Channel estimation in OFDM systems using Coherence Distance Regions

Communication systems users increasingly anticipate faster and more reliable services. By acquiring more information about geographical areas, communication system operators can account for environmental effects, reducing the need for transmitting known symbols used for channel estimation (pilots), hence improving bandwidth utilization and channel equalization. One method for removing channel estimation is to store the Channel Impulse Response (CIR) for every possible location. However, this is impractical. In this paper, we present a novel method of producing a coherence distance region (CDR). A CDR stores a geographical contour and a single Channel Impulse Response (CIR), which can be employed by users to perform accurate channel estimation, regardless of their position within the region. Numerical simulations, using an environment resembling the Extended Pedestrian A model, was used to demonstrate a method of defining a CDR’s contour. We demonstrate that using a CDR produces an improved bit error rate over traditional channel equalization methods using pilots. Results indicate that using CDRs is a promising method of improving communications efficiency by enabling a large geographical area to be described by a small number of these discrete regions, each with a single representative CIR.