Performance of a GSM-like system adopting the fractional loading technique

This paper aims at assessing performance of the 'fractional loading' technique in FDMA/TDMA systems. This technique keeps channel occupancy below a given threshold in order to control the overall interference in the system thus being capable of ensuring the desired grade of service. This implies that a call may get blocked due to excessive interference, even in the presence of hardware resources available to serve that call (also known as 'admission control' policy). Therefore, this technique tends to introduce in TDMA systems the 'soft capacity' concept which is peculiar to CDMA systems. The 'fractional loading' technique can be associated with different channel allocation strategies. Suitable dynamic channel allocation (DCA) algorithms call be employed in order to optimise the overall radio resource management; alternatively, also the usual fixed channel allocation (FCA) approach can be considered. In addition, the 'fractional loading' technique can be associated with frequency hopping. In this paper, performance of a GSM-like system adopting the 'fractional loading' technique is analysed by means of system level simulations considering an ideal reference scenario (regular layout of hexagonal cells equipped with omnidirectional antennas) and taking into account different channel allocation strategies. Moreover, the advantages of this technique under non-homogeneous traffic load are addressed.