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We propose a simple protocol which allows two legitimate parties to exchange some confidential message over a wireless channel with some chosen level of semantic security against passive eavesdroppers, and without needing either secret or public keys. The proposed method leverages the noisy and fading nature of the channel and exploits coding and all-or-nothing transforms to achieve the desired level...
Multiple Accesses Broadcasting (MABC) is a spectral efficient protocol in two-way relay channel (TWRC). The drawback of this protocol in decode-and-forward (DF) mode is decoding complexity at the relay's side. Erroneous decoding at the relay can bring about error propagation that leads to performance degradation in all of the relay networks operating in the DF mode. In this paper, we propose ML detection...
In this paper, we propose a capacity-approaching analog fountain code (AFC) for wireless channels. In AFC, the number of generated coded symbols is potentially limitless. In contrast to the conventional binary rateless codes, each coded symbol in AFC is a real-valued symbol, generated as a weighted sum of d randomly selected information bits, where d and the weight coefficients are randomly selected...
In underwater acoustic sensor networks, the solution to augment sensor nodes' life time is crucial due to the difficulties in retrieving discharged sensor nodes. Thus, many energy efficient MAC protocols have employed mainly logical ways, such as sleep mode, hand-shaking signaling between nodes, and scheduling of transmission time, rarely using the physical characteristics of underwater acoustic channels...
Feedback of channel state information (CSI) in wireless systems is essential in order to exploit multi-user diversity and achieve the highest possible performance. When each spatially distributed user in the wireless system is assumed to have i.i.d. scalar CSI values, the optimal fixed-rate and entropy-constrained point density functions are established in the high-resolution regime for the quantization...
The work is related to the use of error correction coding and adaptive equalization as an aid to Maximal Ratio Combining (MRC) in order to improve bit error rate(BER)s of received signals in wireless channels with fading characteristics. Several modulation schemes are used in the transmission in Gaussian, multipath Rayleigh and Rician fading channels. The work adopts a few error correction codes and...
We consider the performance of small-scale heterogeneous cooperative networks in which some nodes can transmit and/or receive using channels not available to other nodes, i.e., multimodal communication networks. As an example, we assume the presence of an additional wired channel in a conventional diamond relay network operating under the Laneman protocol, and we find analytical expressions for outage...
In this paper, a new two-step spectrum sensing scheme based on energy detection and maximum eigenvalue detection is proposed for cognitive radio. When the wideband frequency range is divided into multiple sub-channels, energy detection is firstly used for coarse sensing in each sub-channel to determine the existence of the primary user. As no primary user is decided, maximum eigenvalue detection is...
The strict avalanche criterion (SAC) is a desirable property of traditional symmetric-key cryptographic algorithms. The SAC is said to be satisfied if, whenever a single input bit is complemented, each of the output bits changes with a probability of one half. In terms of the block ciphers context, such a small change in either the key or the plaintext should cause a drastic change in the ciphertext...
Streaming degradable content (such as video or audio) over a wireless channel presents new challenges to modern digital design, which was founded on the separation theorem of Shannon theory. Joint source-channel coding (JSCC) has recently received increasing interest to address the varying nature of the wireless channel conditions (under mobility or multicast). The conventional approach to JSCC which...
Deterministic network calculus (DNC) is not suitable for deriving performance guarantees for wireless networks due to their inherently random behaviors. In this paper, we develop a method for Quality of Service (QoS) analysis of wireless channels subject to Rayleigh fading based on stochastic network calculus. We provide closed-form stochastic service curve for the Rayleigh fading channel. With this...
Geographic routing is a scalable routing scheme for wireless networks, where nodes make local routing decisions using position information. Cooperative transmissions utilize spatial diversity to combat fading in wireless channels. In this paper, we incorporate cooperative transmissions into geographic routing, and propose the Location-Aware Cooperative Routing (LACR). In LACR, a node that receives...
We propose two scheduling protocols which are applicable to two-hop relay networks based on mobile WiMAX system: the first protocol adopts a persistent scheduling (PS) scheme in both hops, called the PS-PS protocol, while the second protocol adopts the PS scheme only in the first hop and the dynamic scheduling (DS) scheme in the second hop, called the PS-DS protocol. We optimize the above two protocols...
Channel reciprocity is regarded as one of the most important advantages of TDD systems. However, the RF front-ends contribute to the channel experienced, and their TX/RX mismatches might cause reciprocity error, and thus degrade system throughput. Therefore, channel reciprocity calibration is a crucial issue. Among the existing calibration methods, Over-the-air (OTA) calibration is a promising approach...
In this paper we consider a single cognitive radio seeking a transmission opportunity by sequentially sensing a number of statistically independent primary channels. We study the joint optimization of the time spent to sense a channel, the decision threshold to determine whether the channel is free or busy, together with the order with which the channels are sensed. The sensing time and decision threshold...
Cooperation among nodes in a network provides spatial diversity as well as it enhances the system's overall capacity and coverage. However the benefits provided by such systems depends on the level of cooperation (based on the relay information quality) and on the coordination among nodes. One way of achieving proper coordination is through the use of feedback channels. An implicit feedback channel...
In this paper, a new feedback scheme is proposed for downlink OFDMA system with frequency domain packet scheduling to achieve multiuser diversity. Recent work showed that the multiuser diversity can be gained by using the so-called average best-M feedback scheme where bit-mask indicating the identification of best M subcarriers together with the average channel quality indicator of those subcarriers...
Many radio applications require a Signal-to-Noise Ratio (SNR) Enhancer to combat the radio channel impairments. In this paper, we are particularly interested in combating the radio channel impairments resulted from long-term and short-term channel variations. The SNR Enhancer pre-conditions the received signal strength (RSS) of the signal such that the SNR of the signal is increased; hence the system...
Transmission power control can significantly improve energy-efficiency of wireless sensor network communications. Power consumption models are typically based on dependence of channel attenuation on distance. However, in practice, information on distance is usually not available and the dependence of channel attenuation on distance is not sufficiently accurate. Therefore, we propose more accurate...
Recently, multipath in wireless channels has shown an interesting aspect. It has been found that wireless channels may provide a common reciprocal source of randomness for any two communicating nodes. This seems particularly interesting for secret key generation in wireless networks. In this paper, we consider the randomness property of wireless channels and present an intelligent algorithm for key...
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