Channel equalisation at the mobile equipment by spectral processing without cyclic prefix

Availability of high-throughput, multicast/multiple-routing communication links in the presence of multipath fading channels is an important item for multi-hop and ad-hoc networks. To this purpose, channel equalisation by spectral processing is examined as an appealing enabling tool, as its exploits the low processing complexity of FFT. Spectral equalisation, which in OFDM is enabled by a cyclic prefix, is in principle applicable also to other access schemes like TDMA and CDMA; however several of existing schemes (e,g, standards like FDD HSDPA in UMTS cellular networks) do not comprise a cyclic prefix. This paper introduces BCSE (bias controlled spectral equaliser), a novel spectral equaliser not requiring a cyclic prefix; its performance, evaluated for UMTS FDD HSDPA, for SISO and 2×2 MIMO spatial multiplexing, is the same as when employing CP, with only a moderate increase of processing load and with a small duration processing window, which depends on the channel time spread. When used for UMTS TDD, FDD, FDD-HSDPA, BCSE requires no standard modification.