.g., adopt the solution of using different network numbers of Hutch Suggestion: Upgrade the present GSM equipment according to the requirements of the target network so as to guarantee the satisfactory experience of future 3G subscribers!

PowerPoint Presentation:

2G-3G interworking targets 2G-3G interworking principles 2G-3G interworking solutions 2G-3G interworking implementation solutions suggested 2G-3G subscribers’ demand and technology support 2G-3G co-location and interference issues

Requirements analysis of user policy and technology support:

34 34 Requirements analysis of user policy and technology support Reduced costs of switch to other networks Subscribers can use 3G service without the change of card or number. Controllable subscribers’ switch to other networks Some areas have the demand for controlling subscribers’ switch to other networks Convenient and rapid switch to other networks Both telephones and business halls will be ready for 3G service. Business marketing 2/3G use the same network number. Adopt cell reselection solution. ARD Control subscribers’ access connection to 3G Initial demand from carriers Analyses of demand Technology support IMSI section number segment number controls subscribers’ connection to 3G. Make use of advantages of 3G and adopt positive marketing strategies Obvious costs advantages of 3G voice and data service

User policy—ARD-based access control of 2/3G subscribers :

35 35 User policy—ARD-based access control of 2/3G subscribers Upgrade 2G and 3G HLR, add an information ID field: Subscriber data extension in HLR is used to add control information ID field (ARD: Access Restriction Data) to show subscriber access attribute. 2G and 3G subscriber access control is realized by ARD. During location upgrade, the ADR information is transmitted to MSC Server/VLR by extended “Insert Subscriber Data” signaling. Core network equipment MSC Server/VLR distinguishes the radio networks which subscribers are connected to: VLR distinguishes the radio network property used by a subscriber, that is, whether the subscriber logs in from BSS or UTRAN. According to the radio network attribute used by a subscriber, and ARD value delivered in ISD operation, VLR defines the relationship between the subscriber property and access network property, and corresponding application scenarios. This is shown in the following table: Access result Meaning of ARD field ARD value Application scenarios UTRAN system access denied UTRAN Not Allowed 01 Control whether to be connected to 3G network GREAN system access denied GREAN Not Allowed 10 Constraints: Both HLR and VLR need to support ARD function. ARD User Data 01: UTEAN not allowed 10: GREAN not allowed

Business policy of analyzing demand and technology support :

36 36 Business policy of analyzing demand and technology support Attach importance to subscriber experience Make use of 3G service advantages, and make full use of 3G service Fewer parameter configurations No ping-pong handover Improve service QoS 2/3G service continuity Convenient deployment / maintenance 3G selective preference strategy Reliable 2/3G handover Cell reselection 2G BSC is only configured with 3G frequency points One-way handover Cell parameter control Initial demand from carriers Analyses of demand Technology support

Service strategy–3G selective preference in cell reselection, improvement of service QoS:

37 37 Service strategy–3G selective preference in cell reselection, improvement of service QoS Criterion for UE starts measurement of UTRAN : Qsearch_I <=7 && RLA_C< R(Qsearch_I) If Qsearch_I =7 , R(Qsearch_I) = +  3G priority Unconditional measurement of 3G signal Voice service If average GSM MOS value is 3.45, and average 3G MOS value reaches 4.2, user experience is high . Data service 3G provides special service like video phone, and video streaming media and so on, which can’t be provided by 2G. Download rate of HSDPA is 13 times higher than that of GPRS and 7 times higher than that of EDGE. So internet surfing is more smooth. * Hong Kong 3G network values measured in practice Test scenario MOS value (Sampling of more than one hundred times of calling) Intra-NodeB calling* 4.245 Inter-NodeB calling (not pass Iur)* 4.284 Inter-NodeB calling (pass Iur)* 4.125 Average GSM MOS value 3.54

PowerPoint Presentation:

2G-3G interworking targets 2G-3G interworking principles 2G-3G interworking solutions 2G-3G interworking implementation solutions suggested 2G-3G subscribers’ demand and technology support 2G-3G co-location and interference issues

Analysis of the need for 2/3G co-location construction:

39 Analysis of the need for 2/3G co-location construction m Reduce space of equipment room, and need of antenna feeder Reduce project construction difficulty, and speed up project construction progress Save costs Transmission sharing Layout of 2G site may not guarantee the best quality of 3G network. Some solutions may lead to deteriorated loss. Interference isolation needs to be considered. The original 2G network performance may be influenced. Advantages Disadvantages GSM and 3G co-location is based on GSM1800 and this guarantees continuous coverage of video phone service. According to overseas network construction experience of ZTE, 2/3G co-location can help carriers to build a network with low costs but in a high speed. Statistics of 2/3G co-location proportion of overseas carriers Comparison of GSM and 3G coverage performance (dense urban areas)

Antenna and feeder design solution 1 — 2/3G independent antenna and feeder:

40 Antenna and feeder design solution 1 — 2/3G independent antenna and feeder Site of S hang Bu Industry and Trade Mansion in Huaqiangbei in Shenzhen Site of Heng Xun Communications building in Shenzhen GSM 900 3G GSM 900 GSM 1800 3G Advantages 1. It doesn’t influence the original system. 2. Optimization adjustment of each system is totally independent. Disadvantages The costs is high, because each system needs an additional antenna and feeder. Application scenarios 1. There is enough installation space and isolation space between the base station and the antenna. 2. The additional costs of installation pole and antenna is controllable. When a new antenna and feeder is added, the configuration of antenna azimuth and antenna downtilt parameters can refer to that of 2G system so as to guarantee the two systems cover the same range. In other words, “2/3G networks are integrated into one network”.

Antenna and feeder design solution 2 — 2/3G use a same feed line but a different antenna:

41 Antenna and feeder design solution 2 — 2/3G use a same feed line but a different antenna WCDMA GSM 900/ PCS 1800 A site in Hong Kong Advantages 1. The optimization adjustment of each system is totally independent. 2. It saves investment of feed line. Disadvantages The combiner causes extra loss, and this influences the original system coverage. Application scenarios The feed lines’ installation space and length is a major impact on rent costs.

Antenna and feeder design solution 3 – 2/3G use a same feed line and a same antenna:

42 A multiport wide beam antenna, whose downtilt can be adjusted, is recommended so as to guarantee relatively independent optimization adjustment of each system. Antenna and feeder design solution 3 – 2/3G use a same feed line and a same antenna A site in Hong Kong (six ports and tri-band antenna) Advantages It saves investment of feed lines. Disadvantages 1. The combiner causes extra loss, and this influences the original system coverage. 2. Since the antenna is shared, it makes RF optimization adjustment for each system more difficult. So intersystem coordination is needed. Application scenarios There isn’t enough installation space and isolation space between the base station and the antenna.

Antenna and feeder design solution 4 – 2/3G use a same antenna and a different feed line:

43 Antenna and feeder design solution 4 – 2/3G use a same antenna and a different feed line Advantages 1. It saves the investment for antenna and feeder. 2. It avoids the use of combiner, and the loss caused by it. Disadvantages Since the antenna is shared, it is more difficult to do RF optimization adjustment for each system. So intersystem coordination is needed. Application scenarios There isn’t enough installation space and isolation space between BBU and the antenna. RRU is directly installed under the multiport wide beam antenna, this method saves the investment for a combiner and avoids the loss caused by it. Improvement of path loss Coverage area improvement % 1dB 7% 2dB 14% 3dB 22% 4dB 30% 5dB 40% A site of Gang A o Shopping Mall in Huaqiangbei in Shenzhen (GSM1800+WCDMA) If 7/8’ feed line is at 2100MHz frequency band, 100 meters’ loss is 6.3 dB. As to China Unicom’s equipment room environment for present network, the proportion of feed lines which are longer than 50 meters is not small, especially in dense urban areas, the proportion is larger. However, RRU solution can avoid this kind of loss.

Summary of the adoption of a wide beam antenna:

44 Summary of the adoption of a wide beam antenna Possible influences over the original network caused by the use of a wide beam antenna Directional antenna Isotropic antenna Interference degradation In areas where there are dense sites, the slight change of antenna indicator will not have much influence over network coverage performance. Directional broadband antenna can be adopted to replace narrowband antenna without any negtive impact. After the replacement of antenna, the primary service area of the cell may change. The traffic attribution of the edges of the original cell may change, and then influence the load distribution of the cell. For those areas where there is the coverage performance degradation, the traffic may be lost. An “accidental problem”: After the adoption of a wideband antenna, there is a slight 5dB effect interference degradation.

Interference control principle for wireless communications:

45 Interference control principle for wireless communications Mutual interference between different communication systems (interference dead zone) ZTE emulation research The purpose of interference protection and control is not to totally eliminate the interference , but to control the interference at an acceptable level with reasonable costs so as to guarantee the normal operation of different communication systems. The basic solution for solving the problem of interferences from different wireless communication systems is frequency government and standardization of equipment standard specifications. Since the spectrum resources decrease gradually, it is more difficult to do interference protection control. When 3GPP establishes the technical specifications for 3G equipment, the interference with the present equipment has been fully considered, which normally satisfies30dB base station space isolation. However, during the time when the other existing networks (GSM and PHS and so on) are constructed, it is not possible to take into consideration the future networks like 3G. So the interference with 3G is inevitable, and this must be solved in construction.

2/3G mutual interference main consideration (1) — GSM900/1800:

46 2/3G mutual interference main consideration (1) — GSM 900/1800 According to the theoretical analysis, based on 3PP protocol, the blocking requirement of WCDMA to GSM, or WCDMA to GSM1800, is 43dB. The intermodulation isolation of GSM1800 to WDCMA is 94dB. Since WCDMA duplexer has 80dB out-band rejection, 94dB intermodulation isolation only needs 12dB spatial separation, so it can be completely neglected. Similarly, GSM1800 has 80dB out-band rejection, so the blocking interference can be neglected. 30dB isolation is enough to satisfy the mutual interference of WCDMA2100, GSM900/1800 the isolation design for multi-band antenna port is 30dB. Interference mechanism 3GPP theoretical isolation ( dB ) WCDMA to GSM1800 GSM1800 to WCDMA WCDMA to GSM900 GSM900 to WCDMA Spurious isolation 25 28.87 25 28.87 Blocking isolation 43 30 35 30 Intermodulation isolation -- 94 -- 94 Duplexer 80dB No influence after filtering 30dB

Practical engineering solution for GSM-3G interference coexistence:

47 Practical engineering solution for GSM-3G interference coexistence No interference coexistence can be realized by drawing on the rich overseas 3G engineering experience, and making use of the excellent anti-interference performance indicator of ZTE 3G equipment. For 65 degree horizontal beamwidth sector antenna, the vertical isolation should be less than 0.2 meter, and the horizontal isolation should be less than 0.4 meter. 3G independent antenna and feeder, spatial isolation solution 2/3G independent feed line, replacement of wide beam antenna solution The isolation of multiport wide beam antenna is relatively low, 30dB isolation between different dipoles can guaranteed, which satisfies the isolation indicator described above.900M, 1800M, and 2100M can share an antenna. A G/D/U tri-band antenna of Tian Di Hotel site in Shenzhen Spatial isolation of a site in Huaqiangbei in Shenzhen Note: For a wide beam antenna, its interference with PHS, and 1.9G CDMA decreases by 5dB!

Summary of interference:

48 Summary of interference Interference of GSM900, and GSM1800 is not the main problem. Interference of PHS, and CDMA1.9G of some areas must be solved during the construction of WCDMA network. Each area needs to consider its actual situation, and offers instructive suggestions about interference and makes preparations as soon as possible. - National policy of radio frequency spectrum; improvement of old equipment indicator

Summary of 2G – 3G network sharing operation:

49 Summary of 2G – 3G network sharing operation Result of 2G – 3G integration - One Radio Network Network interworking Service, load, and subscriber interworking System equipment, terminals Terminals System equipment: CN 、 Node B ; RNC/BSC and network management Project construction and network maintenance Site location  coordination/sharing Feeders and antennas  coordination/sharing Power transmission  sharing

authorStream Live Help