Delay reduction in multi-hop device-to-device communication using network coding

Abstract

This paper considers the problem of reducing the broadcast delay of wireless networks using instantly decodable network coding (IDNC) based device-to-device (D2D) communications. In D2D-enabled networks, devices help hasten the recovery of the lost packets of devices in their transmission range by sending network coded packets. To solve the problem, the different events occurring at each device are identified so as to derive an expression for the probability distribution of the decoding delay. The joint optimization problem over the set of transmitting devices and the packet combinations of each is formulated. Due to the high complexity of finding the optimal solution, this paper focuses on cooperation without interference between the transmitting users. The optimal solution, in such interference-less scenario, is expressed using a graph theory approach by introducing the cooperation graph. Extensive simulations compare the decoding delay experienced in the Point to Multi-Point (PMP), the fully connected D2D (FC-D2D) and the more practical partially connected D2D (PC-D2D) configurations and suggest that the PC-D2D outperforms the FC-D2D in all situations and provides an enormous gain for poorly connected networks.

Instantly Decodable Network Coding: From Centralized to Device-to-Device Communications

“…Not only they should use solely the packets they hold but also they can target only the users in their transmission range. For each user i in the network, the authors in [179] proposes a graph formulation ,similar to the local G-IDNC graphs, that is able to generate coding combinations only from the packets it holds and intended to users in its transmission range. As we will explain in the next section, the transmission range of users changes with the set of the transmitting users since, depending on this set, a subset of users will be in interference and cannot be targeted by any other user.…”

“…Douik et al [179] investigated the problem of minimizing the decoding delay in CDE enabled PC-D2D network. After defining the cooperative decoding delay, the authors identified the expression of the decoding delay increment of all users in the network in order to formulate the cooperative decoding delay minimization problem.…”

Decoding-Delay-Controlled Completion Time Reduction in Instantly Decodable Network Coding

“…In other words, once a clique is chosen according to (13) among the vertices representing users in the highly critical set P(t), there may exist vertices belonging to other users that can form an even bigger clique. Thus, adding these vertices to the clique and serving this user will benefit them without affecting the IDNC constraint for the users belonging to P(t).…”

“…The paper considers that algorithm whose steps can be found in [33]. This section suggests defining the objective function φ so as to both minimize the critical criterion (13) and to improve the approximation in (9) using a same method like the one in the previous heuristic.…”

“…Though both proved to be NP-hard parameters to minimize, many heuristics have been developed to solve them in many scenarios, e.g., references [11]- [13] study the decoding delay reduction and references [14]- [16] the completion time minimization in a device-todevice communication enabled network. In fact, it can be readily inferred from [9] and [10] that the policies derived so far to optimize one usually degrades the other.…”