On QAM Speech Transmission Schemes for Microcellular Mobile - PCNs

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Description/Abstract

Abstract. On the way towards third generation personal communication networks (PCN) the deployment of 16-level quadrature amplitude nlodulation (QAW schemes is investigated via flat microcellular Rayleiph-fading mobile radio channels having mild co-channel interference with and without diversity. Our proposed differentially coded non-coherent 16-QAM scheme requires no pilot symbol assistance. no automatic gain control (AGC) and no carrier recovery. High speech quality associated with a mean opinion score of about four (MOS = 4.0) is ensured at a signalling rate of 6.1 kBd for channel signal to noise ratios tSNR) above 30 - 25 dB and signal to interference ratios (SIR) above 75 - 30 dB by the 13.4 kbit/s medium complexity resular pulse excited (RPE) speech codec, when carefully matched twin-class low complexity binary Bose-Chaudhuri-Hocquenghem (BCHI error correction coding and 16-QAM combined with second order diversity are deployed. The overall speech delay is about 10 Ins and the user bandwidth is 9.3 kHz. which allows us to accommodate 2 1 users in a 300 kHz channel slot.