On Information Rates of Time-Varying Fading Channels Modeled as Finite-State Markov Channels

Date

2008

Authors

Sadeghi, Parastoo
Rapajic, Predrag

Journal Title

Journal ISSN

Volume Title

Publisher

Institute of Electrical and Electronics Engineers (IEEE Inc)

Abstract

We study information rates of time-varying flatfading channels (FFC) modeled as finite-state Markov channels (FSMC). FSMCs have two main applications for FFCs: modeling channel error bursts and decoding at the receiver. Our main finding in the first application is that receiver observation noise can more adversely affect higher-order FSMCs than lower-order FSMCs, resulting in lower capacities. This is despite the fact that the underlying higher-order FFC and its corresponding FSMC are more predictable. Numerical analysis shows that at low to medium SNR conditions (SNR ≲ 12 dB) and at medium to fast normalized fading rates (0.01 ≲ fDT ≲ 0.10), FSMC information rates are non-increasing functions of memory order. We conclude that BERs obtained by low-order FSMC modeling can provide optimistic results. To explain the capacity behavior, we present a methodology that enables analytical comparison of FSMC capacities with different memory orders. We establish sufficient conditions that predict higher/lower capacity of a reduced-order FSMC, compared to its original high-order FSMC counterpart. Finally, we investigate the achievable information rates in FSMC-based receivers for FFCs. We observe that high-order FSMC modeling at the receiver side results in a negligible information rate increase for normalized fading rates fDT ≲ 0.01.

Description

Keywords

Keywords: Acoustic intensity; Channel capacity; Decoding; Fading (radio); Markov processes; Signal to noise ratio; Time varying systems; Finite-state Markov channels; Higher-order; Information rates; Fading channels Channel capacity; Fading channels; Finite-state Markov channels; Markov processes

Citation

Source

IEEE Transactions on Communications

Type

Journal article

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2037-12-31