Abstract-In this work we introduce error control algorithms for multicast delivery in 3G cellular networks. For efficiency reasons, the delivery of multicast flows is usually achieved by allocating a common channel in the forward direction. This enables multiple users to be served by a single physical resource. However, different users are affected by independent channel error processes and new techniques, different from plain ARQ, have to be found to perform error recovery. These new algorithms are needed to deliver the multicast flow in an efficient manner and to enable a reliable, performant and network operator inexpensive multicast service. In the paper different hybrid ARQ algorithms for the error recovery of multicast flows over common channels are proposed and their performance is evaluated both analytically and by simulation. The proposed solutions have been found to be effective and advantageous over plain ARQ techniques. At the end of the paper, results on the achievable video quality are reported for the multicast video streaming case by considering the H.263 video coding format.
Video services are expected to account for a large portion of the traffic in future wireless networks. Therefore realistic traffic sources are needed to investigate the network performance of future communication protocols. In our previous work we focused on video services for 3G networks. We provided a publicly available library of frame size traces of long MPEG-4 and H.263 encoded videos in the QCIF format resulting in low bandwidth video streams. These traces can be used for the simulation of 3G networks. Some future communication systems, such as the WLAN systems, offer high data rates and therefore high quality video can be transmitted over such higher speed networks. In this paper we present an addition to our existing trace library. For this addition we collected over 100 pre-encoded video sequences from the WEB, generated the trace files, and conducted a thorough statistical evaluation. Because the pre-encoded video sequences are encoded by different users they differ in the video settings in terms of codec, quality, format, and length. The advantage of user diversity for encoding is that this reflects very well the traffic situation in upcoming WLANs. Thus, the new traces are very suitable for the network performance evaluation of future WLANs.
Abstract-This paper proposes a low complexity, high speed, regular and flexible architecture for VLSI implementation of Reed Solomon decoder. With this architecture the error locator and error evaluator polynomials of the decoder can be computed in parallel and the same datapath can be reused to realize a partially pipelined parallel RS decoder. By architecture reuse the number of required resources for the RS decoder can be adjusted to a specific application, while maintaining internal parallel computation of each RS procedure. The resulting architecture contains one type of program element, which simplifies test and fabrication.
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