The study of performance enhancement for integrated voice/data wireless networks by link adaptation

Link adaptation (LA) allows the selection of proper coding/modulation scheme in order to cope with the radio channel quality variation. The efficiency of LA is generally demonstrated with the link level performance in terms of spectral efficiency (b/s/Hz/Sector) from the transmitter-to-receiver pair's aspect. Few studies exist in literature that considers LA when the performance of a wireless network was assessed by means of a teletraffic analysis. In this paper, we estimate the data performance enhancement of having LA in an integrated voice/data wireless system from a cell's point of view. The analytical system is GSM/GPRS where data service supports four coding schemes; the link level performance is simulated using the Rudimentary Network Emulator (RUNE) and the system level performance is obtained through queueing analysis. Analytical results show that both the data throughput and delay are improved. In our study, the percentage of four coding schemes used, from CS-1 to CS-4, are 5, 8, 29, and 58%, and the packet throughput shows an increase of 28.6% higher and the packet delay shows decrease of 26% less than those in a fixed CS-2 coding system.