Radio Resource Allocation for OFDMA Systems in High Speed Environments

In high speed train (HST) system, real-time multimedia entertainments are very important applications in which a data stream often contains packets with different quality of service requirements. For example, video stream encoded with scalability contains the base layer packets with high quality (HQ...

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Bibliographic Details
Published in:IEEE journal on selected areas in communications 2012-05, Vol.30 (4), p.748-759
Main Author: Zhu, Huiling
Format: Article
Language:English
Subjects:
Allocations
Bit error rate
Bit rate
Channel estimation
Channels
chunk-based allocation
data packets with multiple BER requirements
Doppler effect
Empirical analysis
High speed
high speed trains
minimization of transmit power
Modulation
OFDM
OFDMA systems
Packets (communication)
Resource allocation
Resource management
Streams
Studies
Wireless communication
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Summary:In high speed train (HST) system, real-time multimedia entertainments are very important applications in which a data stream often contains packets with different quality of service requirements. For example, video stream encoded with scalability contains the base layer packets with high quality (HQ) bit error rate (BER) requirement and enhancement layers' packets with low quality (LQ) BER requirement. When a conventional allocation approach, which only considers one BER constraint for one data stream, is applied to orthogonal frequency division multiple access (OFDMA) systems, the BER constraint will be the strictest one among multiple requirements from different types of packets, which leads to inefficient allocation when each data stream has multiple BER requirements. This paper aims to develop novel resource allocation approach by considering multiple BER requirements for different types of packets in one data stream. In order to not only simplify the resource allocation, but also to compensate for the channel estimation error caused by Doppler shift in the HST environment, a proper number of contiguous subcarriers are grouped into chunks and spectrum is allocated chunk by chunk. Simulation results show that the developed resource allocation scheme outperforms the conventional scheme, particularly when the BER ratio of HQ packets to LQ packets is larger than one. Furthermore, in order to reduce the complexity of resource allocation further, an empirical allocation scheme is proposed to allocate better chunks to HQ packets. It is shown that the performance of the empirical allocation scheme is quite close to that of the optimal scheme.
ISSN:0733-8716
1558-0008
DOI:10.1109/JSAC.2012.120509