Theoretical study of link adaptation algorithms for adaptive modulation in wireless mobile communication systems

Adaptive modulation with varying data rate is an attractive scheme to increase the transmission data rate for mobile radio communications. The radio link adaptation (LA) algorithm is an important issue for such a system; however a theoretical analysis of LA algorithms has not previously been carried out. This paper presents a performance analysis of the LA algorithms for slow fading mobile radio channels. The LA algorithms based on the received signal level are studied; the expression of the radio link outage probability and transmission data rate are derived. The simulations were performed in the GSM communication environment, which gave identical results to the theoretical analysis. The results can be used to determine suitable LA algorithms for adaptive modulation under different conditions.