Performance of modulation-level-controlled adaptive-modulation under limited transmission delay time for land mobile communications

Kamio, Yukiyoshi; Sampei, Seiichi; Sasaoka, Hideichi; Morinaga, Norihiko

doi:10.1109/vetec.1995.504861

Cited by 35 publications

(16 citation statements)

References 4 publications

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“…The fact that these issues are less constraining in current land mobile radio systems, coupled with the need for spectrally efficient communication, has revived interest in adaptive modulation methods. The main idea behind these schemes is real-time balancing of the link budget through adaptive variation of the transmitted power level [10], symbol rate [11], constellation size [13]- [15], coding rate/scheme [16], or any combination of these parameters [12], [17]- [22]. Thus, without sacrificing BER these schemes provide a much higher average spectral efficiency by taking advantage of the "timevarying" nature of the wireless channel: transmitting at high speeds under favorable channel conditions and responding to channel degradation through a smooth reduction of their data throughput.…”

Section: A Spectral Efficiency Over Fading Channelsmentioning

confidence: 99%

Capacity of Rayleigh fading channels under different adaptive transmission and diversity-combining techniques

Alouini

Goldsmith

1999

IEEE Trans. Veh. Technol.

865

543

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Abstract-We study the Shannon capacity of adaptive transmission techniques in conjunction with diversity combining. This capacity provides an upper bound on spectral efficiency using these techniques. We obtain closed-form solutions for the Rayleigh fading channel capacity under three adaptive policies: optimal power and rate adaptation, constant power with optimal rate adaptation, and channel inversion with fixed rate. Optimal power and rate adaptation yields a small increase in capacity over just rate adaptation, and this increase diminishes as the average received carrier-to-noise ratio (CNR) or the number of diversity branches increases. Channel inversion suffers the largest capacity penalty relative to the optimal technique, however, the penalty diminishes with increased diversity. Although diversity yields large capacity gains for all the techniques, the gain is most pronounced with channel inversion. For example, the capacity using channel inversion with two-branch diversity exceeds that of a single-branch system using optimal rate and power adaptation. Since channel inversion is the least complex scheme to implement, there is a tradeoff between complexity and capacity for the various adaptation methods and diversity-combining techniques.

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Section: A Spectral Efficiency Over Fading Channelsmentioning

confidence: 99%

Capacity of Rayleigh fading channels under different adaptive transmission and diversity-combining techniques

Alouini

Goldsmith

1999

IEEE Trans. Veh. Technol.

865

543

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“…Proposed techniques for adaptive modulation maintain this constant distance through adaptive variation of the transmitted power level [9], symbol time [10], constellation size [4], [5], or any combination of these parameters [2], [3], [6]. The modulation segment of Fig.…”

Section: Coset Codes With Adaptive Modulationmentioning

confidence: 99%

“…Thus for trellis-coded adaptive MQAM we use the power adaptation policy [2, eq. (29)] with power reduced by (5) where . Note that equals the effective coding gain of the trellis code, which is based on the code's fundamental coding gain and its error coefficient [8].…”

Section: Trellis-coded Adaptive Mqammentioning

confidence: 99%

Adaptive coded modulation for fading channels

Goldsmith

Chua²

1998

IEEE Trans. Commun.

746

331

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Abstract-We apply coset codes to adaptive modulation in fading channels. Adaptive modulation is a powerful technique to improve the energy efficiency and increase the data rate over a fading channel. Coset codes are a natural choice to use with adaptive modulation since the channel coding and modulation designs are separable. Therefore, trellis and lattice codes designed for additive white Gaussian noise (AWGN) channels can be superimposed on adaptive modulation for fading channels, with the same approximate coding gains. We first describe the methodology for combining coset codes with a general class of adaptive modulation techniques. We then apply this methodology to a spectrally efficient adaptive M-ary quadrature amplitude modulation (MQAM) to obtain trellis-coded adaptive MQAM. We present analytical and simulation results for this design which show an effective coding gain of 3 dB relative to uncoded adaptive MQAM for a simple four-state trellis code, and an effective 3.6-dB coding gain for an eight-state trellis code. More complex trellis codes are shown to achieve higher gains. We also compare the performance of trellis-coded adaptive MQAM to that of coded modulation with built-in time diversity and fixed-rate modulation. The adaptive method exhibits a power savings of up to 20 dB.

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“…Their work spawned further research in recent years [87]- [95] worldwide. Specifically, Goldsmith and her team [82], [85] at Stanford University, Pearce et al [90] at York University, Kamio et al at the University of Osaka and the Ministry of Post in Japan [86]- [89] contributed further to this field.…”

Section: B Multimode Video Transceiversmentioning

confidence: 99%

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

2000

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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

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Performance of modulation-level-controlled adaptive-modulation under limited transmission delay time for land mobile communications

Cited by 35 publications

References 4 publications

Capacity of Rayleigh fading channels under different adaptive transmission and diversity-combining techniques

Capacity of Rayleigh fading channels under different adaptive transmission and diversity-combining techniques

Adaptive coded modulation for fading channels

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

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