| 1. |
- Chai, R., et al.
(författare)
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Utility-based bandwidth allocation algorithm for heterogeneous wireless networks
- 2013
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Ingår i: Science in China, Series F: Information Sciences. - : Springer Science and Business Media LLC. - 1009-2757 .- 1862-2836. ; 56:2, s. 95-107
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Tidskriftsartikel (refereegranskat)abstract
- In next generation wireless network (NGWN), mobile users are capable of connecting to the core network through various heterogeneous wireless access networks, such as cellular network, wireless metropolitan area network (WMAN), wireless local area network (WLAN), and ad hoc network. NGWN is expected to provide high-bandwidth connectivity with guaranteed quality-of-service to mobile users in a seamless manner; however, this desired function demands seamless coordination of the heterogeneous radio access network (RAN) technologies. In recent years, some researches have been conducted to design radio resource management (RRM) architectures and algorithms for NGWN; however, few studies stress the problem of joint network performance optimization, which is an essential goal for a cooperative service providing scenario. Furthermore, while some authors consider the competition among the service providers, the QoS requirements of users and the resource competition within access networks are not fully considered. In this paper, we present an interworking integrated network architecture, which is responsible for monitoring the status information of different radio access technologies (RATs) and executing the resource allocation algorithm. Within this architecture, the problem of joint bandwidth allocation for heterogeneous integrated networks is formulated based on utility function theory and bankruptcy game theory. The proposed bandwidth allocation scheme comprises two successive stages, i.e., service bandwidth allocation and user bandwidth allocation. At the service bandwidth allocation stage, the optimal amount of bandwidth for different types of services in each network is allocated based on the criterion of joint utility maximization. At the user bandwidth allocation stage, the service bandwidth in each network is optimally allocated among users in the network according to bankruptcy game theory. Numerical results demonstrate the efficiency of the proposed algorithm.
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| 2. |
- Gong, Jie, et al.
(författare)
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On precoding for overlapped clustering in a measured urban macrocellular environment
- 2013
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Ingår i: Science in China, Series F: Information Sciences. - : Springer Science and Business Media LLC. - 1009-2757. ; 56:2, s. 38-022301
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we study the performance of precoding schemes for cooperative transmission of multiple coherent base stations (BSs) that allow for overlapped clustering in a measured urban macrocellular environment at 2.66 GHz, in order to verify previous findings obtained by using simulated channel data. The evaluated precoding schemes include zero-forcing (ZF), layered virtual signal-to-interference-plus-noise ratio (SINR) maximization (LVSM) and clustered virtual SINR maximization (CVSM). The results show that the sum rate of the CVSM scheme outperforms the other precoding schemes. In addition, the ZF achieves higher rates than the LVSM, except when the channel condition is poor. When greedy proportional user scheduling is considered, the CVSM scheme and the ZF scheme offer similar performance, whereas the LVSM scheme gives little gain over a non-cooperative transmission scheme used as the baseline.
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| 3. |
- Hou, Xueying, et al.
(författare)
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On channel quantization for multi-cell cooperative systems with limited feedback
- 2013
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Ingår i: Science in China, Series F: Information Sciences. - : Springer Science and Business Media LLC. - 1009-2757. ; 56:2, s. 168-022308
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Tidskriftsartikel (refereegranskat)abstract
- Coherent multi-cell cooperative transmission, also referred to as coordinated multi-point transmission (CoMP), is a promising strategy to provide high spectral efficiency for universal frequency reuse cellular systems. To report the required channel information to the transmitter in frequency division duplexing systems, limited feedback techniques are often applied. Considering that the average channel gains from multiple base stations (BSs) to one mobile station are different and the number of cooperative BSs may be dynamic, it is neither flexible nor compatible to employ a large codebook to directly quantize the CoMP channel. In this paper, we employ per-cell codebooks for quantizing local and cross channels. We first propose a codeword selection criterion, aiming at maximizing an estimated data rate for each user. The proposed criterion can be applied for an arbitrary number of receive antennas at each user and also for an arbitrary number of data streams transmitted to each user. Considering that the resulting optimal per-cell codeword selection for CoMP channel is of high complexity, we propose a serial codeword selection method that has low complexity but yields comparable performance to that of the optimal codeword selection. We evaluate the proposed codeword selection criterion and method using measured CoMP channels from an urban environment as well as simulations. The results demonstrate significant performance gain as compared to an existing low-complexity method.
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| 4. |
- Wang, Hao, et al.
(författare)
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A unified algorithm for mobility load balancing in 3GPP LTE multi-cell networks
- 2013
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Ingår i: Science in China. Series F, Information Sciences. - : Science China Press. - 1009-2757. ; 56
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Tidskriftsartikel (refereegranskat)abstract
- 3GPP long term evolution (LTE) is a promising candidate for the next-generation wireless network, which is expected to achieve high spectrum efficiency by using advanced physical layer techniques and flat network structures. However, the LTE network still faces the problem of load imbalance as in GSM/WCDMA networks, and this may cause significant deterioration of system performance. To deal with this problem, mobility load balancing (MLB) has been proposed as an important use case in 3GPP self-organizing network (SON), in which the serving cell of a user can be selected to achieve load balancing rather than act as the cell with the maximum received power. Furthermore, the LTE network aims to serve users with different quality-of-service (QoS) requirements, and the network-wide objective function for load balancing is distinct for different kinds of users. Thus, in this paper, a unified algorithm is proposed for MLB in the LTE network. The load balancing problem is first formulated as an optimization problem with the optimizing variables being cell-user connections. Then the complexity and overhead of the optimal solution is analyzed and a practical and distributed algorithm is given. After that, the proposed algorithm is evaluated for users with different kinds of QoS requirements, i.e., guaranteed bit rate (GBR) users with the objective function of load balance index and non-GBR (nGBR) users with the objective function of total utility, respectively. Simulation results show that the proposed algorithm leads to significantly balanced load distribution for GBR users to decrease the new call blocking rate, and for nGBR users to improve the cell-edge throughput at the cost of only slight deterioration of total throughput.
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| 5. |
- Xu, X., et al.
(författare)
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Resource pooling for frameless network architecture with adaptive resource allocation
- 2013
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Ingår i: Science in China, Series F: Information Sciences. - : Springer Science and Business Media LLC. - 1009-2757 .- 1862-2836. ; 56:2, s. 83-94
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Tidskriftsartikel (refereegranskat)abstract
- The system capacity for future mobile communication needs to be increased to fulfill the emerging requirements of mobile services and innumerable applications. The cellular topology has for long been regarded as the most promising way to provide the required increase in capacity. However with the emerging densification of cell deployments, the traditional cellular structure limits the efficiency of the resource, and the coordination between different types of base stations is more complicated and entails heavy cost. Consequently, this study proposes frameless network architecture (FNA) to release the cell boundaries, enabling the topology needed to implement the FNA resource allocation strategy. This strategy is based on resource pooling incorporating a new resource dimension-antenna/antenna array. Within this architecture, an adaptive resource allocation method based on genetic algorithm is proposed to find the optimal solution for the multi-dimensional resource allocation problem. Maximum throughput and proportional fair resource allocation criteria are considered. The simulation results show that the proposed architecture and resource allocation method can achieve performance gains for both criteria with a relatively low complexity compared to existing schemes.
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| 6. |
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| 7. |
- Zhang, H., et al.
(författare)
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Multicell power allocation method based on game theory for inter-cell interference coordination
- 2009
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Ingår i: Science China Information Sciences. - : Springer Science and Business Media LLC. - 1869-1919 .- 1674-733X. ; 52:12, s. 2378-2384
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Tidskriftsartikel (refereegranskat)abstract
- As a new technology, coordinated multipoint (CoMP) transmission is included in LTE-Advanced study item. Moreover, the network architecture in LTE-Advanced system is modified to take into account coordinated transmission. Under this background, a novel power allocation game model is established to mitigate inter-cell interference with cellular coordination. In the light of cellular cooperation relationship and centralized control in eNodeB, the power allocation in each served antenna unit aims to make signal to interference plus noise ratio (SINR) balanced among inter-cells. Through the proposed power allocation game algorithm, the users’ SINR can reach the Nash equilibrium, making it feasible to reduce the co-frequency interference by decreasing the transmitted power. Numerical results show that the proposed power allocation algorithm improves the throughput both in cell-center and cell-edge. Moreover, the blocking rate in cell-edge is reduced too.
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