Molecular Communication Using Brownian Motion with Drift

Inspired by biological communication systems, molecular communication has been proposed as a viable scheme to communicate between nano-sized devices separated by a very short distance. Here, molecules are released by the transmitter into the medium, which are then sensed by the receiver. This paper develops a preliminary version of such a communication system focusing on the release of either one or two molecules into a fluid medium with drift. We analyze the mutual information between transmitter and the receiver when information is encoded in the time of release of the molecule. Simplifying assumptions are required in order to calculate the mutual information, and theoretical results are provided to show that these calculations are upper bounds on the true mutual information. Furthermore, optimized degree distributions are provided, which suggest transmission strategies for a variety of drift velocities.Comment: 20 pages, 7 figures, Accepted for publication in IEEE Trans. on NanoBioscienc

Delay-Privacy Tradeoff in the Design of Scheduling Policies

Traditionally, scheduling policies have been optimized to perform well on metrics, such as throughput, delay, and fairness. In the context of shared event schedulers, where a common processor is shared among multiple users, one also has to consider the privacy offered by the scheduling policy. The privacy offered by a scheduling policy measures how much information about the usage pattern of one user of the system can be learned by another as a consequence of sharing the scheduler. We introduced an estimation error-based metric to quantify this privacy. We showed that the most commonly deployed scheduling policy, the first-come-first-served offers very little privacy to its users. We also proposed a parametric nonwork conserving policy, which traded off delay for improved privacy. In this paper, we ask the question, is a tradeoff between delay and privacy fundamental to the design to scheduling policies? In particular, is there a work conserving, possibly randomized, and scheduling policy that scores high on the privacy metric? Answering the first question, we show that there does exist a fundamental limit on the privacy performance of a work-conserving scheduling policy. We quantify this limit. Furthermore, answering the second question, we demonstrate that the round-robin scheduling policy (deterministic policy) is privacy optimal within the class of work-conserving policies

Using full duplex relaying in device-to-device (D2D) based wireless multicast services: a two-user case

D2D communication has been proposed as an important supplement to the existing centralized cellular networks which allows two physically adjacent cellular user equipments (UEs) to communicate directly. This paper concerns using D2D to improve wireless multicast services in cellular networks. Specially, we consider a D2D transmitter UE can act as a full-duplex (FD) relay to assist a cellular multicast from a base station (BS) to a group of two UEs. And a new scheme which allows an intra-cell D2D retransmission to underlay a cellular multicast is proposed. Under the constraint of the minimum signal-to-interference-and-noise ratio (SINR) required by each of the receiver UEs, the aim of the scheme is to select the best UE in a multicast group to perform the D2D retransmission with the serving BS. Thus, the aggregate transmit power consumed at the BS and at the selected UE can be minimized. The numerical results show that the proposed scheme outperforms traditional cellular multicast scheme as it consumes less transmit power to achieve the same SINR target at the receiver UEs

Incentive Mechanism for Multiuser Cooperative Relaying in Wireless Ad Hoc Networks: A Resource-Exchange Based Approach

This paper studies the resource allocation (RA) and the relay selection (RS) problems in cooperative relaying (CR) based multiuser ad hoc networks, and a multiuser cooperative game is proposed to stimulate selfish user nodes to participate in the CR. The novelty of the game scheme lies in that it takes explicit count of that a wireless user can act as a data-source as well as a potential relay for other users. Consider a user has the selfish incentive to consume his/her spectrum resource solely to maximize his/her own data-rate and the selection cooperation (SC) rule which restricts relaying for a user to only one relay is explicitly imposed. To stimulate user nodes to share their energy and spectrum resource efficiently in the Pareto optimal sense, first, we formulate the RA problem for multiuser CR as a bargaining game. By solving the Nash bargaining solution of the game, Pareto optimal RA for cooperative partners can be achieved. Next, to implement the SC-rule imposed RS, a simple heuristic is proposed with the main method being to maintain the long-term priority fairness for cooperative partner selection for each selfish user. The proposed RS with RA (RS-RA) algorithm has a low computational complexity of O (K 2), where K is the number of users in a network. Simulation results demonstrate the system efficiency and fairness properties of the proposed bargaining game theoretic RS-RA scheme. © 2013 Springer Science+Business Media New York