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In this paper, we evaluate the outage probability and bit error rate (BER) performances of a three terminal full-duplex relaying (FDR) system with non-negligible residual self-interference (RSI). By investigating the signal-to-interference-plus-noise ratios (SINRs) at the relay and the destination respectively, the exact outage probability and BER of decode-and-forward (DF) based FDR system over Nakagami-m...
In cellular networks, proximity users may communicate directly without going through the infrastructure such as the base station (BS), which is device-to-device (D2D) communications, and it can improve spectral efficiency. However, enabling D2D communications in a cellular network poses two major challenges. First, the BS is suffered from signaling overhead. Second, D2D transmitters may cause harmful...
This paper investigates energy efficient resource allocation for orthogonal frequency division multiplexing (OFDM) multi-relay networks, where the source node communicates with the destination node via multiple relay nodes. Both transmit power and circuit power consumption are taken into consideration. The objective is to minimize the overall power consumption so as to achieve high energy efficiency...
In this paper, outage performance of Physical Layer Network Coding (PLNC) based half duplex Cognitive Radio Relay (CRR) system with two source and destination nodes is analyzed in overlay and underlay spectrum sharing schemes. Using Decode and Forward (DF) relay, two source nodes send data to both the destination nodes in two time slots when there is large fading and path loss between one of the source...
Over the last decade, the growing amount of UL and DL mobile data traffic has been characterized by substantial asymmetry and time variations. Dynamic time-division duplex (TDD) has the capability to accommodate to the traffic asymmetry by adapting the UL/DL configuration to the current traffic demands. In this work, we study a two-tier heterogeneous cellular network (HCN) where the macro tier and...
Cooperative spectrum sensing (CSS) achieves spatial diversity and is used to combat shadowing and fading in sensing. In reality, spectrum sensing in TV band may also face challenges caused by interference from secondary users (SU). Unfortunately, this issue has not yet been sufficiently discussed. In this work, we propose a CSS to mitigate impact of SU interference and maintain robust sensing. After...
This paper proposes variable step closed loop power control algorithm combined with space diversity to improve the performance of High Altitude Platforms (HAPs) communication at low elevation angle using Code Division Multiple Access (CDMA). In this contribution, we first develop HAPs channel model which is derived from experimental measurement. From our experiment, we found HAPs channel characteristic...
This paper studies the impact of primary user interference and imperfect estimation of channel between secondary transmitter and primary receiver on the ergodic capacity of secondary user in a spectrum sharing environment under an average received-power constraint, in presence of Rayleigh fading. We consider that a secondary user is allowed to access the spectral band allocated to a primary user as...
In this paper, we study the power allocation for both regenerative and non-regenerative relay transmission over Rayleigh fading channels in cognitive networks. Based on the analyses of features of cognitive networks, a relevant interference model is first built over Rayleigh fading channels. Then, we propose a combined power allocation strategy in order to minimize the outage probabilities in the...
In correlated Rician flat fading environments, we consider a single input multiple output (SIMO) system with a large-scale antenna array. We assume that the receiver only knows the channel information related to the specular component and treat the Rayleigh fading component as interference. We first present a maximum-ratio-combining (MRC) -like detection scheme only based on the specular component,...
We propose a dynamic interference mitigation technique by incorporating cognitive capability and cooperative mechanism in two tier heterogeneous network (HetNet) with open access femtocells. To further enhance protection of victim user that is subject to interference, a cooperative mechanism is designed based on received power of user. We exploit stochastic geometry for modelling and analysing the...
This paper investigates the aggregate interference from interweave cognitive secondary nodes spatially distributed in a finite Poisson field. These secondary nodes sense an out-of-band beacon to initiate their transmissions, which can be concurrent with those of the primary system if a sensing error is made. The resulting aggregate interference is analyzed in this paper. For this purpose, general...
In this paper, we derive the random coding error exponent of amplify-and-forward (AF) relay networks in presence of arbitrary number of independent and identically distributed (i.i.d.) interferers both at the relay and the destination. Multiuser networks are common examples of interference limited networks. We derive the ergodic capacity of the network and present simulation results on the performance...
In this paper, we consider an extension of the cognitive radio channel model in which the secondary transmitter has to obtain (learn) the primary message rather than having non-causal knowledge of it. We formulate an achievable rate region that combines elements of compress-and-forward relaying with coding for the pure cognitive radio channel model. Moreover, we provide parameters design that maximizes...
In this paper, we examine the impact of antenna correlation on transmit antenna selection with receive maximal ratio combining (TAS/MRC) in multiple-input multiple-output multiuser network (MUN-MIMO) with single source , M destinations with underlay spectrum sharing over Nakagami-m fading environment. The secondary network under consideration is equipped with multiple correlated antennas at each node...
Pilot contamination is an issue affecting massive MIMO systems. It is known that a time-shifted pilot method can be used to reduce pilot contamination from neighboring cells when the number of antennas at the base station is infinitely large [1]. In our research, we analyze the effect of a finite number of antennas on the sum rate of the time-shifted method. Numerical results show that the time-shifted...
In next-generation mobile networks e.g., Long Term Evolution Advanced (LTE-A) the conventional macro cell structure is under laid with small cells in order to fulfill the strict QoS (Quality of Service) requirements. Smaller cells offer better receiving conditions for nearby users, thus the usage of small cells ensure throughput enhancement. On the other hand, small cells are considered as interference...
Erroneous beacon detection by interweave secondary nodes generates interference on the primary system. This paper analyzes how the aggregate interference behaves when secondary nodes use transmit power control and receiver association schemes. For this purpose, secondary transmitter nodes and receiver nodes are assumed to be distributed over a circular region and over the entire 2-D plane respectively...
Self-organizing network is used for regional communications, which makes up for the coverage of mobile communication system. In LTE-Advanced network, such network forms by proximity communications and utilizes the limited bandwidth efficiently. However, the system frequencies shared by the terminals in self-organizing network belong to cellular terminals, the resource reusing leads to interference...
In this paper we have integrated Game theory framework, effective capacity theory and interference minimization for power allocation analysis over fading multiple access channels (MAC). Game theory is a powerful tool for modeling selfish behavior of competitors in resource allocation contest and can be used effectively in designing and modeling behavior of users in distributed resource allocation...
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