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An improved cooperative spectrum sensing of femtocells with hybrid TDD access scheme in massive MIMO system
Author(s) -
Bai Zhiquan,
Gao Peng,
Su Yingyan,
Han Tao,
Kwak Kyungsup,
Park Daeyoung
Publication year - 2017
Publication title -
international journal of communication systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.344
H-Index - 49
eISSN - 1099-1131
pISSN - 1074-5351
DOI - 10.1002/dac.3199
Subject(s) - macrocell , computer science , mimo , base station , femtocell , duplex (building) , spectral efficiency , throughput , computer network , cognitive radio , electronic engineering , channel (broadcasting) , wireless , telecommunications , engineering , dna , biology , genetics
Summary To improve the sensing performance and achieve higher throughput of the femtocells (FCs) while alleviating the influence to the macrocell in the cognitive massive multiple‐input and multiple‐output system (MIMO), we propose in this paper a hybrid time‐division duplex (TDD) access scheme of the FCs with confidence factor–based weighted cooperative spectrum sensing (CSS). A first, we present an efficient hybrid TDD access scheme for better spectrum reuse of the FCs based on the typical TDD and reversed TDD schemes. Furthermore, confidence factor–based weighted CSS has been used for better spectrum sensing and interference alleviation. In the cognitive massive MIMO system, FC base stations will form dynamical clustering based on the channel conditions, sense the spectrum through cooperative scheme, and decide whether to access the spectrum or not. After information exchange within each FC cluster, the FC base stations can obtain and update their confidence factors and weight factors based on the sensing results and reliability. Numerical results and theoretical analysis show that the proposed scheme can get more accurate sensing results, increase the throughput and the spectrum access opportunity of the FCs, and efficiently alleviate the interference to the macrocell tier.