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Adaptive radio resource management policy aware of the demand for wireless services is termed dynamic spectrum access (DSA). In order to evaluate the effectiveness of DSA, dynamics of the demand should be considered. In the present paper, dynamics of the spectrum market, which is a way to realize DSA, are evaluated from the economic perspective. Modeling the spectrum market system by using game theory,...
In order to avoid the resource inefficiency of all-participated cooperation in wireless amplify-and-forward relay networks, a novel relay selection scheme based on the channel gain of the source-relay and relay-destination links is proposed. A condition is introduced to maximize the upper bound of the overall received signal-to-noise ratio (SNR). The relay nodes which have bad channel conditions are...
The purpose of this paper is to reduce the complexity of scheduling scheme for OFDMA/SDMA system with multimedia traffic. To achieve this purpose, we propose a low-complexity beamforming-based scheduling (LCBS) scheme to solve the multi-dimensional (space, time, and frequency) radio resource allocation problem in OFDMA/SDMA systems. By utilizing a semi-orthogonal user selection (SUS) algorithm, the...
In this paper, we consider the optimal rate and power allocation that maximizes a general utility function of average user rates in a fading multiple-access or broadcast channel. By exploiting the greedy structure of the capacity-achieving resource allocation for both multiple-access and broadcast channels, it is established that utility-maximizing allocation policy can be obtained through dual-based...
In this paper, we address the incentive-based relay-selection problem over multi-source and multi-relay wireless networks. A two-side market game approach is employed to jointly consider the benefits of all sources and relays. The equilibrium concept in such games is called core. The outcomes in the core of the game cannot be improved upon by any subset of players. These outcomes correspond exactly...
This paper presents a low complexity receiver for downlink orthogonal frequency division multiple access (OFDMA) systems. We consider the comb-type subcarriers assignment for a resource block. Based on this arrangement, a resource block could be demultiplexed at the user equipment without performing fast Fourier transform(FFT) on one OFDMA symbol. The inter-symbol interference(ISI) resulted from multipath...
This paper considers a cognitive radio network where a secondary user shares the same narrow band with a primary user for transmission. Instead of adopting the conventional interference-power/interference-temperature constraint, this paper proposes a new type of constraint for the secondary user to protect the primary transmission, which limits the maximum outage probability of the primary transmission...
In this paper, we derive optimal pilot power allocation for OFDM systems suffering from in-phase and quadrature-phase (IQ) imbalances. Existing works in literature on IQ imbalances optimize for pilot spacings and pilot designs. However, in all these works, optimal power allocation between pilot and data symbols has not been considered. Using a lower bound on the average channel capacity as a metric,...
The problem of resource allocation (RA) in a downlink OFDMA system with minimum user rate requests is examined under the realistic scenario of partial (imperfect) channel state information (CSI) at the base station. The challenge in this setting is the non-zero probability of outage events which may lead to significant performance degradation if algorithms assuming perfect CSI are utilized. In this...
A cross layer Unequal Error Protection (UEP) scheme based upon the multimedia position-value (P-V) partitioning has been recently proposed to only improve energy-distortion performance in Wireless Multimedia Sensor Networks (WMSN). There is also a great potential to adapt this UEP scheme into multimedia stream integrity protection. However, performance gains in multimedia transmissions with considerations...
With the advent of new applications, one of the primary applications supported in downlink cellular systems is streaming video. QoS for streaming video entails data transmission to the mobile stations with limited latency and limited jitter. This requirement on latency and jitter can be mapped to the number of yet-to-be-played packets in a mobile station's buffer, to always be above a certain minimum...
In this paper, we develop a rate allocation scheme for interleave-division multiple-access (IDMA) systems with iterative decoding. We use a fully-analytical approach to predict the performance of the scheme and propose a modified linear programming method to design the rate profile. Numerical results show that with just repetition coding and rate allocation, the performance of the scheme is only about...
In this paper, we consider the energy-efficient resource allocation that minimizes a general cost function of average user powers in wireless networks. A class of so-called ??-fair cost functions is derived to balance the tradeoff between efficiency and fairness in energy-efficient designs. With these novel cost functions, optimal resource allocation schemes are developed for fading time-division...
In this work we consider the optimization of the power assigned to the user streams, in a coordinated base station downlink environment, when zero-forcing is employed to remove interference among users. Two schemes based on the waterfilling technique are proposed and compared to the optimal solution, which can be obtained numerically, by using convex optimization. We show that the proposed schemes...
In this paper, we investigate the asymptotic e-outage capacity of a half-duplex large fading relay network, which consists of one source node, one destination node, and N relay nodes. The relay nodes are assumed to be randomly deployed in a given area and under fatal independent random attacks with probability p. With a total power constraint on all the nodes, we examine the e-outage rate of the amplify-and-forward...
Cognitive radio technologies have become a promising approach to increase the efficiency of spectrum utilization. Although cognitive radio has been intensively studied in recent years, only a few works have discussed security aspects. In this paper, we focus on the jamming attack, one of major threats to cognitive radio networks, where a malicious user wants to jam the communications of secondary...
In this paper, we study the joint power allocation and relay selection problem for multi-user amplify-and-forward (AF) cooperative networks. To increase the system's spectral efficiency under the orthogonal transmission assumption, each source-destination pair is constrained to be assisted by a small subset of a set of available relays. The aim of this work is to establish a framework that determines...
An important issue of supporting multi-user video streaming over wireless networks is how to optimize the systematic scheduling by intelligently utilizing the available network resources while, at the same time, to meet each video's QoS (quality of service) requirement. In this work, we study the problem of video scheduling over multi-channel multi-radio multi-hop networks with the goals of minimizing...
This paper deals with the allocation of resources and the creation of distribution trees for P2P video streaming. Assuming that the video distribution is based on a multiple description codec (MDC), the proposed approach performs jointly the two tasks, in a completely distributed client-based fashion, by means of an evolutionary (socially inspired) game played by all peers. The key idea of the evolutionary...
In this paper, we establish a rate duality between the forward and reverse links of MIMO interference channel, where the reverse links are obtained by exchanging the roles of transmitters and receivers in the forward links, and the corresponding channel matrices are conjugate transpose of the forward channel matrices. Since the capacity region for general interference channel is unknown, we show that...
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