We present Greedy Perimeter Stateless Routing (GPSR), a novel routing protocol for wireless datagram networks that uses the positions of routers and a packet's destination to make packet forwarding decisions. GPSR makes greedy forwarding decisions using only information about a router's immediate neighbors in the network topology. When a packet reaches a region where greedy forwarding is impossible, the algorithm recovers by routing around the perimeter of the region. By keeping state only about the local topology, GPSR scales better in per-router state than shortest-path and ad-hoc routing protocols as the number of network destinations increases. Under mobility's frequent topology changes, GPSR can use local topology information to find correct new routes quickly. We describe the GPSR protocol, and use extensive simulation of mobile wireless networks to compare its performance with that of Dynamic Source Routing. Our simulations demonstrate GPSR's scalability on densely deployed wireless networks.

/pdf/gpsr-greedy-perimeter-stateless-routing-for-wireless-59gz21qf8y.pdf

GPSR: greedy perimeter stateless routing for wireless networks

https://www.cs.montana.edu/courses/csci566/Ref/CR-Survey.pdf

NeXt generation/dynamic spectrum access/cognitive radio wireless networks: a survey

Advances in processor, memory and radio technology will enable small and cheap nodes capable of sensing, communication and computation. Networks of such nodes can coordinate to perform distributed sensing of environmental phenomena. In this paper, we explore the directed diffusion paradigm for such coordination. Directed diffusion is datacentric in that all communication is for named data. All nodes in a directed diffusion-based network are application-aware. This enables diffusion to achieve energy savings by selecting empirically good paths and by caching and processing data in-network. We explore and evaluate the use of directed diffusion for a simple remote-surveillance sensor network.

/pdf/directed-diffusion-a-scalable-and-robust-communication-4tsx5vxsas.pdf

Directed diffusion: a scalable and robust communication paradigm for sensor networks

"A Survey of Mobility Models for Ad Hoc Network Research," Wireless Comm. & Mobile Computing (WCMC) : Special issue on Mobile Ad Hoc Networking : Research

In the performance evaluation of a protocol for an ad hoc network, the protocol should be tested under realistic conditions including, but not limited to, a sensible transmission range, limited buffer space for the storage of messages, representative data traffic models, and realistic movements of the mobile users (i.e., a mobility model). This paper is a survey of mobility models that are used in the simulations of ad hoc networks. We describe several mobility models that represent mobile nodes whose movements are independent of each other (i.e., entity mobility models) and several mobility models that represent mobile nodes whose movements are dependent on each other (i.e., group mobility models). The goal of this paper is to present a number of mobility models in order to offer researchers more informed choices when they are deciding upon a mobility model to use in their performance evaluations. Lastly, we present simulation results that illustrate the importance of choosing a mobility model in the simulation of an ad hoc network protocol. Specifically, we illustrate how the performance results of an ad hoc network protocol drastically change as a result of changing the mobility model simulated.

/pdf/a-survey-of-mobility-models-for-ad-hoc-network-research-ygkxat400x.pdf

A survey of mobility models for ad hoc network research

In our previous work [1] and [2] we showed by example that linear network coding cannot achieve secure network capacity for error detection. To the best of our knowledge, it was the first work that identified the insufficiency of linear network codes in achieving secure capacity, even for unicast. Some recent works [3], [4] also discovered (independently) the necessity of non-linear network codes to achieve secure capacity.

/pdf/short-notes-on-communication-with-byzantine-node-failures-4b5fqdflwy.pdf

Short Notes on Communication with Byzantine Node Failures: Part I

In this paper, we consider the problem of maximizing the throughput of Byzantine agreement, for two cases: i. com- munication link's capacity is fixed; and ii. the sum capacity of all links in the system is fixed. Byzantine agreement is a classical problem in distributed computing, with initial so- lutions presented in the seminal work of Pease, Shostak and Lamport. The notion of throughput here is similar to that used in the networking/communications literature on uni- cast or multicast traffic. In case i, we characterize the max- imum achievable agreement throughput in four-node net- works. In case ii, we identify sufficient condition for achiev- ing agreement throughput R.

/pdf/s-3-short-paper-capacity-of-byzantine-agreement-summary-of-1ufp3x65fh.pdf

S-3 Short Paper / Capacity of Byzantine Agreement: Summary of Recent Results ∗

Multiparty Equality and Byzantine Broadcast using Random Linear Codes in Point-to-Point Networks

In this work, we introduce the problem of reading and writing to a system of high storage passive RFID tags. We consider design goals, based on motivating applications. We consider access protocols and provide preliminary performance results. Future work includes defining more detailed access protocols (and in which scenarios they are applicable). We also plan to evaluate these protocols more extensively through simulations and experiments using RFID hardware.

Efficient Access Protocols for High Storage RFID

In wireless LANs, MAC protocols perform one of the most important tasks: efficiently sharing the limited bandwidth among the contending stations. In IEEE 802.11, Distributed Coordination Function (DCF) is used as a default MAC protocol. Despite its wide acceptance, it has two major downsides: i) Channel idle time and ii) Collision overheads. Besides, the use of the explicit ack frames incurs extra overhead due to the preamble, packet headers etc. This paper presents an optimized version of the Overheard-ACK (O-ACK) protocol (presented in [2]) which incorporates piggybacking, packet overhearing and token based scheduling to significantly reduce the overheads. The previous version of O-ACK creates chains of transmissions, where consecutive transmissions are separated by SIFS interval, which increases the throughput. But on the downside, as two adjacent transmissions are separated by only SIFS idle time, a newly arrived station cannot start transmission. Our current version of O-ACK ensures higher throughput and fairness in multiple AP scenario by continuously adapting the chain creation process based on the surrounding environment. Our NS-2 based simulation results confirm that this protocol significantly outperforms the DCF protocol.

Nitin H. Vaidya

Papers

Short Notes on Communication with Byzantine Node Failures: Part I

S-3 Short Paper / Capacity of Byzantine Agreement: Summary of Recent Results ∗

Multiparty Equality and Byzantine Broadcast using Random Linear Codes in Point-to-Point Networks

Efficient Access Protocols for High Storage RFID

Optimized O-ACK: An adaptive wireless MAC protocol for multiple access points