A soft fractional frequency reuse scheme is proposed to fulfill full frequency reuse for the 4G mobile communications system. This scheme can be implemented in three types,and using what type of the scheme can be deci...A soft fractional frequency reuse scheme is proposed to fulfill full frequency reuse for the 4G mobile communications system. This scheme can be implemented in three types,and using what type of the scheme can be decided during practical applications,depending on the link gain of the physical layer. The implementation of soft fractional frequency reuse in one of the three types is studied. The study results show that the frequency reuse factor of this scheme may reach 1/3-1. The simplified form of this scheme has been successfully applied in the 4G experimental network in Shanghai ,and provides a way to fulfill full frequency reuse in systems.展开更多
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, ...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 suboptimum method with the reduced to the order of O(NIO, the total number of subcarriers end, we complexity propose a extensively where N and K denote 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 subearrier-and-bit allocation, and spectral efficiency.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 t...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 ceils 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
基金the National Natural Science Foundation of China under Grant 60496312863 Program of China under Grants 2003AA12331004 and 2006AA01Z260.
文摘A soft fractional frequency reuse scheme is proposed to fulfill full frequency reuse for the 4G mobile communications system. This scheme can be implemented in three types,and using what type of the scheme can be decided during practical applications,depending on the link gain of the physical layer. The implementation of soft fractional frequency reuse in one of the three types is studied. The study results show that the frequency reuse factor of this scheme may reach 1/3-1. The simplified form of this scheme has been successfully applied in the 4G experimental network in Shanghai ,and provides a way to fulfill full frequency reuse in systems.
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 suboptimum method with the reduced to the order of O(NIO, the total number of subcarriers end, we complexity propose a extensively where N and K denote 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 subearrier-and-bit allocation, and spectral efficiency.
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 ceils reduce inter-cell interference in the same way as higher-order reuse schemes and allow users to access the full system bandwidth.