A Feasible Distance Aligned Structure for Underwater Acoustic X Networks with Two Receivers

To obtain a full picture of potential applications for propagation-delay based X channels, it is important to obtain all feasible schemes of cyclic interference alignment including the encoder, channel instance, and decoder. However, when the dimension goes larger, theoretical analysis about this issue will become tedious and even impossible. In this letter, we propose a computer-aided solution by searching the channel space and the scheduling space, which can find all feasible schemes in details. Examples are given for some typical X channels. Computational complexity is further analyzed.

Section: Introductionmentioning

confidence: 99%

A Computer-Aided Solution to Find All Feasible Schemes of Cyclic Interference Alignment for Propagation-Delay Based X Channels

Zhou

et al. 2023

“…In [6], we propose the implement of prefect IA based on PD with a DoF of 2K/(K + 1) for K × 2 X channel and give the corresponding feasibility condition in Euclidean space. Further detail of node placements is demonstrated in [7].…”

Section: Introductionmentioning

confidence: 99%

Propagation-Delay Based Cyclic Interference Alignment with One Extra Time-Slot for Three-User X Channel

Liu

Wang

Jiang

et al. 2019

Self Cite

For the three-user X channel, its degree of freedom (DoF) 9/5 has been shown achievable theoretically through asymptotic model with infinite resources, which is impractical. In this article, we explore the propagation delay (PD) feature among different links to maximize the achievable DoF with the minimum cost. Since perfect interference alignment (IA) is impossible for 9 messages within 5 time-slots, at least one extra timeslot should be utilized. By the cyclic polynomial approach, we propose a scheme with the maximum achievable DoF of 5/3 for 10 messages within 6 time-slots. Feasibility conditions in the Euclidean space are also deduced, which demonstrates a quite wide range of node arrangements.

“…In [9], perfect PD-based cyclic IA was first studied for the 2 × 2 XC and K-user IC to achieve the DoF of 4/3 and K/2, respectively. Recently, we investigate the perfect IA based on proper PD structure for K × 2 XC in [10], while further node placement analysis is given in [11]. Moreover, for the three-user X channel, since perfect IA is impossible [12], we propose a feasible scheme with one extra time slot to achieve the maximum DoF by allowing one more mes-sage based on the cyclic IA approach [13].…”

Section: Introductionmentioning

confidence: 99%

A General Perfect Cyclic Interference Alignment by Propagation Delay for Arbitrary X Channels with Two Receivers

Liu

Jiang

et al. 2019

Self Cite

Interference alignment (IA) in temporal domain is important in the case of single-antenna vehicle communications. In this paper, perfect cyclic IA based on propagation delay is extended to the K × 2 X channels with two receivers and arbitrary transmitters K ≥ 2, which achieves the maximal multiplexing gain by obtaining the theoretical degree of freedom of 2K/(K + 1). We deduce the alignment and separability conditions, and propose a general scheme which is flexible in setting the index of time-slot for IA at the receiver side. Furthermore, the feasibility of the proposed scheme in the two-/three-Euclidean space is analyzed and demonstrated.