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A sparse multipath channel is characterized by a small number of randomly distributed scatterers. This study proposes a methodology for the modelling of sparse multipath channels. The new methodology is then used to develop a sparse narrowband multipath channel model by applying the sum-of-cisoids (SOC) principle. The statistical properties of the presented sparse SOC multipath channel model are studied...
This paper investigates the characteristics of the complex received signal in body area networks for two environments at the opposite ends of the multipath spectrum at 2.45 GHz. Important attributes of the complex channel such as the Gaussianity of the quadrature components and power imbalance, which form the basis of many popular fading models, are investigated. It is found that in anechoic environments...
In this paper, we propose a novel multilevel coded linear physical-layer network coding scheme with extended mapping (LPNC-EM) for Rayleigh fading two-way relay channels (TWRC). The relay node adaptively selects the linear generator matrix and directly maps the superimposed signal of the two users into the linear network coded combination over the hybrid Galois Field (GF(22) or GF(23)). The selection...
This paper proposes a three-dimensional (3-D) three-concentric-cylinders model for multiple-input-multiple-output (MIMO) mobile-to-mobile (M-to-M) relay fading channels in amplify-and-forward (AF) communication networks. Based on this model, a parametric reference model for wideband MIMO M-to-M relay fading channels in urban macrocells is developed. From the reference model, the space-time-frequency...
In this paper, we propose a buffer-aided relaying protocol for a multiuser relay network consisting of N sources, a relay with a buffer, and a destination. All nodes are equipped with a single antenna and operated in a decode-and-forward half-duplex mode. We assume the direct source-destination links do not exist. Different from the conventional multiuser relaying that the half-duplex relay always...
We consider a decode-and-forward based wireless multihop network with a single source node, a single destination node, and N intermediate nodes. To increase the spectral efficiency and energy efficiency of the system, we propose a cooperative multihop communication with spatial reuse, in which interference is treated as noise. The performance of spatial-reused space-time coded cooperative multihop...
We study the problem of interference management for device-to-device (D2D) communications where multiple D2D users may coexist with one cellular user. The problem is to optimize the transmit power levels of D2D users to maximize the cell throughput while preserving the signal-to-noise-plus-interference ratio (SINR) performance for the cellular user. This is the so-called multi rate power control problem...
This paper considers relay positioning in wireless butterfly networks consisting of two source nodes, a relay node and two destination nodes. The relay-assisted data transmission from two source nodes to two destination nodes is carried out based on either physical-layer network coding (PLNC) or analog network coding (ANC) techniques. The reliability of communications in wireless network-coded butterfly...
Heterogeneous wireless systems such as a combination of mobile broadband wireless access (MBWA) and wireless local area network (WLAN) are candidates to attain higher throughput and wide coverage in the next generation mobile communication systems. A multimode receiver to demodulate signals with multiple air interfaces is required in the heterogeneous systems. In this paper, we discuss an implementation...
We investigated the secrecy outage of unicast channels in random networks exposed to unknown numbers of randomly located eavesdroppers, obtaining original expressions which include uncertainty in terms of the location of legitimate nodes relative to eavesdroppers, the number of eavesdroppers, and fading. Under such conditions, we derive the path gain distributions of legitimate and eavesdropper nodes,...
In this paper, a novel transmit antenna selection scheme for multiple input multiple output (MIMO) wiretap channels is proposed. This new scheme achieves higher secrecy performance by exploiting eavesdropper's channel state information. The key idea behind our proposal is to perform the antenna selection aiming to maximize the overall secrecy rate instead of maximizing the instantaneous signal-to-noise...
Multiple access communication techniques have direct impact on bandwidth and power efficiencies for future wireless networks. In this paper, a new multiple access scheme combining both adaptive modulation and multiple access coding is proposed to provide an efficient and robust method of combining signals from multiple users over fading channels. Hybrid Multiple Access Coding with Adaptive Modulation...
Cognitive Radio (CR) is proposed to maximize spectrum utilization. When the licensed user is not using the spectrum, CR will then use it to communicate among each other. Hence, spectrum sensing, a procedure to observe primary user's existence, is important to CR. In this paper, we investigate the energy detection based cooperative spectrum sensing technique as it offers low complexity and significantly...
In this work, we investigate the performance of cognitive multihop regenerative relaying systems in the “underlay” spectrum sharing scenario. The multiple relays perform “detect-and-forward” relaying strategy to convey a message with an order m quadrature amplitude modulation (m-QAM) from the source to the destination over independent but not necessarily identical Nakagami-m fading channels. We adopt...
In this paper, coding techniques for the multiple-input multiple-output multi-hop amplify-and-forward (MIMO-MH-AF) quasi-static fading channel with perfect feedback are proposed. First, the diversity orders that can be achieved over this channel are investigated. The study is based on the partitioning of the channel onto several paths whose individual diversity order add to attain the maximum diversity...
This paper proposes a novel deterministic inter-leaver, called almost linear interleaver (ALI) as the generalization of block and linear interleavers, and discusses its parameter/depth selection for coded orthogonal frequency division multiplexing (COFDM) system over Rayleigh fading channel. The concept of diversity guard is introduced to guarantee the achievable maximum diversity order with a reasonable...
This paper studies the four-node Multiple Access Relay Channel (MARC) under quasi-static block Rayleigh fading channels and Gaussian noise environment. A relay employs Demodulate-and-Forward (DMF) protocol in order to help two channel-encoded sources to communicate with a destination. The contributions of the paper are threefold: i) we propose a Near Optimal Joint Network/Channel decoding (NO-JNCD)...
In this paper, we investigated the cooperative sensing in a heterogeneous cognitive radio (CR) network scenario, where each secondary user (SU) may be equipped with different number of receive antennas and have different signal processing capacity, e.g., sampling rate. By considering the discrepancy in sensing reliability of different SUs, we extended the existing researches to propose an optimal...
In this paper, we analyze the performance of an energy detector operating over Gamma shadowed Rice fading channels, namely Rice fading channels with the fluctuating line-of-sight components following the Gamma distribution. This composite multi-path/shadowing model has been shown to provide remarkably accurate fading characterization while leading to closed-form expressions for important channel statistics...
This paper proposes the theoretical derivation method of both the frequency spectrum and the bit error rate (BER) performance for uplink Orthogonal Frequency Division Multiple Access (OFDMA) in the presence of the nonlinear distortion. Since OFDMA has two different subcarrier allocation methods such as localized FDMA (LFDMA) and interleaved FDMA (IFDMA), there is the difference, in terms of the influence...
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