2 research outputs found
Analysis and Throughput Optimization of Selective Chase Combining for OFDM Systems
In this paper, we present throughput analysis and optimization of bandwidth
efficient selective retransmission method at modulation layer for conventional
Chase Combining (CC) method under orthogonal frequency division multiplexing
(OFDM) signaling. Most of the times, there are fewer errors in a failed packet
and receiver can recover from errors receiving partial copy of original frame.
The proposed selective retransmission method at modulation layer for OFDM
modulation requests retransmission of information corresponding to the poor
quality subcarriers. In this work, we propose cross-layer multiple selective
Chase combining (MSCC) method and Chase combining with selective retransmission
(CCWS) at modulation level. We also present bit-error rate (BER) and throughput
analysis of the proposed MSCC and CCWS methods. In order to maximize throughput
of the proposed methods under OFDM signaling, we formulate optimization problem
with respect to amount of information to be retransmitted in selective
retransmission in the event of packet failure. We present tight BER upper
bounds and tight throughput lower bounds for the proposed selective Chase
combining methods. The simulation results demonstrate significant throughput
gain of the optimized selective retransmission methods over conventional
retransmission methods. The throughput gain of the proposed selective
retransmission atmodulation layer are also holds for conventional for hybrid
automatic repeat request (HARQ) methods
Cross-layer Chase Combining with Selective Retransmission, Analysis and Throughput Optimization for OFDM Systems
In this paper, we present bandwidth efficient retransmission method employong
selective retransmission approach at modulation layer under orthogonal
frequency division multiplexing (OFDM) signaling. Our proposed cross-layer
design embeds a selective retransmission sublayer in physical layer (PHY) that
targets retransmission of information symbols transmitted over poor quality
OFDM sub-carriers. Most of the times, few errors in decoded bit stream result
in packet failure at medium access control (MAC) layer. The unnecessary
retransmission of good quality information symbols of a failed packet has
detrimental effect on overall throughput of transceiver. We propose a
cross-layer Chase combining with selective retransmission (CCSR) method by
blending Chase combining at MAC layer and selective retransmission in PHY. The
selective retransmission in PHY targets the poor quality information symbols
prior to decoding, which results into lower hybrid automatic repeat reQuest
(HARQ) retransmissions at MAC layer. We also present tight bit-error rate (BER)
upper bound and tight throughput lower bound for CCSR method. In order to
maximize throughput of the proposed method, we formulate optimization problem
with respect to the amount of information to be retransmitted in selective
retransmission. The simulation results demonstrate significant throughput gain
of the proposed CCSR method as compared to conventional Chase combining method.Comment: arXiv admin note: text overlap with arXiv:1503.0581