Multilevel Control Signaling for Hybrid ARQ in the UMTS HSDPA System

Chang-Rae JEONG  Seung-Hoon HWANG  Hyuck-Chan KWON  Younghoon WHANG 

Publication
IEICE TRANSACTIONS on Communications  Vol.E92-B  No.1  pp.334-337
Publication Date: 2009/01/01
Online ISSN: 1745-1345
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technologies
Keyword: 
hybrid ARQ,  multilevel control signaling,  UMTS,  HSDPA, 

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Summary: 
In this paper, we propose and analyze a multi-level acknowledgement scheme for hybrid ARQ (H-ARQ) systems, which modifies the general ACK/NAK signals to represent multilevel information. For instance, the other signals except the ACK/NAK signals may be used for scheduling of retransmission in the H-ARQ scheme, which results in increasing the resolution of the uplink channel estimation signals. Simulation results demonstrate that when the retransmission interval is set to the optimal length, the proposed H-ARQ scheme shows a 0.5-2 dB gain with properly selected parameters.