Achievable degrees of freedom region of MIMO relay networks using Detour Schemes

Zewail, Ahmed A.; Nafie, Mohammed; Mohasseb, Yahya; Gamal, Hesham El

doi:10.1109/icc.2014.6883594

Cited by 8 publications

(22 citation statements)

References 11 publications

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“…Remark 2 (Comparison to [11]): In the case with (M 1 , M 2 , M 3 , N ) = (3, 2, 2, 4), the DoF tuple (2, 0, 0, 2, 2, 0) is achievable by Theorem 1. Interestingly, this DoF tuple cannot be achieved using the scheme proposed in [11].…”

Section: Resultsmentioning

confidence: 99%

“…While the converse of the optimal DoF region can indeed be proved easily using the cut-set theorem and genie-message approach, the achievability proof is however very challenging. The conventional method to analyze the achievable DoF in MIMO Y channel in the literature, including [1]- [11], [13], is to first divide all possible antenna configurations into separate cases, and then analyze the achievable DoF case by case. If the achievable DoF coincides with the DoF outer bound, then the optimality is claimed.…”

Section: Introductionmentioning

confidence: 99%

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Optimal Degrees of Freedom Region for the Asymmetric MIMO Y Channel

2016

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Abstract-This letter studies the optimal degrees of freedom (DoF) region for the asymmetric three-user MIMO Y channel with antenna configuration (M1, M2, M3, N ), where Mi is the number of antennas at user i and N is the number of antennas at the relay node. The converse is proved by using the cutset theorem and the genie-message approach. To prove the achievability, we divide the DoF tuples in the outer bound into two cases. For each case, we show that the DoF tuples are achievable by collectively utilizing antenna deactivation, pairwise signal alignment and cyclic signal alignment techniques. This work not only offers a complete characterization of DoF region for the considered channel model, but also provides a new and elegant achievability proof.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimal Degrees of Freedom Region for the Asymmetric MIMO Y Channel

2016

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“…Of the vast amount of literature on beyond one-way relay interference networks, the most closely related to this work are references [5]- [13]. In particular, following the idea of [5], the DoF of several multi-way relay networks were studied in [6]- [8], [11] where they only tackled with networks with special number of antennas, so that the signals carrying every two pairwise symbols can be aligned at the relay.…”

Section: B Prior Workmentioning

confidence: 99%

“…Thus, their results, requiring one-to-one alignment only, are established in a relatively straightforward manner. In [12], [13], the authors studied the DoF of two more general multi-way relay MIMO networks based on, again, one-to-one alignment only, and either their DoF converse or the DoF achievability is not tight in general, thus leaving their exact DoF characterizations [9], based on the idea of inter-pair signal subspace alignment. Compared to [9], this work also needs one-to-many alignment.…”

Section: B Prior Workmentioning

confidence: 99%

Beyond one-way communication: Degrees of freedom of the 4-user relay MIMO Y channel

Wang¹

2014

2014 IEEE International Symposium on Information Theory

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We characterize the degrees of freedom (DoF) of a wireless network consisting of 4 user nodes, each with M antennas, and one N -antenna relay node. In this network, each user sends one independent message to each of the other users, and there are no direct links between any two users, i.e., all communication must pass through the relay node. For this network, we show that the symmetric DoF value per message is given by) normalized by space dimensions, i.e., piecewise linear depending on M, N alternatively. While the information theoretic DoF converse is established for every M, N , the achievability relying on linear signal subspace alignment is established in the spatially-normalized sense in general. The central new insight to emerge from this work is the notion of inter-user signal subspace alignment incorporating the idea of network coding, which is the key to achieve the optimal DoF for multi-way relay interference networks. Moreover, this work also settles the feasibility of linear interference alignment that extends the feasibility framework from one-way to multi-way networks.

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“…[14][15][16][17]). Recently, we applied some of the ideas, developed for the deterministic relay networks, in multiple-input multipleoutput (MIMO) Gaussian set-up in [18].…”

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confidence: 99%

Using network coding to achieve the capacity of deterministic relay networks with relay messages

Zewail

Mohasseb

Nafie

et al. 2016

Wireless Communications

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In this paper, we derive the capacity of the deterministic relay networks with relay messages. We consider a network that consists of five nodes, four of which can only communicate via the fifth one. However, the fifth node is not merely a relay as it may exchange private messages with the other network nodes. First, we develop an upper bound on the capacity region based on the notion of a single-sided genie. In the course of the achievability proof, we also derive the deterministic capacity of a four-user relay network (without private messages at the relay). The capacity achieving schemes use a combination of two network coding techniques: the simple ordering scheme and detour scheme. In the simple ordering scheme, we order the transmitted bits at each user such that the bi-directional messages will be received at the same channel level at the relay, while the basic idea behind the detour scheme is that some parts of the message follow an indirect paths to their respective destinations. This paper, therefore, serves to show that user cooperation and network coding can enhance throughput, even when the users are not directly connected to each other. Finally, we make a conjecture about the capacity region of the general K-node relay network with relay messages.A. Zewail et al.The capacity of deterministic relay networks with relay messages the relay just re-orders the received equations created from the superposition of the transmitted signals on the wireless medium and forwards them. We call this scheme the simple ordering scheme (SOS). Then, from the insights of this work, the authors of [7] used a combination of lattice codes and random Gaussian codes at the source nodes to propose a coding scheme that achieves to within 2 bits per user of the cut-set upper bound on the capacity of the two-pair two-way relay network.Reference [8] studied the two-way X-Channel. First, a new upper bound based on the notion of a single-sided genie was developed, then it was used to characterize the deterministic multicast capacity of their network. To prove the achievability, the authors proposed the idea of Detour Schemes that route some bits intended for a certain receiver via alternative paths when they cannot be accommodated on direct routes. Thereafter, the capacity of the deterministic Y-channel was defined in [9]. Building on this result, the authors investigated the capacity of the Gaussian Ychannel in [10]. Then, we extended these works in [11], by considering a four-user relay network with no direct link, where each user wishes to exchange a number of private messages with the other three users via the relay node. Achievability of the capacity region was demonstrated via two detour schemes (DS), which are different from the ones used in [8] because of the different nature of the multicast network. After that, in [12], we studied the capacity of a three-user relay network where the relay node is interested in exchanging some private messages with the other network users. It was shown that, if all messages emanating from ...

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Achievable degrees of freedom region of MIMO relay networks using Detour Schemes

Cited by 8 publications

References 11 publications

Optimal Degrees of Freedom Region for the Asymmetric MIMO Y Channel

Optimal Degrees of Freedom Region for the Asymmetric MIMO Y Channel

Beyond one-way communication: Degrees of freedom of the 4-user relay MIMO Y channel

Using network coding to achieve the capacity of deterministic relay networks with relay messages

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