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In this paper, we investigate the capacity of wireless hybrid networks, in which a wired network of base stations is used to support long-range communications between wireless nodes. We introduce the multiple access technique by allowing more than one source node to transmit simultaneously and utilizing successive interference cancellation to decode information at the destination node. Our results...
Femtocells promise to increase the number of users served in a given macrocell by creating indoor hotspots connected to the mobile operator network via cheap backhaul links (i.e., the Internet). However, the interference created by the femtocell transmissions may critically impair the performance of the macrocell users. This effect can be potentially alleviated via so called open-access home base...
We consider three-user multiple access cognitive radio channels and obtain achievable rates for reliable communication over these channels. A synopsis of the channel model is as follows: before establishing communication with the receiver, one of the transmitters (named primary) splits its message-set into two parts and shares them among the remaining two transmitters (named secondary) via a noiseless...
Due to the broadcast nature of wireless channels, the two-way system can be eavesdropped on when a confidential message is transmitted, which is one of the motivations of this paper. While most of existing work focuses on the discussion of secrecy rate with information theoretical approach, this paper discusses the probability of successful detection for the system experiencing exponential path loss...
The use of hybrid automatic-repeat-request (HARQ) with multi-antenna systems (MIMO) promises high throughput with high reliability in broadband wireless communication systems. One of the combining methods in MIMO-HARQ is by directly optimizing the log-likelihood ratio (LLR) values instead of compensating the multiple signal-to-interference-and noise power ratios (SINRs) as in conventional combining...
This paper investigates the application of lossy distributed source coding to high resolution multispectral images. The choice of distributed source coding is motivated by the need for very low encoding complexity on space and airborne platforms. The data consists of red, blue, green and infra-red channels and is compressed in an asymmetric Wyner-Ziv setting. One image channel is compressed using...
The declining channel quality by chance would bring about the rise of error rate in wireless transmission. Moreover, automatic repeat request mechanisms would give rise to the tremendous increasement of transmission delay. Therefore, research on the scheme of low transmission delay is of great importance. In this paper, we propose the novel decoding algorithm to obtain a tradeoff between Belief Propagation...
Receive beamfoming techniques play an important role in MIMO communications systems as means to mitigate interference and enhance the link quality. Multipoint receive beamforming methods are expected to provide additional gains in systems employing advanced coordinated multipoint processing. Due to its importance, receive beamforming has been studied extensively in the literature. The optimal detection...
We consider a wireless network in which a source terminal communicates with a destination and a relay terminal is occasionally present in close proximity to the source without source's awareness, suggesting oblivious protocols. We incorporate a two-layer broadcast approach into two cooperative strategies based on the decode-and-forward scheme - Sequential Decoded-and Forward (SDF) and the Block-Markov...
Wireless Sensor Networks (WSNs) consist of a set of small devices with limited energy resources, reduced processing capabilities and a radio frequency communication unit with limited transmission power. Transmission over the wireless channels is prone to noise and interference which causes the reception of erroneous packets at the receiving node. Automatic Repeat Request (ARQ) techniques are usually...
This paper describes the overall design framework of the monitoring for radio control signaling on Iub interface. Because of the complexity of the Iub interface protocol stack, the protocol configuration parameters acquisition solution of radio control signaling based on AAL2 which mainly used Hash indexing techniques is proposed. The intelligent inference module generates the protocol parameters...
The capacity of a class of multi-way relay channels, where L users communicate via a relay (at possibly different rates), is derived for the case where the channel outputs are modular sums of the channel inputs and the receiver noise. The cut-set upper bound to the capacity is shown to be achievable. More specifically, the capacity is achieved using (i) rate splitting, (ii) functional-decode-forward,...
This paper presents a new approach for digital image watermarking and for transmission of watermarked images over bursty wireless channels. In this approach, biorthogonal wavelet transform based method is proposed for digital image watermarking and turbocoded JPEG2000 is proposed for correction of transmission errors due to the bursty wireless channels. The proposed approach is corroborated with implementation...
A new theory, known as Compressive Sensing (CS), has recently proved that sparse or compressible signal can be accurately reconstructed from very highly undersampled data by solving by solving a convex LI optimization problem. This paper, based on such new theory, presents a novel multiple description coding (MDC) method to combat packet loss. According to compressive sensing framework, our method...
This paper proposes a joint JPEG-block coding system (JJBC) based on BCJR decoding with expurgating trellis that maintains an acceptable image quality over AWGN and wireless channels. The joint design of JPEG compression and block codes in the transmitter has the advantage of avoiding error propagation and of low decoding complexity over the conventional tandem system with separate optimization of...
Frequency diversity is a proved remedy against the detrimental impact of the frequency selectivity of radio channels. In the case of the channel access scheme OFDM, the obvious and known approach to frequency diversity would consist in commonly spreading the data elements to be transmitted over all OFDM subcarriers. Unfortunately, this approach of full data spreading would render optimum, that is...
In this paper we consider a cognitive interference channel with two confidential messages. In our scenario, although the cognitive transmitter cooperates with the primary sender, the primary and cognitive messages must be secure at unintended receivers. The level of secrecy is measured by the equivocation rate. Also an expression is obtained for the rate-equivocation region of the discrete memoryless...
This paper considers certain aspects of some well-known multiple-input single-output (MISO) codes. In the first section it is proved how in some special cases the n + 1 MISO channel can be seen as consisting of several parallel MISO channels having less transmit antennas. It is also pointed out that unitary conjugation does not change the diversity-multiplexing tradeoff (DMT) of a code. These simple...
Multiple-input double-output (MIDO) codes are important in future wireless communications, where the portable end-user device is physically small and will typically contain maximum two receive antennas. Especially tempting is the 4×2 channel, where the four transmitters can either be all at one station, or separated between two different stations. Such channels optimally employ rate-two space-time...
In this paper, we develop a novel approach for joint channel estimation and Markov Chain Monte Carlo (MCMC) detection for time-varying frequency-selective channels. First, we propose a sequential channel estimation (SCE) MCMC algorithm that combines an MCMC algorithm for data detection, and an adaptive least mean square (LMS) algorithm for channel tracking, in a sequential fashion. Then we develop...
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