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Hybrid precoding is widely studied in millimetre-wave (mmWave) massive MIMO systems due to low cost as well as low power consumption. In general, there are two kinds of hybrid precoding structures: one is fully connected structure (FCS), where each radio frequency (RF) chain is connected to all antennas, and the other is partially connected structure (PCS), where each RF chain is connected to a sub-array...
Licensed-assisted access (LAA) to unlicensed spectrum has drawn the worldwide attention from academia and industry since its emergence at the Third Generation Partnership Project in 2015. As a key technology for Long Term Evolution unlicensed spectrum deployment, LAA goes far toward solving the coexistence problems in the 5-GHz unlicensed bands. However, owing to unpredictable interference from unlicensed-band...
This paper investigates a typical optimization problem for 60 GHz multiuser hybrid beamforming, which is to maximize the minimal SINR over all of the considered subcarriers under a total power constraint. In order to reduce the complexity, two methods of using the fixed analog beamforming (ABF) weights are presented rather than traditional iterative methods, which are codebook-based method and singular...
Recently, hybrid analog/digital beamforming (BF) system is attracting increasing attention in the study on multiuser millimeter wave systems. In these systems, a relatively large number of antennas are connected to a less number of analog front-end chains so as to reduce both of the hardware complexity and power consumption. This paper investigates on optimizing phase-only analog BF and digital BF...
Power consumption and costs of the analog front-end (AFE) chains are often not negligible for large-scale antenna array systems. A low-complexity hardware architecture is to use a number of AFE chains that is less than the number of the antennas. Beamforming for this low-complexity hardware architecture involves both digital and analog beamforming, which is termed hybrid analog/digital beamforming...
Wireless multimedia Quality of Experience (QoE) is not only a matter of Quality of Service (QoS). Network-based metrics such as delay, jitter and packet loss are critical indicators for multimedia service; but not well enough without considering the intelligent terminal-related metrics. This paper present a new QoE Evaluation Model which integrates application, network and terminal layers factors...
Device-to-Device (D2D) communication is considered to be a promising resource reuse technology for local users. Unlike the previous studies on centralized scheduling methods, we develop several distributed resource management schemes for D2D communication underlay cellular networks. In the distributed resource management framework, each D2D user independently decides the transmit resources and power...
In this paper, we propose an algorithm to solve the joint frequency resource and transmission power allocation problem for heterogeneous network (HetNet) of LTE-Advanced (LTE-A) systems, which consiste of several types of base station nodes, such as macrocell, picocell (hotzone), femtocell and relay. The optimization problem is formulated to minimize the sum downlink interference power level of all...
This paper studies the resource allocation problem in orthogonal frequency division multiple access (OFDMA) cooperative relaying cellular systems. Most existing work on resource allocation does not fully consider all the influential factors for such systems. In the paper, we formulate the optimization problem for resource allocation, including relay selection, subcarrier assignment, and power allocation...
In this paper, we propose a cooperative load balancing scheme focusing on improving effective resource utilization and mitigate the co-channel interference across domains through fair resource allocation in heterogeneous network (Het-Net). We models the load balancing issue as an optimization problem for minimizing the effective resource utilization. Simulation results have demonstrated that the system...
In order to solve the problem that the existing resource allocation strategies cannot give integrative consideration to QoS, spectrum efficiency for mixed traffic, this paper proposes a utility-based resource allocation algorithm for mixed traffic in wireless networks. The unified utility function for users with different traffics is studied first. After that, the optimization model for the resource...
A novel coordinated scheduling algorithm for OFDM-based systems in multi-cell scenario is proposed in this paper. The studied algorithm based on the utility function is general for the downlink of networks. The algorithm coordinates the subcarrier assignment over the BS cluster. We first establish the framework for this inter-cell coordinated optimization problem through utility-based method. The...
Coordinated scheduling is a hot topic recently. Inter-cell interference is crucial to the improvement of system throughput, especially in OFDMA system. In this work, the optimization of beamforming in multiple-input single-output (MISO) downlink system is considered. The uplink-downlink duality has been widely used in this sort of research. By the conclusion of a previous work, we provide some practical...
OFDM has become one of the most important Beyond-3G transmission technologies. Mobile WiMAX is a typical representative of OFDM systems. The cross-layer optimization problem of inter-cell coordinated resource allocation for OFDM systems is addressed in this paper. We first analyze the problem by utility-based method, and formulate this optimization problem. Then the globally optimal and a sub-optimal...
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