XQUAL 6 6.4% < BER < 12.8% RXQUAL 7 12.8% < BER Radio Network Planning and Optimisation Table 2.12 C/N versus coding scheme Coding scheme Nonhopping [dB] frequency hopping [dB] BLER < 10% BLER < 10% BLER < 10% BLER < 10% The radio link measurements, i.e. the reported RXLEV and RXQUAL values, are needed when per- forming handovers and power control. The radio link measurements are performed over a slow associated control channel (SACCH) multiframe, which consists of 104 TDMA frames in the case of full rate traffic channel (TCH). The 104 TDMA frames last for 480 ms. 2.5.2 Coverage Planning in EGPRS The coverage planning aspects of EGPRS implementation is centered around ensuring sufficient carrier- to-noise (C/N) ratios on both uplink and downlink to allow for successful data transmission across the coverage area. Each coding scheme defined for GPRS (and MCS for EGPRS) is suited to a particular range of C/N for a given block error rate (BLER). Generally, it is found that the higher the level of error protection, the lower the required C/N. Table 2.12 shows some sample simulation results for GPRS coding schemes. The objective of coverage planning is to provide a coverage area for both the uplink and downlink in a balanced way. This is achieved by calculating the link budget. The link budget calculations allow a comparison to be made between achievable cell ranges of EGPRS using different coding schemes and those on current GSM networks. As an input to the link budget, a number of key elements need to be established, some of which are: Transmitter output power (MS/BS); Receiver performance for different coding schemes (MS/BS); Antenna configurations (diversity). Relative Coverage Areas of GPRS Coding Schemes Due to the differing C/N requirements of the modulation coding schemes, the relative coverage area of each will obviously be different. It is useful to compare the relative predicted coverage areas of the coding scheme, in addition to the existing GSM voice service. Figure 2.19 illustrates coverage over a nominal