| 1. |
- Blad, Anton, et al.
(författare)
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Spectrum Sensing of OFDM Signals in the Presence of CFO : New Algorithms and Empirical Evaluation Using USRP
- 2012
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Ingår i: Proceedings of the 13th IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC). - : IEEE. - 9781467309691 - 9781467309707 - 9781467309714 ; , s. 159-163
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Konferensbidrag (refereegranskat)abstract
- In this work, we consider spectrum sensing of OFDM signals. We deal withthe inevitable problem of a carrier frequency offset, and propose modificationsto some state-of-the-art detectors to cope with that. Moreover, the (modified)detectors are implemented using GNU radio and USRP, and evaluated over aphysical radio channel. Measurements show that all of the evaluated detectorsperform quite well, and the preferred choice of detector depends on thedetection requirements and the radio environment.
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| 2. |
- Lindblom, Johannes, 1983-, et al.
(författare)
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Does non-orthogonal spectrum sharing in the same cell improve the sum-rate of wireless operators?
- 2012
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Ingår i: Proceedings of the 13th IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC). - 9781467309707 - 9781467309691 - 9781467309714 ; , s. 6-10
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Konferensbidrag (refereegranskat)abstract
- We study non-orthogonal spectrum sharing to determine under what circumstances operators can gain by such sharing. To model the spectrum sharing, we use the multiple-input single-output (MISO) interference channel (IC) assuming that the operators transmit in the same band. For the baseline scenario of no sharing, we use the MISO broadcast channel (BC) assuming that the operators transmit in disjunct bands. For both the IC and BC, we give achievable (lower) and upper bounds on the maximum sum-rate. While these bounds are well-known we also propose a new fast algorithm for finding a lower bound on the sum-rate of the BC using linear beamforming.We use the bounds to numerically evaluate the potential gain of non-orthogonal spectrum sharing. In this study we assume that the operators efficiently utilize all their spatial degrees of freedom. We will see that the gains from spectrum sharing under these circumstances are limited.
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| 3. |
- Mehrpouyan, Hani, 1981, et al.
(författare)
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Time-varying phase noise and channel estimation in MIMO systems
- 2012
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Ingår i: IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC. - 9781467309707 ; , s. 560-564
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Konferensbidrag (refereegranskat)abstract
- Performance of high speed communication systems is negatively affected by oscillator phase noise (PN). In this paper joint estimation of channel gains and Wiener PN in multi-input multi-output (MIMO) systems is analyzed. The signal model for the estimation problem is outlined in detail. In order to reduce overhead, a low complexity data-aided least-squares (LS) estimator for jointly obtaining the channel gains and PN parameters is derived. In order to track PN processes over a frame, a new decision-directed extended Kalman filter (EKF) is proposed. Numerical results show that the proposed LS and EKF based PN estimator performances are close to the CRLB and simulation results indicate that by employing the proposed estimators the bit-error rate (BER) performance of a MIMO system can be significantly improved in the presence of PN.
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