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Current and future mobile network access technologies increasingly rely on multiantenna transmission techniques and on cell miniaturization to achieve orders-of-magnitude gains in capacity. In this paper, we propose and evaluate the idea of multiuser multiple-input–multiple-input-based (MU-MIMO) cell reassignments. Dense small-cell deployments make it possible to pair user equipment units (UEs), which were originally assigned to different cells, enabling multiuser MIMO (MU-MIMO) and resulting in performance improvements to both UEs. We discuss how such pairings can be accomplished, and we assess the potential gains in the resulting spectral efficiency and MU-MIMO usage. These are assessed through both discussion of performance bounds and detailed system-level simulation in a realistic outdoor small-cell scenario. [ABSTRACT FROM PUBLISHER]

In this paper, an efficient FPGA implementation of a 4×4 Space-Time Block Coding (STBC) combiner for MIMO-OFDM software radio receivers is considered. The proposed combiner is based on a low-complexity algorithm which reduces the interference due to the Quasi-Orthogonality of the STBC decoding. In the literature, feedback techniques have been proposed to solve this problem. However, the algorithm introduced in this paper has been conceived in order to avoid the transmission feedback, by estimating the interference factors and removing them. The proposed algorithm exhibits a low computational complexity and complies with the requirements of HW feasibility, considering the execution time/area occupation trade-off. [ABSTRACT FROM AUTHOR]

Current wireless access networks are able to provide relatively low data rates when compared with wired access. To extend the access to high-data-rate services to wireless users, the International Telecommunication Union (ITU) established new requirements for future wireless communication technologies of up to 100 Mb/s under high-mobility conditions and 1 Gb/s in low mobility. The low mobility goal can only be achieved through the use of highly optimized local area access networks operating at low range and low transmission power. The efficient sharing of radio resources among local area cells will be very difficult to achieve with a traditional network planning/dimensioning approach due to their intrinsic uncoordinated deployment characteristic. Cognitive radio (CR)-based networking methodologies are considered as the most promising solutions for such radio-resource-sharing problems, also enabling unlicensed/open spectrum operations. In this paper, a game-theory-inspired scalable algorithm for intercell dynamic spectrum access (IC-DSA) is introduced to enable distributed resource allocation in CR environments. Here, the new CR-based cell is called "cognitive cell (C-cell)," and it is the minimal entity that allocates a resource set. The simulation results demonstrate the effectiveness of the proposed spectrum-sharing approach. This solution achieves a better overall performance in several load and interference scenarios in terms of both outage and average capacity when compared with fixed-frequency-reuse cases. [ABSTRACT FROM AUTHOR]