Reverse link erlang capacity of time-hopping/TDMA wireless communication systems

Abstract

In this paper, the performance analysis of a recently proposed multiple-access (MA) scheme for data communication via TDMA wireless channel in terms of Erlang capacity is carried out. The proposed MA scheme takes advantage of time-hopping (TH) within multiple frames of a time-division multiple-access (TDMA) system to provide access to the channel for network subscribers. First, a super-frame for the TDMA signaling is defined. Subsequently, a user is provided with an access code that is used to hop over the indicated TDMA super-frame, hereafter referred to as a TH frame. The assignment codes are those of the {0,1} family codes, recently exploited for fiber-optic code-division multiple-access (FO-CDMA) applications. It is assumed that each assignment code can guarantee no more than 1 hit in a superframe and that code synchronization exists between all users. For differential phase-shift-keying (DPSK) and M-ary frequency-shift-keying (MFSK) modulated THMA systems and when side information is available at the receiver, upper bounds on the overall symbol error rate are derived when the communication channel is impaired by slow frequency non-selective Rayleigh and Rician fading. The capacity of the proposed system is obtained in terms of Erlang/sector for reverse link and is compared to those of TDMA and CDMA systems. It is demonstrated that the power control requirement of the proposed THMA system is identical to that of a conventional TDMA system, and that the proposed system achieves an Erlang capacity identical to that of its CDMA counterpart