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Chapter 6Optimisation of CRA using adaptive CSAs p6.2.3.3 Performance comparison of Enhanced-CSAsIn order to provide a complete performance comparison between the Forced andVariable CSAs, three different traffic configurations will be analysed: 64 kbps IPstreams, 32 kbps IP streams and 41.7 kbps mixed traffic.A summary of the maximum system performance produced by each CSA for Internettraffic is presented in Table 6.2. A detailed comparison for mixed traffic is shown inFigures 6.7 to 6.10.For Internet traffic at 32 kbps per station, the best system performance was achieved bythe Forced-CSA. Three different configurations were analysed using this scheme (asindicated in Table 6.2). The highest system throughput (about 52% of the cc) and thelowest mean access delay (of 584 ms) was achieved by both allocating 2 FSs after acollision and defining at least 2 CSs per signalling frame, at approximately 53% of thechannel capacity (produced by 51 stations). In addition, the average number of CSsneeded per request resulted in 2.819, which is quite close to the optimum e(=2.718) witha maximum deviation under 1% of the cc between simulation and theoretical results.Table 6.2 – Maximum system performance for Internet traffic and different CSAs.InternetTraffic32 kbpsCSASimpleSimpleMin. CSsPer Sign.FrameMaximumThroughput(%)Mean AccessDelay(ms)CSs perRequestOfferedLoad(%)ActiveStations3 46.8 3099.98 3.96344 52.3501 515 48.0 2004.82 3.57891 51.3815 51Forced-FSs 1 3 51.1 1284.42 2.87358 53.1611 51Forced-FSs 2Forced-FSs 2VariableVariable2 51.5 584.026 2.81989 52.8379 513 51.0 1090.09 2.91893 53.0158 512 47.9 2628.13 3.68146 53.153 513 47.8 2195.96 3.6845 52.9651 5164 kbpsSimple 4 50.6 1226.38 3.07588 52.5 25Forced-FSs 1 3 50.7 913.49 3.01059 51.7 25Forced-FSs 2 2 50.6 494.56 3.01297 51.3 25Forced-FSs 2 3 49.8 416.05 3.15268 50.7 25Variable 2 50.8 777.72 2.95227 51.9 25Variable 3 51.3 624.79 2.87162 52.1 25The shaded rows present the CSA with optimum system performance.6-12