The merger of a single oscillating-beam smart antenna and MC-CDMA: transmit diversity, frequency diversity and directionality

Abstract

In this paper, we introduce a novel merger of a single smart antenna array and MC-CDMA (multi-carrier code division multiple access) systems. Here, all carriers in the MC-CDMA system are applied to one smart antenna at the base station (BS). Applying proper time-varying phases to array elements of the smart antenna array, the beam pattern is carefully controlled to generate a mainlobe at the position of the intended user and small oscillations in the beam pattern. This beam pattern oscillation creates a time varying channel with a controllable coherence time and a time diversity benefit at the receiver. Employing MC-CDMA with the proposed antenna array at the BS, we achieve: (1) directionality which supports space division multiple access (SDMA); (2) a time diversity gain using only a single antenna at the receiver in the mobile unit; and (3) increased capacity and performance via MC-CDMA's ability to support both code division multiple access and frequency diversity benefits. Hence, merging MC-CDMA and BS single antenna array in an innovative fashion, we achieve high performance at the mobile via joint frequency-time diversity, and high network capacity via joint space-code division multiple access.