Linear precoding for the downlink of multiple input single output coexisting wireless systems

2008 ◽  
Vol 2 (6) ◽  
pp. 742 ◽  
Author(s):  
J. Zhou ◽  
J. Thompson
2014 ◽  
Vol 548-549 ◽  
pp. 1363-1367
Author(s):  
Wei Wang ◽  
Yan Hui Lu ◽  
Duan Yang Li ◽  
Shou Yi Yang

This paper proposes a joint linear precoding and power allocation design scheme for multiuser multiple-input multiple-out (MU-MIMO) cognitive radio (CR) systems, where secondary users share the same spectrum with one primary user. The interference power constraint required by the primary user and the multiuser interference generated by secondary users impose negative influence on each secondary user. As a result, it is difficult for secondary users to achieve the ideal information rate. In order to solve the above problem, we respectively adopt Channel Inversion (CI) and Block Diagonalization (BD) for precoding matrices which are set at the transmitter of each secondary user, and then make the system reach a steady state by power allocation. In fact, perfect CSI cannot exist in wireless systems. Therefore, it’s necessary to consider imperfect CSI. Simulation results show BD gains a higher rate for secondary users, but imperfect CSI causes less loss to CI.


2021 ◽  
Vol 3 (2) ◽  
pp. 46-53
Author(s):  
Young B. Choi ◽  
Matthew E. Bunn

With the introduction of the 5th generation of wireless systems and communications (5G) comes new risks and challenges. This paper explores the potential security challenges of 5G communication compared with legacy cellular networks and prior generations of communication standards. This paper defines what 5G is and how it affects our lives on a daily basis. It further discusses the new security features involving different technologies applied to 5G, such as heterogeneous networks, device-to-device communications, massive multiple-input multiple-output, software-defined networks, and the internet of things, including autonomous cars, healthcare, automated manufacturing, and more.


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