Performance analysis of fiber-fed microcellular networks using Π/4-DQPSK in a frequency-selective CCI-limited Nakagami fading environment

摘要

The use of wide-band and low-loss fiber-optic feeders to transfer the complex signal processing and control functions from the base station (BS) to a central control station (CCS) in a microcellular system, has attracted a great deal of attention. The optical feeder allows compact and cost-effective base stations, easier channel assignment control, and. flexible communication systems. This paper investigates the simultaneous influence of the effects of the wireless channel such as fading and cochannel interference (CCI) and the effects of the optical channel, like shot noise and intermodulation distortion, introduced by the laser diode on the bit error rate (BER) performance of a fiber-fed microcellular system using the Π /4-differential quadrature phase-shift keying (DQPSK) modem scheme. The wireless channel is assumed to be a frequency-selective, slow, and CCI-limited Nakagami fading channel. The BER performance of the system is studied under various channel conditions using an exact model and a simplified model and a comparative study with a nonfiber-fed system is carried out. The tradeoff between the system capacity and the BER performance in fiber-optic microcellular (FOM) systems is also discussed. The results obtained justify the application of fiber-optic feeders as the remoting infrastructure for future microcellular systems.