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The emergence of 5G wireless communication calls for new paradigms to satisfy the individuation and diversification of users' demands. In this paper, we construct the multicast groups under the guidance of user interest and then allocate the subcarriers and power to these groups in orthogonal frequency division multiple (OFDM) networks. Specifically, in order to maximize the social utility related...
Orthogonal frequency division multiple access (OFDMA) is an effective method to reduce inter symbol interference in LTE systems. Doppler shift, however, leads to a loss of sub-channel orthogonality, resulting in inter-channel interference in high speed environment. Firstly, this paper develops the mathematical formulae describing the interference on resource block (RB) which is the smallest resource...
Recently, interference problem between WiFi devices is serious by thoughtlessly installation of access points (APs). To solve this problem, we suggest interference alignment (IA) algorithm and analyze the link level performance of IA in IEEE 802.11ac specification.
Road transportation is one of the main sources of environmental pollution. Electrification seems like the ideal solution for reducing CO2 emissions, while maintaining all the advantages of modern means of transportation. The shift to electric vehicles needs to be accompanied by an appropriate telecommunications network, which is responsible for the reliable transmission of large volumes of information...
As a promising technology, Device-to-Device (D2D) communication can bring some advantages such as high bit rates, low delays, low power consumption by reusing frequency band with the cellular user equipments (UEs). While at the same time, inter-cell and intra-cell interference is inevitable. In this paper, we propose an algorithm Stackelberg game based to jointly allocate power and resources when...
We propose an optimal asymmetric resource allocation (ARA) algorithm for the decode-and-forward (DF) dualhop multi-relay Long Term Evolution Advanced (LTE-Advanced) system in the downlink, with orthogonal frequency division multiplexing (OFDM) transmission. Our work is different in that the time slots for the two hops via each of the relays are designed to be asymmetric, i.e., with K relays in the...
In 3GPP Long Term Evolution (LTE) networks, the frequency reuse schemes such as fractional frequency reuse (FFR) and soft frequency reuse (SFR) are used to improve system capacity. The allocation of transmit power and subcarriers to each cell in these schemes are fixed prior to network deployment. This limits the potential performance of these frequency reuse schemes. In this paper, we propose to...
In this paper we propose a novel resource allocation scheme to achieve a balanced performance improvement for all users in a LTE network subject to inter-cell interference. In the proposed scheme the resource allocation process is implemented in two steps. In the first step interference coordination and scheduling are first conducted in a global manner to prevent cell-edge users from mutual interference...
In a wireless network, multi-user diversity can be employed to improve system throughput performance by scheduling the channel to the user with the best instantaneous channel state information (CSI). However, the overhead induced by polling CSIs of a large number of users can overshadow the multi-user diversity gain. In our previous work, a user identification approach (UIDA) was proposed to reduce...
This paper focuses on the subchannel and power allocation for mixed multicast and unicast traffic in wireless OFDMA networks, where the multicast data is divided into basic layer and enhancement layer data. Our goal is to maximize the network total throughput with a total power constraint while guaranteeing the minimum rate requirement of both the unicast and muticast traffic. A heuristic allocation...
Fractional frequency reuse (FFR) is an efficient method to suppress inter-cell interference (ICI) in multi-cell OFDMA networks. In this paper, the optimal threshold is designed for FFR schemes to identify cell central and edge users. We first derive throughput of the FFR scheme considering small-scale fading channels and different scheduling strategies. Then we conclude from the analysis and simulation...
In this paper, we investigate the benefits of using cooperative relays in interweave (opportunistic) cognitive radio systems. A novel distributed space frequency (DSF) code for relay cooperation is presented. The code is designed to be a multi-user multi-OFDM channels code. It achieves a cooperative diversity gain of order NL for all users, where N is the number of relays and L is the number of paths...
For the issue of resource allocation in a heterogeneous multi-user downlink OFDMA system with both delay-constrained (DC) and non-delay-constrained (NDC) traffic, this paper proposes suboptimal joint subcarrier and power allocation (JSPA) for channel-aware queue-aware(CAQA) scheduling. The objective is to maximize the sum of all NDC users' logarithmic utility functions (achieving proportional fairness)...
Performance degradation of Cell Centre UEs (CCUs) and "Interference Flooding" phenomenon may happen in Single-Carrier Frequency Division Multiplexing Access (SC-FDMA) uplinks. To decrease the impact of Interference Flooding and improve the CCUs' throughputs, this paper proposes a UE-Interfering-Area (UIA) based Inter-Cell Interference Coordination (IOC) scheme. Using UIA scheme, the eNodeB...
The adaptive resource allocation will be a key technique of the OFDMA systems in the future wireless networks due to the great improvement of the network throughput. However, in order to allocate the subcarriers and power adaptively, the users need to send back the channel state information (CSI) periodically to the base station. The feedback overhead is huge, and it brings a big burden to the uplink...
Multi-user diversity can be exploited in a wireless communication network to significantly increase system throughput through allocating the channel to the user with the best instantaneous channel condition. However, the overhead incurred in polling channel state information (CSI) in a large network can outweigh the gain of multi-user diversity. In our previous work, a user identification approach...
WiMAX is one of the most promising technologies which is to go through wireless broadband last mile access. Handover procedure plays a crucial role in the mobile WiMAX application. This paper introduces an implementable enhanced handover target cell selection algorithm for WiMAX network based on the effective capacity estimation and neighbor advertisement which can effectively avoid the ping-pong...
This paper proposes a novel semi-dynamic inter-cell interference coordination (ICIC) scheme for multi-cell OFDMA systems. The objective of the novel scheme is to strike a balance between ICI minimization and frequency reuse factor (FRF) maximization. Firstly, we divide cell-edge users into non-overlapping user groups based on users' geometry, and classify each group's available bandwidth, which includes...
IEEE802.16e WirelessMAN-OFDMA is expected to be a significant step in the evolution of communication technologies for the provision of broadband services to mobile users. Due to the large amount of parameters to be taken into account, from physical to upper layers, and the degrees of freedom left to manufacturers and operators, a simulation tool is almost mandatory along the path toward implementation...
In orthogonal frequency division-multiple access (OFDMA) systems, the available downlink frequency is divided into subbands which are shared among users. The transmitter determines the users that are scheduled on each subband, and the data rate for each user. To enable these transmitter choices, each user feeds back a channel quality indicator (CQI), giving a compressed version of its observed signal-to-interference-noise...
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