| 1. |
- Khanzadi, M Reza, 1983, et al.
(författare)
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A Novel Cognitive Modulation Method Considering the Performance of Primary User
- 2010
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Ingår i: Wireless Advanced (WiAD), 2010 6th Conference on. - 9781424470693 ; , s. 1 - 6
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Konferensbidrag (refereegranskat)abstract
- This paper proposes a new modulation method foran uncoded cognitive transmission (secondary user transmission)in presence of a Primary User (PU) for the AWGN channel.Interference of the PU is assumed to be known at the transmitterof Cognitive User (CU) non-causally. Based on this knowledge,for the design of the modulator and demodulator of the CU,a symbol by symbol approach is studied which can fulfill thecoexistence conditions of the CU and the PU of the band. In thisscheme, the modulator and demodulator of CU are designedjointly by solving an optimization problem to mitigate theinterference of the PU and minimize the symbol error probability(Pe) in CU’s communication link without increasing the symbolerror probability (Pe) of the PU. The proposed method is amodulation approach in a single (complex-valued) dimensionrather than a high dimensional coding scheme. Although thisone-dimensional method is not capacity achieving, we show it stillhas a remarkable performance with low amount of complexity.An implementation algorithm for our modulation method is alsopresented and the performance of this method is evaluated byexperimental results.
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| 2. |
- Tahmasebi Toyserkani, Arash, 1978, et al.
(författare)
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A Complexity Adjustable Scheduling Algorithm for Throughput Maximization in Clusterized TDMA Networks
- 2010
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. - 9781424425198
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Konferensbidrag (refereegranskat)abstract
- We consider clustered wireless networks, wheretransceivers in a cluster use a time-slotted mechanism (TDMA) to access a wireless channel that is shared among several clusters.Earlier work has demonstrated that a significant increase innetwork throughput can be achieved if all the schedules areoptimized jointly. However, a drawback of this approach is the prohibitive level of computational complexity is required when a network with a large number of clusters and time-slots is to be scheduled. In this paper, we propose a modification to our previously proposed algorithm which allows for the complexityto be adjusted to the available processing power, provided some minimum processing power is available. This is achieved by carefully reducing the number of interfering clusters considered when scheduling a cluster. In addition, we propose and evaluatetwo heuristic methods of discarding the less significant clusters.While the optimality of the obtained schedule is not proven, our results demonstrate that large gains are consistently attainable.
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