Abstract
In this paper, we propose a number of adaptive transmission techniques in order to improve the performance of the secondary link in a spectrum sharing system. We first introduce the concept of minimum-selection maximum ratio transmission (MS-MRT) as an adaptive variation of the existing MRT (MRT) technique. While in MRT all available antennas are used for transmission, MS-MRT uses the minimum subset of antennas verifying both the interference constraint (IC) to the primary user and the bit error rate (BER) requirements. Similar to MRT, MS-MRT assumes that perfect channel state information (CSI) is available at the secondary transmitter (ST), which makes this scheme challenging from a practical point of view. To overcome this challenge, we propose another transmission technique based on orthogonal space-time block codes with transmit antenna selection (TAS). This technique uses the full-rate full-diversity Alamouti scheme in order to maximize the secondary's transmission rate. The performance of these techniques is analyzed in terms of the average spectral efficiency (ASE), average number of transmit antennas, average delay, average BER, and outage performance. In order to give the motivation behind these analytical results, the tradeoffs offered by the proposed schemes are summarized and then demonstrated through several numerical examples.
Original language | English |
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Article number | 2337894 |
Pages (from-to) | 5352-5365 |
Number of pages | 14 |
Journal | IEEE Transactions on Wireless Communications |
Volume | 13 |
Issue number | 10 |
DOIs | |
Publication status | Published - 1 Oct 2014 |
Externally published | Yes |
Keywords
- Adaptive modulation
- Maximum ratio transmission
- Minimum selection
- Performance analysis
- Space-time block codes
- Spectrum sharing
- Transmit beamforming