| The Internet is associated with human activities increasingly closely.The higher information transmission rate will be pursued by the next generation networks.The multipleinput multiple-output(MIMO)technology improves system capacity with the multipath effect generated by multi-antenna and is therefore of great concern.In the fifth generation(5G)mobile communication networks,various small communication devices will gradually spread all over daily life.However,due to the small size and high hardware implementation complexity,the number of antennas that can be arranged in the device is limited.So that the capabilities of MIMO technology are limited.Superposition virtual channel(SVC)technology is designed to improve the transmission rate without increasing the number of antennas.It can effectively solve the problem of limited transmission rate due to the limited number of antennas in MIMO systems.It is obvious that SVC technology has a wide application prospect.However,few literatures have so far studied SVC technology or systems using this technology.Therefore,the research in this paper is based on the SVC MIMO systems.The quality of service(QoS)guarantee in wireless communication cannot be ignored.Applications of the Internet will generate a wide variety of services,which with different QoS requirements may exist in one communication system.In order to provide users good experience,systems that carry services of diverse QoS requirements must have heterogeneous QoS guarantee(HQG)capabilities.However,the current researches on SVC MIMO systems are still at the physical layer,and there is no reports has been published on QoS guarantee or heterogeneous QoS guarantee in SVC MIMO systems.Effective capacity(EC),as an indicator of considering statistical delay QoS constraints from the link layer,often plays an important role in the study of QoS guarantee problems.Therefore,this paper will embed the heterogeneous QoS guarantee into the uplink communication of SVC MIMO systems.Under the new system model,EC of the system will be studied,and system performance will be optimized and analyzed.The main work of this paper is as follows:First,this paper designs SVC MIMO systems that guarantee QoS requirements forheterogeneous services.In order to meet the different delay-QoS requirements of heterogeneous services,a heterogeneous QoS guaranteed superposition virtual channel(HQG-SVC)technology that guarantees heterogeneous QoS requirements is proposed.Then the HQG-SVC MIMO system model is established.Considering that the Nakagami-m fading model is more suitable for the fading of the actual channel,this paper derives the normalized EC closure expression of the HQG-SVC MIMO systems with Nakagami-m fading channels according to the EC theory.Normalized EC is the EC per unit bandwidth.Targeting at maximizing the normalized EC and obtaining better BER,an optimization problem is established to obtain the optimal HQG-SVC coefficient vector.In order to simplify the multiobjective problem,we make the magnitudes of normalized EC and BER on the same order through mathematical treatment and design a weighting fitness function of these two metrics.Second,in order to further understand the reasons that limit HQG-SVC MIMO system performance and under what conditions the system performance can be better,this paper explores how the factors,such as modulation mode,number of virtual channels and antenna correlation,influence BER and EC.It is analyzed why and how the above factors can affect system performance.Since the effect of antenna correlation is directly reflected on the channel quality which restricts the EC of the system,there is an internal correlation between the antenna correlation and the EC.This paper derives the closed-form expression of system normalized EC under the antenna correlation.Based on the numerical characteristics of the normalized EC under this condition,the EC metrics in the joint optimization problem are redesigned to keep the two metrics on the same magnitude. |
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