lying more PCMs required per site, with additional cost. Thus, the number of time slots planned for DAP should be a balance between the desirable throughput and cost. Example 1: Dynamic Abis Dimensioning for One Single Site Consider a single site with configuration 1 + 1 + 1. It should be able to deliver a data rate of 59.2 kbps (i.e. MCS-9) by using two radio time slots. What is the number of time slots that should be reserved for dynamic Abis so that the Abis data rate reduction factor is less than 1%; and how many Els (PCMs) are required for the BTS-BSC connection? (PCMs are known as Els (in ETSI) and T1s (in ANSI) standards.) Signalling is on the GSM layer. As one user is able to use two radio time slots to get a data rate of 59.2 kbps, four users can use eight time slots at a given time. This implies 4 data Erlangs. EGPRS territory = 8 Data rate = 59.2 kbps Data rate after C/I = 40 kbps For a DAP = 12 TSL on Abis Based on the binomial distribution formula stated, the results are as follows: The sharing probability of the DAP is only 3.176%. The Abis data rate reduction is less than 1%, which means that the Abis will not be a bottleneck for the throughput of the air-interface. The average throughput per RTSL, limited by radio and Abis, is 19.88021. The Abis data rate reduction is 0.60%. Now, as three transceivers need only 3 X 2.25 = 6.75 time slots, and the DAP will require 12 time slots, the total number of time slots needed will be 6.75 + 12 = 18.75. Apart from this, TSO and TS31 can be kept for management, etc. Thus, one E1 will be sufficient for connecting this site to the BSC. 6.3.4 Example of RNP + TNP Dimensioning Anexample of the combined result of radio and transmission network dimensioning is shown in Table 6.2. This is the result of a dimensioning case where the maximum throughput per user is 6kbps, but owing to C/I limitation the acceptable user throughput is reduced to 64 kbps per user. The dimensioning is done for coding scheme MCS-7. The EDAP size is nine time slots. NETWORK OPTIMISATION Table