Scalable Modulation for Scalable Wireless Videocast

IEEE J. Select. Areas Commun.

et al. 2012

Self Cite

Abstract-User cooperation in wireless networks is inherently a cross-layer optimization problem. We identify a new direction for cooperative communications: i.e., in addition to the pointto-point communication channel between the transmitter and the receiver, the communication configuration should take the network topology into account. In this paper, we first propose a network modulation (NM) design that can transmit bits with different SNR requirements in a single symbol transmission. We then propose an error-correction coding assisted relay (EAR) scheme that is also configured according to the network topology. We study the performance of NM and EAR in both a threenode collinear network and a two-dimensional cellular network. Extensive simulations have been conducted, which demonstrate the substantial performance gain of the proposed schemes, in terms of both a higher network throughput and a lower bitenergy consumption. Comparing between NM and EAR, NM is more beneficial for the downlink performance and EAR is more beneficial for the uplink performance. Combining NM and EAR leads to a more efficient cooperative network. It is concluded that the topology-aware physical layer design will be a promising direction with many open issues for further study.

Section: Related Workmentioning

confidence: 99%

“…At the receiver side, we first define the decision regions for L1 and L2 symbols, and then demodulate each symbol to L1 and L2 bits directly. This strategy requires a minor modification to a QAM demodulator (for other options, see [10]). …”

Section: E Implementationmentioning

confidence: 99%

Topology-Aware Modulation and Error-Correction Coding for Cooperative Networks

Yang

Cai

IEEE J. Select. Areas Commun.

et al. 2012

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“…In [10], we designed a scalable modulation (s-mod) scheme which uses software to remap the constellations of typical QAM schemes to provide DiffServ for video multicast over wireless networks. Performance study shows that the software based solution, s-mod, can achieve performance similar to or even better than SPC (or h-mod) for supporting video multicast in dynamic wireless environment.…”

Section: Related Workmentioning

confidence: 99%

“…Different from the work in [10], [11], here, we focus on how the software based modulation remapping can be combined with the link layer resource allocation and network layer relay and routing to significantly improve the throughput of wireless networks, for any types of applications (with or without DiffServ requirements), anycast services, and singlehop or multi-hop wireless networks.…”

Section: Related Workmentioning

confidence: 99%

Network modulation: A new dimension to enhance wireless network performance

Yang

2011 Proceedings IEEE INFOCOM

Cai

2011

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Abstract-We introduce an approach called network modulation which gives us a new dimension to improve wireless network throughput and save energy. In current wireless systems, when a source transmits data to the receiver through a single-hop or multi-hop wireless path, the physical layer modulates and demodulates the information bits hop-by-hop, and the transmission over each hop is treated the same as in a point-to-point communication link. Given the broadcast nature of wireless medium and the wide variation of wireless channel quality, we let a sender transmit messages to multiple receivers simultaneously, using a software mapping technology, called network modulation, to redefine the constellation of typical quadrature amplitude modulation (QAM) schemes. As the software-based network modulation schemes do not require specialized communication hardware, they can be implemented with low cost and high flexibility. Network modulation can be used to improve network performance in a wide range of scenarios, for anycast (broadcast, multicast and unicast) services, one-way or two-way traffic, and single-hop or multi-hop wireless paths, in infrastructure or ad hoc networks. The minimum requirement for applying network modulation is that there are no less than three nodes within each others' transmission ranges, so we can consider modulation, topology control, resource allocation, and routing jointly.

“…In this paper, we propose a new time/locationcritical (TLC) framework for EM dissemination and use the scalable modulation and coding (SMC) scheme proposed by us in [9] to achieve the goal. By redefining the bit-to-symbol mapping in the modulation constellation, SMC allows us to encode information of different importance at the same time.…”

Section: Introductionmentioning

confidence: 99%

Time and Location-Critical Emergency Message Dissemination for Vehicular Ad-Hoc Networks

Zhuang

Pan

IEEE J. Select. Areas Commun.

et al. 2011

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Abstract-One promise of Vehicular Ad-hoc Networks (VANET) is to considerably increase road safety and travel comfort by enabling inter-vehicle communications. Among a vast array of potential applications, emergency message (EM) dissemination has attracted a lot of attention in the literature. In this paper, we propose a time/location-critical (TLC) framework for EM dissemination and use our scalable modulation and coding (SMC) scheme to achieve the goal. In specific, vehicles near the accident site (or the point-of-interest location) receive guaranteed, detailed messages to take proper reaction immediately (e.g., slow down or change lanes), and vehicles further away have a high probability to be informed and make location-aware decisions accordingly (e.g., detour or reroute), with the assistance of reverse traffic when possible and necessary. The efficacy of the proposed framework is analyzed and validated by extensive numerical and simulation results. The TLC framework and the use of the SMC scheme are shown to be able to disseminate EMs effectively and efficiently by taking both the time and location criticality into account, while simplifying the design of radio transceivers and media access control protocols for VANET.Index Terms-Vehicular ad-hoc networks, emergency message dissemination, scalable modulation and coding