6.4　Design of Radio Access Network Capacity

6.4.1　Radio access network capacity design shall abide by the following principles:

1　Network capacity shall be designed to satisfy traffic needs in the project lifecyle，with due considerations given to both reality and sustainability.The capacity shall meet not only current engineering needs but also future development needs.

2　Traffic load，service types，service quality requirements，up-and down-link data throughput shall be jointly considered to determine the capacity of individual Node B.

3　Resources of WCDMA radio access network capacity include power，CE（Channel Element）and HSDPA code，where each aspect may become a capacity bottleneck and must be considered during Node B capacity calculation.

4　Actual traffic proportion and density shall be used as the basis for the network capacity design，with considerations of factors in social and economic development.

5　Investigation and prediction of traffic density within the coverage of the radio access network shall be performed to give an estimate of traffic density for a scheduled future period that is to be used as the basis for network construction.

6.4.2　Methods for radio access network capacity expansion:

1　Increase CE deployment；

2　Increase HSDPA codes；

3　Increase amplifier power；

4　Add new carrier；

5　Split cells，increase the number of BSs or cells；

6　Adopt microcell and picocell structure.

A feasible expansion plan shall be obtained from a comparative study from technical and economic perspectives of the above methods.

6.4.3　Multiple carrier design shall abide by the following principles:

1　Hard handover shall be optimized to reduce call drops and avoid making high-traffic cells become border cells of hard handover；

2　Isolated multiple carrier BSs shall be avoided by implementing continuous coverage for a certain range to reduce hard handover when increasing carriers；

3　Reasonable residing and access strategies for multiple carrier areas shall be adopted to ensure the balance of the traffic load of each carrier and the network load.

6.4.4　The capacity target and user model of a WCDMA radio access network shall be determined by considering the traffic and data throughput together with parameters with uneven weight of different service and coefficient of fluctuation.