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This paper demonstrates that growth codes, based on Raptor channel coding, allow incremental protection of H.264 video codec data-partitioned network adaption layer units. When combined with increased protection of video reference frames, in an ADSL erasure channel up to 10 dB in video quality (PSNR) can be gained through this scheme compared to equal error protection with rateless codes. Equivalent...
In this paper, we present an unequal power allocation method that exploits the hierarchical structure of JPEG2000 coded bitstream, along with the channel state information, to assign different transmission powers to different parts of the bitstream at the coding pass level. Based on the information from the JPEG2000 bitstream, we first develop a distortion model to evaluate the distortion of the reconstructed...
Network coding has been widely recognized as a promising information dissemination approach for wireless networks. However, in practical wireless networks enabled with network coding, different peer sending sequences make significant impact on overall network throughput and transmission delay. In this paper, we study the peer scheduling problem, which is defined as how to intelligently schedule the...
To overcome the adverse effects of wireless channel, cooperative communications is the practical implementation of Multiple-Input-Multiple-Output (MIMO) concept in size constraint nodes. To exploit the benefits of cooperative transmission properly, we use the block-Markov encoding. Recently, an operational implementation of this information theoretic coding strategy, using network coding, has been...
In this work, a novel two-level rate superposition coding relaying (SC-relaying) strategy is investigated. In this SC-relaying strategy, the channel state feedback of relay-to-source is introduced under a long term power constraint at source. For the SC-relaying strategy, the source power SNR exponent constraints are first obtained. And then, by using the power SNR exponent constraints, the optimizing...
We consider a multiple path wireless network and address the problem of coding and routing a message in a manner that guarantees both robustness and security. Each path in the network is assumed to be a wiretap channel that includes both a main channel and a wiretap monitored by an eavesdropper. We then show that Raptor codes can be used to achieve both perfect secrecy and zero error probability....
Because of restricted mobility patterns, multi-hop routing, and wireless channel conditions, streaming video over a vehicular ad hoc network (VANET) is a daunting task. This paper demonstrates that H.264 codec flexible macroblock ordering (FMO) with receiver error concealment is capable of streaming good-quality video across a VANET. FMO is shown to be superior to other error resilience techniques...
In this paper we consider a server sending a scalable video stream over a wireless channel to an end-user. We design a fast rate adaptation algorithm which chooses the right transmission policy (video data and associated unequal error protection) based on channel feedback. Our algorithm can be easily implemented as a smart scheduling module at the server side, which adapts its packet selection rules...
The availability of inexpensive CMOS cameras and microphones that can ubiquitously capture multimedia content from the environment is fostering the development of Wireless Multimedia Sensor Networks (WMSNs), i.e., distributed systems of wirelessly networked devices that can retrieve video and audio streams, still images, and scalar sensor data. WMSNs require the sensor network paradigm to be re-thought...
We consider the two message set problem, where a source broadcasts a common message W1 to an arbitrary set of receivers U and a private message W2 to a subset of the receivers P ?? U. Transmissions occur over linear deterministic channels. For the case where at most two receivers do not require the private message, we give an exact characterization of the capacity region, where achievability is through...
In wireless OFDM-based systems, coding jointly over all the sub-carriers simultaneously performs better than coding separately per sub-carrier. However, the joint coding is not always optimal. In this paper, we propose a novel coding scheme based on fountain codes, which combines the separate coding and the joint coding over all the sub-carriers. The key element in the new proposed system is that...
We examine the extent to which Gaussian relay networks can be approximated by deterministic networks, and present two results, one negative and one positive. The gap between the capacities of a Gaussian relay network and a corresponding linear deterministic network can be unbounded. The key reasons are that the linear deterministic model fails to capture the phase of received signals, and there is...
The compound wiretap channel generalizes the classical problem in broadcast information-theoretic secrecy by allowing a class of potential eavesdroppers. This represents uncertainty in the eavesdropper channel and the characterization of its secrecy capacity is an open question. In this paper we present a new coding scheme that generalizes known approaches to this problem. The scheme prefixes an artificial...
In this paper, we propose a novel generalized approach to estimate the time-probabilistic characteristics of the cryptographic protocols by means of random graphs. The influence of channel errors on the performance of authentication and encryption protocols is also studied. Our results demonstrate that the usage of cryptographic algorithms influences the throughput in many ways.
In this paper, we focus on multi-user MIMO broadcast channels with few users feeding back their channel estimates, i.e. K linear in the number M of transmitting antennas. Under this condition, the chance of finding a subset of users almost orthogonal vanishes when M gets large. For this reason, we show that the zero forcing (ZF) beamformer, commonly accepted for practical implementations, can be easily...
In this paper we propose a partial network coding with cooperation (PNC-COOP) scheme that mitigates error propagation due to channel imperfections and achieves acceptable throughput in wireless ad hoc networks. It combines opportunistic network coding with decode-and-forward cooperative diversity. The proposed PNC-COOP is a decentralized strategy which provides substantial benefits when transmission...
A scalable video delivery transmission framework over MIMO OFDM wireless channels by combining power allocation and antenna selection scheme has been proposed. The framework consisting of independently decodable layers (3D ESCOT), UEP channel coding structure, and antenna selection scheme provide more system error resilience even during deep fading period in wireless channels. A new algorithm is proposed...
If binary signaling is used in an n-channel OFDM link, the maximum possible bit rate is n bits per OFDM symbol duration. We show a simple scheme based on selective channel use that increases this capacity by nearly 60%. By using only k channels out of the n, we show how to use the choice of the k channels as an additional auxiliary channel. For proper choice of parameters, the information transferred...
Carrier sense multiple access (CSMA) is the conventional medium access method used in wireless ad hoc networks. it can be enhanced as a space-division based CSMA (namely, SD-CSMA) by using multi-antenna techniques, which allows concurrent link communications in the network. In this paper, we present a MAC design that can adaptively switch between CSMA and SD-CSMA in multi-antenna based ad hoc networks...
Network coding can achieve the maximum possible rate defined by the max-flow min-cut theorem through encoding of the input streams at the correlative nodes under the ideal channel condition. When error happens, encoding will bring in error propagation. By introducing redundancies in space domain, network error correction is proposed, however, with the high encoding and decoding complexity. Specifically,...
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