In this paper, resource allocation problem for multicast service in OFDM-based wireless cellular networks is investigated and a coding-based opportunistic scheduling scheme is proposed. In the proposed scheme, accordi...
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ISBN:
(纸本)9781467309899
In this paper, resource allocation problem for multicast service in OFDM-based wireless cellular networks is investigated and a coding-based opportunistic scheduling scheme is proposed. In the proposed scheme, according to frequency resource and time resource, layered coding and erasure-correction coding are adopted, respectively. layered coding divides the data into base layer and enhancement layer, which transmits the data in different rates to maximize the system capacity;erasurecorrection coding compensates for the possible packet loss due to instantaneous channel information. To complete subcarrier allocation and bit loading for the coding-based scheme, a practical algorithm is designed. As only the users;mean channel gains are required, the proposed scheme reduces the overheads required for instantaneous channel information and is suitable for a fast time-varying fading environment. Numerical results show that the coding-based scheme can get significant performance improvement compared with the scheme without coding.
A new approach to hybrid digital-analog (HDA) video transmission over orthogonal frequency division multiplexing (OFDM) channels is presented. The goal is to achieve the best video quality by optimal power allocation,...
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ISBN:
(纸本)9781538646595
A new approach to hybrid digital-analog (HDA) video transmission over orthogonal frequency division multiplexing (OFDM) channels is presented. The goal is to achieve the best video quality by optimal power allocation, when the OFDM sub-channels have unequal and time-varying signal-to-noise ratios (SNR). In this method, the quantization error of a video encoder is superimposed on digital quadrature amplitude modulation (QAM) symbols. A solution to the power allocation problem is presented. Experimental comparisons with layered video coding and adaptive modulation shows that the proposed HDA approach is able to achieve a better video quality most of the time, particularly whenever there is a high motion content.
In this paper, we explore the convergence of the caching and streaming technologies for Internet multimedia. The paper describes a design for a streaming and caching architecture to be deployed on broadband networks. ...
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ISBN:
(纸本)9781581131987
In this paper, we explore the convergence of the caching and streaming technologies for Internet multimedia. The paper describes a design for a streaming and caching architecture to be deployed on broadband networks. The basis of the work is the proposed Internet standard, Real Time Streaming Protocol (RTSP), likely to be the de-facto standard for web-based A/V caching and streaming, in the near future. The proxies are all managed by an `Intelligent Agent' or `Broker' - this has been designed as an enhanced RTSP proxy server that maintains the state information that is so essential in streaming of media data. In addition, all the caching algorithms run on the broker. Having an intelligent agent or broker ensures that the `simple' caching servers can be easily embedded into the network. However, RTSP does nor have the right model for doing broker based streaming/caching architecture. The work reported here is an attempt to contribute towards that end.
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