Characterization of a Class of Error Correcting Frames for Robust Signal Transmission over Wireless Communication Channe
- PDF / 1,000,460 Bytes
- 13 Pages / 600 x 792 pts Page_size
- 88 Downloads / 214 Views
Characterization of a Class of Error Correcting Frames for Robust Signal Transmission over Wireless Communication Channels Gagan Rath IRISA, INRIA, Campus de Beaulieu, 35042 Rennes, France Email: [email protected]
Christine Guillemot IRISA, INRIA, Campus de Beaulieu, 35042 Rennes, France Email: [email protected] Received 14 July 2003; Revised 24 May 2004 Joint source-channel coding has been introduced recently as an element of QoS support for IP-based wired and wireless multimedia. Indeed, QoS provisioning in a global mobility context with highly varying channel characteristics is all the most challenging and requires a loosening of the layer and source-channel separation principle. Overcomplete frame expansions have been introduced as joint source-channel codes for erasure channels, that is, to allow for a signal representation that would be resilient to erasures in wired and wireless channels. In this paper, we characterize a class of frames for error correction besides erasure recovery in such channels. We associate the frames with complex number codes and characterize them based on the BCH-like property of the parity check matrices of the associated codes. We show that, in addition to the BCH-type decoding, subspace-based algorithms can also be used to localize errors over such frame expansion coefficients. When the frame expansion coefficients are quantized, we modify these algorithms suitably and compare their performances in terms of the accuracy of error localization and the signal-to-noise ratio of the reconstructed signal. In particular, we compare the frames associated with lowpass DFT, DCT, and DST codes, which belong to the defined class, in terms of their error correction efficiency. Keywords and phrases: frame theory, error correction, compression, block transforms, wireless communication.
1.
INTRODUCTION
The development of “Beyond 3G” (B3G) or “4G” networks and applications with all-IP-based seamless and ubiquitous service provisioning across heterogeneous infrastructures presents a number of technological challenges. Providing IP-based audio and video communications at the same, or at least comparable, “carrier class” and bandwidth efficiency as the corresponding circuit-switched subsystems of 3G and 2G remains an issue to be solved. There is a growing awareness and understanding that efficient QoS provisioning in a global mobility context with highly varying channel characteristics (bandwidth, throughput, error rates, fading, and erasure characteristics, etc.) requires a loosening and a rethinking of the end-to-end and layer separation principle. In particular, it is becoming a common understanding that vertical cross-layer cooperation may be beneficial because of both of the error and erasure resilience capabilities of emerging coding technology and of the idiosyncrasies of the wireless links. Both the link layer including the radio bearer
system and the higher layers will indeed benefit from QoSrelated information exchange. The robust header compression (ROHC) framework [1], and the new UD
Data Loading...