Subchannel Allocation Scheme for Two-tire Femtocell Networks Based on Q-learning
YANG Xiuqing① CHEN Yu① LI Zhengfu②
①(School of Telecommunication Engineering, Beijing Polytechnic, Beijing 100176, China) ②(School of Information and Communication Engineering, Beijing University of Posts and Telecommunications,Beijing 100876, China)
在Femtocell家庭基站(Femtocell Base Station, FBS)组成的异构网络中，为提升网络的频谱效率，FBS与Macrocell宏基站(Macrocell Base Station, MBS)一般要求是同频部署，然而同频部署会产生同信道干扰。为了实现FBS的大规模部署，降低网络同信道干扰影响变得尤为重要。该文提出一种基于Q-learning的子信道分配方案，既保证大量部署的FBS不会对MBS带来过高的跨层干扰，同时也降低了FBS之间的同层干扰。同时针对FBS稀疏部署和密集部署的场景，分别进行了算法的仿真验证，其仿真结果表明该算法降低了干扰，验证了理论的正确性。
In order to improve the spectrum efficiency in the Femtocell home Base Station (FBS) heterogeneous network, FBS and Macrocell Base Station (MBS) are usually deployed with the same frequency. However, the same frequency deployment will inevitably lead to larger co-channel interference. In order to achieve the large-scale deployment of FBS, reducing the interference of the network with the channel is particularly important. In this paper, a sub channel allocation scheme is propsed based on Q-learning. It can ensure that FBS will not bring high cross-layer interference of MBS, while it reduces the same layer interference between two FBS. The simulation of the algorithm of FBS sparse deployment and dense deployment situation are performed, respectively. Simulation results show that this algorithm reduces the same layer interference and verifies the correctness of the theory.
CHEN W T. Analytic estimation for uplink capacity reduction due to co-channel interference in LTE networks[J]. Wireless Networks, 2014, 21(6): 1775-1782. doi: 10.1007/ s11276-014-0883-y.
[2]
ALADE T, ZHU H, and WANG J. Uplink co-channel interference analysis and cancellation in femtocell based distributed antenna system[C]. IEEE International Conference on Communication (ICC) 2010, Cape Town, South Africa, 2010: 1-5. doi: 10.1109/ICC.2010.5501848.
[3]
MOHSEN M and MAJID G. Uplink scheduling in wireless networks with successive interference cancellation[J]. IEEE Transactions on Mobile Computing, 2014, 13(5): 1132-1144. doi: 10.1109/TMC.2013.56.
[4]
VIKRAM C and JEFFREY J A. Spectrum allocation in tiered cellular networks[J]. IEEE Transactions on Communications, 2009, 57(10): 3059-3068. doi: 10.1109/ TCOMM.2009.10.080529.
[5]
TSIROPOU E E, VAMVAKAS P, PAPAVASSILIOU S, et al Combined power and rate allocation in self-optimized multi-service two-tier femtocell networks[J]. Computer Communications, 2015, 72(12): 38-48. doi: 10.1016/j. comcom.2015.05.012.
DU Xiaoyu, SUN Lijuan, GUO Jian, et al. Coverage optimization algorithm for heterogeneous WSNs[J]. Journal of Electronics & Information Technology, 2014, 36(3): 696-702. doi: 10.3724/SP.J.1146.2013.00730.
[7]
LI Hongjia, XU Xiaodong, HU Dan, et al. Clustering strategy based on graph method and power control for frequency resource management in femtocell and MBS overlaid system[J]. Journal of Communications and Networks, 2011, 13(6): 664-677. doi: 10.1109/JCN.2011.6157483.
[8]
HAN Bin, WANG Wenbo, LI Yong, et al. Investigation of interference margin for the co-existence of MBS and femtocell in orthogonal frequency division multiple access systems[J]. IEEE Systems Journal, 2013, 7(1): 59-67. doi: 10.1109/ JSYST.2012.2223536.
[9]
GUVENC I, JEONG M R, WATANABE F J, et al. A hybrid frequency assignment for femtocells and coverage area analysis for co-channel operation[J]. IEEE Communications Letters, 2008, 12(12): 880-882. doi: 10.1109/LCOMM.2008. 081273.
[10]
ZHENG K, WANG Y, LIN C, et al. Graph-based interference coordination scheme in orthogonal frequency-division multiplexing access femtocell networks[J]. IET Communications, 2011, 5(17): 2533-2541. doi: 10.1049/ iet-com.2011.0134.
[11]
PARK S S, SEO W H, KIM Y J, et al. Beam subset selection strategy for interference reduction in two-tier femtocell networks[J]. IEEE Transactions on Wireless Communications, 2010, 9(11): 3440-3449. doi: 10.1109/ TWC.2010.092410.091171.
ZHANG Haibo, MU Lixiong, CHEN Shanxue, et al. A cluster-based resource allocation in a two-tier OFDMA femtocell networks[J]. Journal of Electronics & Information Technology, 2016, 38(2): 262-268. doi: 10.11999/ JEIT150699.
[13]
CHANG Chihwen. An interference-avoidance code assignment strategy for the hierarchical two-dimensional- spread MC-DS-CDMA system: a prototype of cognitive radio femtocell system[J]. IEEE Transactions on Vehicular Technology, 2012, 61(1): 166-184. doi: 10.1109/TVT.2011. 2173808.
[14]
KANG Xin, LIANG Yingchang, and GARG H K. Distributed power control for spectrum-sharing femtocell networks using stackelberg game[C]. 2011 IEEE International Conference on Communications (ICC), Kyoto, Japan, 2011: 1-5. doi: 10.1109/icc.2011.5962650.
[15]
AHMED M and YOON S G. Dynamic access and power control scheme for interference mitigation in femtocell networks[J]. KSII Transactions on Internet and Information Systems (TIIS), 2015, 9(11): 4331-4346. dio: 10.3837/tiis. 2015.11.004.
[16]
JIN Fan, ZHANG Rong, and HANZO L. Fractional frequency reuse aided twin-layer femtocell networks: Analysis, aesign and optimization[J]. IEEE Transactions on Communications, 2013, 61(5): 2074-2085. doi: 10.1109/ TCOMM.2013.022713.120340.
[17]
JIN Fan, ZHANG Rong, and HANZO L. Frequency- swapping aided femtocells in twin-layer cellular networks relying on fractional frequency reuse[C]. 2012 IEEE Wireless Communications and Networking Conference (WCNC), Paris, France, 2012: 3097-3101. doi: 10.1109/WCNC.2012. 6214337.
[18]
SALATI A H, NASIRI-KENARI M, and SADEGHI P. Distributed subband, rate and power allocation in OFDMA based two-tier femtocell networks using fractional frequency reuse[C]. 2012 IEEE Wireless Communications and Networking Conference (WCNC), Paris, France, 2012: 2626-2630. doi: 10.1109/WCNC.2012.6214243.
[19]
VALCARCE A, LUCAS M, and LOPEZ-PEREZ D. In-cabin downlink cell planning with fractional frequency reuse[C]. 18th European Wireless Conference European Wireless, Poznan, Poland, 2012: 1-5.
[20]
WU Dapeng and NEGI R. Effective capacity: A wireless link model for support of quality of service[J]. IEEE Transactions on Wireless Communications, 2003, 2(4): 630-643. doi: 11.1109/TWC.2003.814353.
[21]
WATKINS C and DAYAN P. Technical note: Q-Learning [J]. Machine Learning, 1992, 8(3/4): 279-292. dio: 10.1023/A: 1022676722315.
