Multi-Cell Massive MIMO Uplink with Underlay Spectrum Sharing

Hayder Al-Hraishawi, Gayan A. A. Baduge, Hien Quoc Ngo, Erik G. Larsson

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9 Citations (Scopus)
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The achievable rates are investigated for multicell multi-user massive multiple-input multiple-output (MIMO) systems with underlay spectrum sharing. A general pilot sharing scheme and two pilot sequence designs (PSDs) are investigated via fully-shared (PSD-1) and partially-shared (PSD-2) uplink
pilots. The number of simultaneously served primary users (PUs) and secondary users (SUs) in the same time-frequency resource block by the PSD-1 is higher than that of PSD-2. The transmit power constraints for the SUs are derived to mitigate the secondary co-channel interference (CCI) inflicted at the primary
base-station (PBS) subject to a predefined primary interference temperature (PIT). The optimal transmit power control coefficients for the SUs with max-min fairness, and the common achievable rates are derived. The cumulative detrimental effects of channel estimation errors, CCI and intra-cell/inter-cell pilot contamination are investigated. The secondary transmit power constraint and the achievable rates for the perfect channel state information (CSI) case become independent of the PIT when the number of PBS antennas grows unbounded. Therefore, the primary and secondary systems can be operated independent of each other as both intra-cell and inter-cell interference can
be asymptotically mitigated at the massive MIMO PBS and secondary base station (SBS). Nevertheless, the achievable rates and secondary power constraints for the imperfect CSI case with PSD-1 are severely degraded due to the presence of intra-cell and inter-cell pilot contamination. These performance metrics
depend on the PIT even in the asymptotic PBS antenna regime. Hence, the primary and secondary systems can no longer be operated independently for imperfect CSI with PSD-1. However, PSD-2 provides achievable rate gains over PSD-1 despite the requirement of lengthier pilot sequences of the former than that of the latter.
Original languageEnglish
JournalIEEE Transactions on Cognitive Communications and Networking
Early online date25 Oct 2018
Publication statusEarly online date - 25 Oct 2018


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