| 1. |
- You, Xiaohu, et al.
(författare)
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Towards 6G wireless communication networks: vision, enabling technologies, and new paradigm shifts
- 2021
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Ingår i: Science China Information Sciences. - : Science Press. - 1674-733X .- 1869-1919. ; 64:1
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Forskningsöversikt (refereegranskat)abstract
- The fifth generation (5G) wireless communication networks are being deployed worldwide from 2020 and more capabilities are in the process of being standardized, such as mass connectivity, ultra-reliability, and guaranteed low latency. However, 5G will not meet all requirements of the future in 2030 and beyond, and sixth generation (6G) wireless communication networks are expected to provide global coverage, enhanced spectral/energy/cost efficiency, better intelligence level and security, etc. To meet these requirements, 6G networks will rely on new enabling technologies, i.e., air interface and transmission technologies and novel network architecture, such as waveform design, multiple access, channel coding schemes, multi-antenna technologies, network slicing, cell-free architecture, and cloud/fog/edge computing. Our vision on 6G is that it will have four new paradigm shifts. First, to satisfy the requirement of global coverage, 6G will not be limited to terrestrial communication networks, which will need to be complemented with non-terrestrial networks such as satellite and unmanned aerial vehicle (UAV) communication networks, thus achieving a space-air-ground-sea integrated communication network. Second, all spectra will be fully explored to further increase data rates and connection density, including the sub-6 GHz, millimeter wave (mmWave), terahertz (THz), and optical frequency bands. Third, facing the big datasets generated by the use of extremely heterogeneous networks, diverse communication scenarios, large numbers of antennas, wide bandwidths, and new service requirements, 6G networks will enable a new range of smart applications with the aid of artificial intelligence (AI) and big data technologies. Fourth, network security will have to be strengthened when developing 6G networks. This article provides a comprehensive survey of recent advances and future trends in these four aspects. Clearly, 6G with additional technical requirements beyond those of 5G will enable faster and further communications to the extent that the boundary between physical and cyber worlds disappears.
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| 2. |
- Chen, Xin, 1980, et al.
(författare)
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Improved resource allocation strategy in SU-CoMP network
- 2011
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Ingår i: The Journal of China Universities of Posts and Telecommunications. - 2210-5123. ; 18:4, s. 7-12
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Tidskriftsartikel (refereegranskat)abstract
- Coordinated Multi-Point transmission and reception (CoMP) for single user, named as SU-CoMP, is considered as an efficient approach tomitigate inter-cell interference in Orthogonal Frequency Division Multiple Access (OFDMA) systems. Two prevalent approaches in SU-CoMP areCoordinated Scheduling (CS) and Joint Processing (JP). Although JP in SU-CoMP has been proved to achieve a great link performanceimprovement for the cell-edge user, efficient Resource Allocation (RA) on the system level is quite needed. However, so far limited work has beendone considering JP, and most existing schemes achieved the improvement of cell-edge performance at cost of the cell-average performancedegradation compared to the single cell RA. In this paper, a two-phase strategy is proposed for SU-CoMP networks. CS and JP are combined toimprove both cell-edge and cell-average performance. Compared to the single cell RA, simulation results demonstrate that, the proposed strategyleads to both higher cell-average and cell-edge throughput.
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| 3. |
- Chen, Xin, 1980, et al.
(författare)
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Optimal and Efficient Power Allocation for OFDM Non-Coherent Cooperative Transmission
- 2012
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Ingår i: IEEE Wireless Communications and Networking Conference, WCNC. - 1525-3511. - 9781467304375 ; , s. 1584-1589
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Konferensbidrag (refereegranskat)abstract
- In this paper, we study the subchannel (SC) power allocation for orthogonal frequency division multiplexing (OFDM) multiple access points (APs) systems with non-coherent cooperative transmission. The objective is to maximize the total capacity under per-AP power constraints. It can be proved that the optimal solution can be obtained by the combination of an optimal SC partition search and the power allocation across SCs for each feasible partition. Existing work exhaustively searched the optimal SC partition and used Lagrange dual method to compute the power allocation across SCs. Since the entire complexity increases exponentially with the number of SCs, the existing method is unsuitable for practical implementation. In this paper, we propose a novel optimal power allocation algorithm for non-coherent cooperative transmission with a much lower complexity. Firstly, a concept of “cut-off SC” is proposed for searching the optimal SC partition. Then, an efficient optimal power allocation algorithm across SCs is proposed for any given cut-off SC. Simulation results demonstrate that the proposed algorithm is optimal with a polynomial complexity, and ends within an acceptable number of iterations.
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| 4. |
- Li, Jingya, 1986, et al.
(författare)
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A novel frequency reuse scheme for coordinated multi-point transmission.
- 2010
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Ingår i: IEEE Vehicular Technology Conference Spring, Taipei, Taiwan, May 2010. - 1550-2252. - 9781424425198 ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- Coordinated Multi-Point (CoMP) transmission is considered in 3GPP LTE-Advanced as a key technique to improve the cell-edge performance. In order to support joint resource allocation among coordinate cells in CoMP systems, efficient frequency reuse schemes need to be designed. However, most of the existing frequency reuse schemes are not suitable for CoMP transmission due to not considering multi-cell joint transmission scenario in their frequency reuse rule. To solve this problem, a cooperative frequency reuse (CFR) scheme is proposed in this paper, which divides the cell-edge area of each cell into two types of zones, and defines a frequency reuse rule to support CoMP transmission for users in these zones. Compared with the conventional soft frequency reuse (SFR) scheme, simulation results demonstrate that the CFR scheme reduces the blocking probability by more than 50%, and improves the cell-edge throughput by 30~40%, with 5~9% additional cell-average throughput.
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| 5. |
- Li, Jingya, 1986, et al.
(författare)
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Downlink Radio Resource Allocation for Coordinated Cellular OFDMA Networks
- 2010
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Ingår i: IEICE Transactions on Communications. - 1745-1345. ; E93B:12, s. 3480-3488
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Tidskriftsartikel (refereegranskat)abstract
- Base station coordination is considered as a promising technique to mitigate inter-cell interference and improve the cell-edge performance in cellular orthogonal frequency division multiple-access (OFDMA) networks. The problem to design an efficient radio resource allocation scheme for coordinated cellular OFDMA networks incorporating base station coordination has been only partially investigated. In this contribution, a novel radio resource allocation algorithm with universal frequency reuse is proposed to support base station coordinated transmission. Firstly, with the assumption of global coordination between all base station sectors in the network, a coordinated subchannel assignment algorithm is proposed. Then, by dividing the entire network into a number of disjoint coordinated clusters of base station sectors, a reduced-feedback algorithm for subchannel assignment is proposed for practical use. The utility function based on the user average throughput is used to balance the efficiency and fairness of wireless resource allocation. System level simulation results demonstrate that the reduced-feedback subchannel assignment algorithm significantly improves the cell-edge average throughput and the fairness index of users in the network, with acceptable degradation of cell-average performance.
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| 6. |
- Li, Jingya, 1986, et al.
(författare)
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Multi-Beam Cooperative Frequency Reuse for Coordinated Multi-Point Systems
- 2010
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Ingår i: Journal of China Universities of Posts and Telecommunications. - 1005-8885. ; 17:6, s. 11-18
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Tidskriftsartikel (refereegranskat)abstract
- Coordinated Multi-Point (CoMP) transmission is considered in 3GPP LTE-Advanced as a key technique to mitigate inter-cell interference and improve the cell-edge performance. To apply CoMP joint transmission effectively, efficient frequency reuse schemes need to be designed to support resource management cooperation among coordinated cells. However, most of the existing frequency reuse schemes are not suitable for CoMP systems due to not considering multi-point cooperative transmission scenario in their frequency reuse rules. In addition, the restrictions of frequency resources in those schemes result in high blockingprobability. To solve the above two problems, a multi-beam cooperative frequency reuse (MBCFR) scheme is proposed in this paper, which reuses all the available frequency resources in each sector and supports multi-beam cooperative transmission for cell-edge users. Besides, the blocking probability is proved to be efficiently reduced. Then, a frequency-segment-sequence based MBCFR scheme is introduced to further reduce the inter-cell interference. System level simulations demonstrate that the proposedscheme results in higher cell-edge average throughput and cell-average throughput with lower blocking probability.
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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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| 8. |
- Zhang, H., et al.
(författare)
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Performance of power control in inter-cell interference coordination for frequency reuse.
- 2010
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Ingår i: Journal of China Universities of Posts and Telecommunications. - 1005-8885. ; 17:1, s. 37-43
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Tidskriftsartikel (refereegranskat)abstract
- In order to mitigate inter-cell interference in 3G evolution systems, A novel inter-cell interference coordination scheme called soft fractional frequency reuse is proposed in this paper, which enables to improve the data rate in cell-edge. On this basis, an inter-cell power control is presented for the inter-cell interference coordination, and the inter-cell balanced SINR among users is established for power allocation, which enables to mitigate inter-cell interference. Especially, the power control is based on a novel exponential kernel equation with faster convergence speed than the traditional arithmetic kernel equations. Numerical results show that the proposed scheme improves the throughput and reduces the blocking rate when compared to the existing power control algorithms.
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