 EDGE network (simplified) EDGE NETWORK PLANNING 6.3 EDGE NETWORK PLANNING The radio network planning process is similar to that for GSM and GPRS networks. How- ever, because of minor hardware and software changes in the existing network, that lead to major changes in network performance, the network planning parameters change quite a bit. Owing to increased bit rates, transmission planning undergoes a major change with introduction of the concept of a dynamic Abis interface. In contrast, core network planning is virtually the same as for a GPRS network. 6.3.1 Radio Network Planning Coding Schemes As already mentioned, the EDGE system is an enhancement to the existing GPRS system. There are nine modulation and coding schemes (MCS-1 to MCS-9) that provide different throughputs, as shown in Table 6.1. The MCS scheme carries data from 8.8 kbps to 59.2 kbps on the existing GSM carrier of 270.833 kbps. For coding schemes MCS-1 to MCS-4, modulation is still GMSK; for MCS-5 to MCS-9 it is 8-PSK. Based on this coding scheme, a data rate of 473 kbps (8 bits X 59.2 kbps) can be achieved. Though GMSK is a more robust scheme, 8-PSK gives more data throughput. However, the increased data rate comes at the price of decreased sensitivity of the system. This has an impact on network planning. Another advantage in EDGE networks is that the switching between different coding schemes can take place easily, which was not possible in a GPRS network. When data trans- mission takes place in a GPRS coding scheme, it is not possible to switch the coding scheme on reception failure, SO the re-transmission takes place with exactly the same protection as for its initial transmission. In EGPRS, it is possible to change the MCS, i.e. the data block can be sent again but with better protection than for its initial transmission. This is done through a process called link adaptation. One more observation on the coding scheme is that the new set of GMSK coding is being used, e.g. CS-1 is equivalent to 8 kbps in GPRS networks (Chapter 5), with sim