DocumentCode :
54415
Title :
Aligning Guard Zones of Massive MIMO in Cognitive Femtocell Networks
Author :
Yanchun Li ; Guangxi Zhu ; Xiaojiang Du
Author_Institution :
Huazhong Univ. of Sci. & Technol., Wuhan, China
Volume :
18
Issue :
2
fYear :
2014
fDate :
Feb-14
Firstpage :
229
Lastpage :
232
Abstract :
Femtocells may coexist with macrocells in the same band and significantly improve the spatial reuse (SR) of spectrum. To avoid high interference to the scheduled macrocell users (MUs), femtocell base stations (BSs) sense and access the channel opportunistically. When massive MIMO is deployed at macrocell BS, we find that this cognitive behavior forms too many guard zones scattered over macrocell´s coverage area and seriously degrades spatial reuse efficiency. In this work, we consider not only the inter-user channel orthogonality, but also geographic locations for massive MIMO user scheduling in cognitive two-tier networks. We propose to choose MUs not far from each other as receivers of the macrocell´s downlink spatial multiplexing streams, such that guard zones can be aligned spatially and more SR opportunities can be provided to femtocells. Simulations show that our scheme can significantly improve femto-tier throughput while only slightly sacrificing macro-tier throughput.
Keywords :
MIMO communication; cognitive radio; femtocellular radio; interference suppression; radio direction-finding; radio receivers; radio spectrum management; radiofrequency interference; scheduling; signal detection; space division multiplexing; wireless channels; BS; MU; SR; cognitive femtocell network; cognitive two-tier network; femtocell base station; geographic locations; guard zone scattering alignment; interference; interuser channel; macrocell downlink spatial multiplexing stream; macrocell user; massive MIMO user scheduling; radio receiver; spatial spectrum reuse improvement; Arrays; Fading; Interference; MIMO; Macrocell networks; Multiuser detection; Throughput; Femtocell; massive MIMO; scheduling;
fLanguage :
English
Journal_Title :
Communications Letters, IEEE
Publisher :
ieee
ISSN :
1089-7798
Type :
jour
DOI :
10.1109/LCOMM.2013.123113.131913
Filename :
6708133
Link To Document :
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