2014/07/31 by Ahmed Wagdy, Amr El‐Keyi, Wagdy, Ahmed +6
Computer Science · Engineering · Mathematics · #Advanced MIMO Systems Optimization #Cooperative Communication and Network Coding #FOS: Computer and information sciences #Information Theory (cs.IT) #Wireless Communication Security Techniques #cs.IT #math.IT
paper · pdf · doi:10.48550/arxiv.1407.8348
It is only a draft insha'Allah. arXiv admin note: substantial text overlap with arXiv:1404.6348
arxiv created 2014/07/31 · openalex publication_date 2014/07/31 · arxiv updated 2014/08/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this paper, we establish the degrees of freedom (DoF) of the two-user single input single output (SISO) X-channel with alternating channel state information at the transmitters (CSIT). Three cases are considered for the availability of CSIT; perfect, delayed and no-CSIT. Each state is associated with a fraction of time denoted by λP, λD and λN , respectively. We provide new results for DoF of the two-user SISO X-channel when the available CSIT alternates between these three cases under a certain distribution Λ(λP, λD, λN ). Specifically, we show that the X-channel with alternating CSIT for Λ(1/8, 3/8, 1/2) can achieve 5/4 DoF. The interesting thing about 5/4 is that it represents a position of compromise or a middle ground between the channel knowledge that transmitters need to steer interference and the degrees of freedom that the network can achieve. Moreover, 5/4 is strictly greater than 6/5 which is the upper bound for the X-channel with fixed delayed CSIT.