Interactive cellular and cordless video telephony: State-of-the-art system design principles and expected performance

Abstract

Second-generation (2G) mobile radio standards have not been designed with video communications in mind, although the employment of error-resilient, constant-bit-rate proprietary video codecs over these systems is realistic. The third-generation (3G) systems I. STATE-OF-THE-ART SYSTEM COMPONENT DEVELOPMENTS A. Introduction and OutlineThe subject of mobile radio communications has reached a state of maturity over the past two decades, as indicated by the excellent monographs by Jakes This contribution attempts to summarize a range of recent advances in the field of bandwidth-efficient wireless video communications. In this section, we commence our discourse with a brief overview of the wireless scene and, in particular, by considering the video transmission capabilities of the existing and future wireless systems. The geographical variation of the cellular channel capacity is characterized by Section II, as a motivation for invoking burst-by-burst adaptive transceivers [27]- [29]. The nature of co-channel interference (CCI)-which is the most dominant channel impairment in wireless systems-is the topic of Section III, where it is shown that the geographic variation of CCI justifies the employment of multimode transceivers, which are discussed in Section IV. Low-rate video compression aspects are reviewed in Section V, and the performance of the ITU H.263 codec is analyzed in some depth. Our discussions in Sections VI and VII are focused on the performance of reconfigurable video transceivers. Specifically, in Section VI, no power control is used-which is typically the case in cordless telephones, such as DECT and CT2-while in Section VII, power control is employed, which is characteristic of cellular systems, such as GSM [30], etc. Section VIII proposes a near-instantaneously adaptive or burst-by-burst adaptive code-division multiple-access (CDMA) scheme, which can be invoked in the context of the forthcoming 3G systems, in order to enhance their performance. Lastly, our discussions are concluded in Section IX with a range of system design guidelines. Let us now commence our overview of the range of existing and forthcoming wireless systems and their video transmission capabilities. B. Second-Generation (2G) Wireless SystemsThe existing 2G wireless systems now constitute a mature technology. Although they have not been designed with video communications in mind, with the advent of the specially designed error-resilient, fixed-rate video codecs [27]-[35] proposed by Streit et al., it is nonetheless realistic to provide videophone services over these low-rate schemes. For low-latency interactive videophony these systems have

Comparative study of turbo decoding techniques: an overview

“…Other efforts are in the field of incorporating turbo codes in practical speech and video systems. A range of application examples can be found in the context of interactive and broadcast video systems as well as local area networks in [4] and [5], and in [42]- [52]. In short, an exciting era at the 50th anniversary of Shannonian information theory, witnessing the first practical systems performing close to information theoretical limits, stimulating the research community to aspire to similar performance over dispersive, fading wireless channels.…”

Near-Capacity H.264 Multimedia Communications Using Iterative Joint Source-Channel Decoding

“…Since the early days of wireless video communications [74][75][76] substantial further advances have been made both in the field of proprietary and standard-based solutions [77,78]. Furthermore, the discovery of turbo codes [52,79] made it practical to achieve transmission close to the Shannon limit at a moderate computational complexity and delay.…”

EXIT-Chart Optimized Short Block Codes for Iterative Joint Source and Channel Decoding in H.264 Video Telephony

“…days of wireless video communications [3]- [6], substantial further advances have been made in the field of both proprietary and standard-based solutions [7], [8]. Furthermore, the joint optimization of different functions such as joint source and channel decoding (JSCD) has gained considerable attention.…”

“…On the other hand, a novel irregular variable length coding (IrVLC) scheme designed for near-capacity joint source and channel coding was proposed in [17]. Likewise, Hanzo et al [7] advocated the employment of state-of-the-art high-speed-packet-access-style [18] burst-byburst adaptive transceivers for interactive cellular and cordless video telephony, which are capable of accommodating 0018-9545/$26.00 © 2009 IEEE time-variant channel quality fluctuation of wireless channels. An iterative-source-and-channel-decoding-aided irregular convolutional coded videophone scheme using reversible variablelength codes and the maximum a posteriori (MAP) [19] detection algorithm was proposed in [20].…”