Spectrum sensing and power/rate control in CDMA cognitive radio networks
Spectrum sensing and power/rate control in CDMA cognitive radio networks
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DOI：
10.1002/dac.1258
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发表时间：
2012-02
影响因子：
2.1
通讯作者：
S. Ghavami;B. Abolhassani
中科院分区：
文献类型：
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作者：
S. Ghavami;B. Abolhassani
本文提出了一种用于次级用户（S-用户）或认知无线电的频谱感知和功率/速率控制的两阶段算法。在第一阶段中，主基站（P-BS），其意识到主活跃用户（P-user）的数量和数据速率，广播其小区的使用容量百分比（UCP）。由于仅知道UCP不足以保证（P用户和S用户的）总负载小于最大允许负载，因此S用户必须测量从P用户和其他S用户接收的总干扰。在这个方向上，使用UCP和S用户或辅基站（S-BS）从P用户和S用户接收的干扰的测量，我们在数学上推导出用于发布数据传输许可的等式，如果它被保持，则算法的第二阶段：发射功率/速率控制开始。在该阶段中，S用户和S-BS寻找发射功率电平和传输速率的可行值。如果存在可行的值，则它以这些可行的发射功率和速率开始其发射。由于S用户的位置和信道条件都随时间变化，因此整个算法周期性地迭代，其周期快于信道的相干时间。此外，我们考虑上述系统的下行链路与相邻S用户之间的合作以克服衰落信道，并调查发布数据传输许可的可靠性的改进程度。同时，我们考虑了S-BS中具有多个天线的系统的上行链路，以研究在空间相关和独立衰落信道上相同参数的改进。利用计算机模拟验证了理论分析。理论分析和计算机仿真结果表明，该算法在平坦Nakagami-m衰落信道（m = 1）中，信噪比为-5dB时，即使在相关衰落信道中也能保持良好的性能。我们还解决了在仅在S-BS中使用多个天线的情况下在上行链路中发布数据传输许可的可靠性的改进。版权所有© 2011约翰威利父子有限公司.
In this paper, a two‐phase algorithm for the spectrum sensing and power/rate control of a secondary user (S‐user) or cognitive radio is proposed. In the first phase, the primary base station (P‐BS), which is conscious of both the number and the data rate of primary active users (P‐user), broadcasts theitusage capacity percentage (UCP) of its cell. Since knowing only the UCP is not enough to guarantee that the total load (of P‐users and S‐users) is less than a maximum permissible load, the S‐user must measure the total interference received from both the P‐users and other S‐users. In this direction, using both the UCP and measurement of the interference received from the P‐users and the S‐users by the S‐user or secondary base station (S‐BS), we mathematically derive an equation for issuing data transmission permission, which if it is held then the second phase of the algorithm: the transmit power/rate control starts. In this phase, the S‐user and the S‐BS look for feasible values for the transmit power level and transmission rate. If there are feasible values, it starts its transmission at these feasible transmit power and rate. Since both the location of the S‐user and the channel condition vary in time, the whole algorithm is iterated periodically with a period faster than the coherence time of the channel. Furthermore, we consider the down link of the above system with cooperation among neighboring S‐users to overcome fading channels and we investigate the amount of improvement in the reliability of the issuing data transmission permission. As well, we consider the uplink of the system with multiple antennas in the S‐BS to investigate the improvement in the same parameter over spatially correlated and independent fading channels. Theoretical analysis is validated using computer simulations. Both theoretical analysis and computer simulations show that the proposed cooperative spectrum sensing algorithm performs properly at SNR = −5dB in flat Nakagami‐m fading channels with m = 1 even in correlated fading channels. We also address the improvement of the reliability of the issuing data transmission permission in the uplink in case of using multiple antennas only in the S‐BS. Copyright © 2011 John Wiley & Sons, Ltd.