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This paper proposes a BER (bit error rate) analysis framework for proactive relay selection (PRS) in underlay cognitive networks with channel information imperfection (CII), maximum transmit power constraint, interference power constraint, independent non-identical (i.n.i) Rayleigh fading distributions, and arbitrary modulation level. The analysis provides exact and asymptotic BER expressions, which...
This paper studies the blind interference alignment (BIA) of a heterogeneous 3-user 2x1 broadcast channel (BC). In the BC considered, the transmitter equipped with two antennas broadcasts information symbols to three receivers with each possessing a unique reconfigurable antenna. By heterogeneous it means that the three 2x1 links connecting the transmitter and the three receivers experience independent...
In this paper, the performance of interference sensing of full duplex cognitive anti-jamming (FCAJ) receiver impaired by phase noise in local oscillators is investigated under fading channel. Firstly, energy detection based the interference signal to noise ratio (INR) of FCAJ receiver with phase noise under different channels is analyzed. Then, the detection and false alarm probabilities in closed-form...
A key challenge in operating cognitive radios (CRs) in a self-organizing (ad hoc) network is to adaptively and efficiently allocate transmission powers and spectrum among CRs according to the surrounding environment. Cognitive radio networks provide high bandwidth to mobile users via heterogeneous wireless architectures and dynamic spectrum access techniques. CR networks inflict challenges due to...
This paper presents an indoor-to-outdoor signal propagation model based on exhaustive measurements campaign. The conducted measurements considered an indoor transmitter and an outdoor receiver to analyze the interference in future 5G networks with femtocells overlaying macrocells. To propose a practical model, architectural details of the buildings and the exact position of the transmitter, which...
This study focuses on hourly breakdown of received signal strength enhancement events, short-time fading characteristics during and outside enhancement and co-site and co-frequency enhancements on two over-sea, trans-horizon paths. Hourly breakdown of enhancement events reveals a diurnal pattern, with a greater percentage of enhanced signal strengths predominantly occurring during late afternoon/evening...
Massive Multiple-Input Multiple-Output (MIMO) antenna arrays are being studied for 5G due to their ability to focus energy towards desired receiver, reducing interference to other users, giving rise to higher spectral and energy efficiencies. Conventional analysis assumes that the large scale fading component of the channel model is constant across the entire Massive MIMO antenna array. However, when...
MIMO systems provides number of features like spatial diversity, multiplexing gain, and high spectral efficiency gain by keeping the bandwidth expansion or transmission power similar to other systems. The major concern in the system is inter symbol interference (ISI) caused by the channel. An equalizer is deployed on the receiver side to detract the effect of ISI. In this paper, simulation is done...
Two-path cancellation schemes have attracted much attention due to its effectiveness in suppressing intercarrier interference (ICI) in orthogonal frequency division multiplexing (OFDM) systems. In this paper, we derive the exact closed-form expressions of the signal-to-interference-plus-noise ratio for two-path cancellation schemes in multipath fading channels as well as their upper bounds, which...
This research addresses the issue of resource and power allocation in small cell networks, and focuses on two aspects: i) the interference coordination among cells; and ii) the resource allocation among the users served by the same cell. Due to the density of small cells, centralised interference coordination schemes require an enormous level of communication among cells. Fuzzy logic (FL) is a promising...
In recent years, the device-to-device (D2D) proximity services in the long term evolution advanced (LTE-A) system drew much attention and was standardized in LTE Release-12 (R12). Device discovery is a fundamental aspect of D2D proximity services, allowing discovery user to advertise its presence and/or discover others in its neighborhood. In this paper, the main D2D discovery aspects defined in LTE-A...
The throughput of small cell networks (SCNs) is limited by intercell interference. Except numerous techniques of interference coordination, simply caching several popular files at each user provides an alternative approach to reduce interference by pre-offloading. This becomes possible nowadays due to the facts that the cost of memory devices is reducing quickly and content delivery is gradually dominating...
The need for accurate and relevant CSI feedback is one of the pillars for the efficiency of cellular systems. However, one problem facing CSI reporting is the effect of CSI aging such that the reported CSI information is obsolete when data is scheduled based on it. CSI may instead be predicted in order to mitigate some of the aging loss. In doing so two things need to be considered. First, the CSI...
This paper investigates a four-node wiretap network including one source (S), one relay (R), one legitimate receiver (D) and one eavesdropper (E) with cooperative jamming in a two-hop relay transmission. In the first phase, S transmits an useful signal to R while D transmits an interference signal with the purpose of confounding the eavesdropper. In the second phase, R broadcasts the mixture signal...
This paper concerns time synchronization of MIMO systems. The current most powerful receiver is a generalized likelihood ratio test (GLRT) receiver, and assumes unknown, stationary, circular, and spatially colored Gaussian noise. However, this receiver is more complex than its non-GLRT counterparts, which, unfortunately, do not perform as well in most cases. As the complexity is an important issue...
Device-to-device (D2D) communications is a promising candidate for increasing the throughput of cellular systems towards 5G. Its current consideration for inclusion in LTE-A is attracting a lot of research interest, including work on mode selection, bandwidth allocation, and power control. Some consider the uplink for D2D operation while others focus on operation over the downlink. It is still unclear,...
One of the main advantages of utilizing flexible backhaul in future HetNets is that it can provide better user experience through flexible resource allocation. For this purpose, it is important to provide the required quality of service (QoS) in such networks. In this paper, we consider the problem of cross-layer radio resource management in HetNets with flexible backhaul which guarantees minimum...
This paper describes composite propagation effects of both the median pathloss and shadow fading in the large city. In general, the propagation characteristic for the power profile of received signal has the relative power reduction and fluctuation according to distance to the receiver's location far away from the transmitter. The result of these channel propagation losses is due to the reduction...
In our proposed plan, we try to obtain an optimal power allocation scheme of cognitive radio along with singlehop relay node strategy. Regenerative relaying protocol is used in many previous references and same is true for our case also. Our main objective in this paper is to maximize the overall system capacity with respect to the channel interference coefficients in single-hop Cognitive Radio systems...
Efficient spectrum utilization by secondary users (SU) during the inactivity phase of primary users (PU) is of utmost interest for dynamic spectrum access in a cognitive radio environment. In this paper, we investigate the utilization efficiency of cognitive radio users with respect to the realistic estimate of PU duty cycle (DC) in AWGN and generalized κ-µ fading channels for a fixed interference...
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