In this paper,we propose optimum and sub-optimum resource allocation and opportunistic scheduling solutions for orthogonal frequency division multiple access(OFDMA)-based multicellular systems. The applicability,compl...In this paper,we propose optimum and sub-optimum resource allocation and opportunistic scheduling solutions for orthogonal frequency division multiple access(OFDMA)-based multicellular systems. The applicability,complexity,and performance of the proposed algorithms are analyzed and numerically evaluated. In the initial setup,the fractional frequency reuse(FFR) technique for inter-cell interference cancellation is applied to classify the users into two groups,namely interior and exterior users. Adaptive modulation is then employed according to the channel state information(CSI) of each user to meet the symbol error rate(SER) requirement. There then,we develop subcarrier-and-bit allocation method,which maximizes the total system throughput subject to the constraints that each user has a minimum data rate requirement. The algorithm to achieve the optimum solution requires high computational complexity which hinders it from practicability. Toward this end,we propose a suboptimum method with the complexity extensively reduced to the order of O(NK),where N and K denote the total number of subcarriers and users,respectively. Numerical results show that the proposed algorithm approaches the optimum solution,yet it enjoys the features of simplicity,dynamic cell configuration,adaptive subcarrier-and-bit allocation,and spectral efficiency. Index TermsAdaptive modulation,fractional frequency reuse,multiuser subcarrier-and-bit allocation,opportunistic scheduling,orthogonal frequency division multiple access.展开更多
在同频组网的LTE-A飞蜂窝系统中,飞蜂窝基站的密集部署会造成较为严重的同频干扰,导致网络吞吐量和用户的服务质量（Quality of Service,QoS）降低.部分频率复用（Fractional Frequency Reuse,FFR）作为常用的干扰协调方案,可以有效地...在同频组网的LTE-A飞蜂窝系统中,飞蜂窝基站的密集部署会造成较为严重的同频干扰,导致网络吞吐量和用户的服务质量（Quality of Service,QoS）降低.部分频率复用（Fractional Frequency Reuse,FFR）作为常用的干扰协调方案,可以有效地提高边缘用户的服务质量.在FFR方案的基础上,通过结合遗传算法和基于模拟退火的图着色算法,提出了一种智能优化部分频率复用（Intelligence-FFR,I-FFR）算法.该算法能够动态地调整中心区域所占比例和边缘区域的频率复用因子,以增加宏小区吞吐量,降低小区边缘区域用户的中断概率.仿真结果表明,与FFR-3干扰协调算法相比,提出的I-FFR算法可使宏小区吞吐量提升15％,同时边缘区域平均用户的中断概率从85％降低到40％.展开更多
In order to address spectrum resource scarcity in traditional cellular networks,television(TV)white space is considered as a potential solution to offload a portion of network traffic and enlarge network capacity.This...In order to address spectrum resource scarcity in traditional cellular networks,television(TV)white space is considered as a potential solution to offload a portion of network traffic and enlarge network capacity.This paper describes a cognitive cellular network which allocates low geometry users to the TV white space based on a proportional fair criterion.An uplink user allocation scheme is proposed and the validity of the proposed scheme is established by simulation of the cellular network usage in conjunction with the TV white space.The simulation results show clear improvements in both the user and the system performance with the cognitive coexistent cellular network compared with the traditional cellular network,and that the performance of the proposed user allocation scheme is superior to other user allocation schemes.展开更多
In this paper, we present a technique called 'fuzzy cells' that builds on the multicarrier features of Long Term Evolution-Advanced (LTE-A) and high-speed packet access (HSPA). Multiple carriers are aggregated...In this paper, we present a technique called 'fuzzy cells' that builds on the multicarrier features of Long Term Evolution-Advanced (LTE-A) and high-speed packet access (HSPA). Multiple carriers are aggregated to create a larger system bandwidth, and these carriers are transmitted at different powers by each sector antenna. This creates a set of cell-edge locations that differ from one frequency to the next. System-level simulations are performed to estimate individual user and average throughput for a hexagonal deployment of 3-sector base stations. For moderately high loads, a fuzzy cell deployment can improve tenth percentile (cell-edge) user throughput by 100% and can improve average throughput by about 30% compared with a reuse 1 scheme. Fuzzy cells reduce inter-cell interference in the same way as higher-order reuse schemes and allow users to access the full system bandwidth.展开更多
Co-frequency and co-time full duplex(CCFD) is a promising technique for improving spectral efficiency in next generation wireless communication systems. However, for the applications of CCFD in a cellular network, sev...Co-frequency and co-time full duplex(CCFD) is a promising technique for improving spectral efficiency in next generation wireless communication systems. However, for the applications of CCFD in a cellular network, severe co-channel interference is an essential problem. Specifically, there are two significant interferences, i.e., inter-terminal interference(ITI) and inter-cell interference(ICI), which lead to an obvious performance degradation. In this paper, two techniques are proposed for suppressing the ITI and ICI in a CCFD cellular system, respectively. The first technique is obtained by modeling the three-node CCFD system as the Z-channel. After deriving the sum-capacity of the Z-channel, a sum-capacity-achieving scheme based on successive interference cancellation(SIC) is proposed. The second technique is designed by combining the fractional frequency reuse scheme with CCFD. The performance gains of the proposed two techniques in terms of signalto-interference plus noise ratio(SINR) and sumcapacity are analyzed. Simulation results show that the proposed scheme can achieve significant interference suppression performance and higher system capacity, especially for cell edge users.展开更多
文摘In this paper,we propose optimum and sub-optimum resource allocation and opportunistic scheduling solutions for orthogonal frequency division multiple access(OFDMA)-based multicellular systems. The applicability,complexity,and performance of the proposed algorithms are analyzed and numerically evaluated. In the initial setup,the fractional frequency reuse(FFR) technique for inter-cell interference cancellation is applied to classify the users into two groups,namely interior and exterior users. Adaptive modulation is then employed according to the channel state information(CSI) of each user to meet the symbol error rate(SER) requirement. There then,we develop subcarrier-and-bit allocation method,which maximizes the total system throughput subject to the constraints that each user has a minimum data rate requirement. The algorithm to achieve the optimum solution requires high computational complexity which hinders it from practicability. Toward this end,we propose a suboptimum method with the complexity extensively reduced to the order of O(NK),where N and K denote the total number of subcarriers and users,respectively. Numerical results show that the proposed algorithm approaches the optimum solution,yet it enjoys the features of simplicity,dynamic cell configuration,adaptive subcarrier-and-bit allocation,and spectral efficiency. Index TermsAdaptive modulation,fractional frequency reuse,multiuser subcarrier-and-bit allocation,opportunistic scheduling,orthogonal frequency division multiple access.
文摘在同频组网的LTE-A飞蜂窝系统中,飞蜂窝基站的密集部署会造成较为严重的同频干扰,导致网络吞吐量和用户的服务质量（Quality of Service,QoS）降低.部分频率复用（Fractional Frequency Reuse,FFR）作为常用的干扰协调方案,可以有效地提高边缘用户的服务质量.在FFR方案的基础上,通过结合遗传算法和基于模拟退火的图着色算法,提出了一种智能优化部分频率复用（Intelligence-FFR,I-FFR）算法.该算法能够动态地调整中心区域所占比例和边缘区域的频率复用因子,以增加宏小区吞吐量,降低小区边缘区域用户的中断概率.仿真结果表明,与FFR-3干扰协调算法相比,提出的I-FFR算法可使宏小区吞吐量提升15％,同时边缘区域平均用户的中断概率从85％降低到40％.
基金Supported by the National Natural Science Foundation of China （No.61271230）,the Starting Fund for Science Research of NJIT （No.YKJ201205） and the Open Research Fund of National Mobile Communications Research Laboratory （No.2013D02）.
文摘In order to address spectrum resource scarcity in traditional cellular networks,television(TV)white space is considered as a potential solution to offload a portion of network traffic and enlarge network capacity.This paper describes a cognitive cellular network which allocates low geometry users to the TV white space based on a proportional fair criterion.An uplink user allocation scheme is proposed and the validity of the proposed scheme is established by simulation of the cellular network usage in conjunction with the TV white space.The simulation results show clear improvements in both the user and the system performance with the cognitive coexistent cellular network compared with the traditional cellular network,and that the performance of the proposed user allocation scheme is superior to other user allocation schemes.
文摘In this paper, we present a technique called 'fuzzy cells' that builds on the multicarrier features of Long Term Evolution-Advanced (LTE-A) and high-speed packet access (HSPA). Multiple carriers are aggregated to create a larger system bandwidth, and these carriers are transmitted at different powers by each sector antenna. This creates a set of cell-edge locations that differ from one frequency to the next. System-level simulations are performed to estimate individual user and average throughput for a hexagonal deployment of 3-sector base stations. For moderately high loads, a fuzzy cell deployment can improve tenth percentile (cell-edge) user throughput by 100% and can improve average throughput by about 30% compared with a reuse 1 scheme. Fuzzy cells reduce inter-cell interference in the same way as higher-order reuse schemes and allow users to access the full system bandwidth.
基金jointly supported by the HongKong,Macao and Taiwan Science & Technology Cooperation Program of China(Grant no.2015DFT10170)the Beijing Higher Education Young Elite Teacher Project
文摘Co-frequency and co-time full duplex(CCFD) is a promising technique for improving spectral efficiency in next generation wireless communication systems. However, for the applications of CCFD in a cellular network, severe co-channel interference is an essential problem. Specifically, there are two significant interferences, i.e., inter-terminal interference(ITI) and inter-cell interference(ICI), which lead to an obvious performance degradation. In this paper, two techniques are proposed for suppressing the ITI and ICI in a CCFD cellular system, respectively. The first technique is obtained by modeling the three-node CCFD system as the Z-channel. After deriving the sum-capacity of the Z-channel, a sum-capacity-achieving scheme based on successive interference cancellation(SIC) is proposed. The second technique is designed by combining the fractional frequency reuse scheme with CCFD. The performance gains of the proposed two techniques in terms of signalto-interference plus noise ratio(SINR) and sumcapacity are analyzed. Simulation results show that the proposed scheme can achieve significant interference suppression performance and higher system capacity, especially for cell edge users.
渝公网安备 50019002500403号违法和不良信息举报中心