Parallel Opportunistic Routing in Wireless Networks

We study benefits of opportunistic routing in a large wireless ad hoc network by examining how the power, delay, and total throughput scale as the number of source- destination pairs increases up to the operating maximum. Our opportunistic routing is novel in a sense that it is massively parallel, i.e., it is performed by many nodes simultaneously to maximize the opportunistic gain while controlling the inter-user interference. The scaling behavior of conventional multi-hop transmission that does not employ opportunistic routing is also examined for comparison. Our results indicate that our opportunistic routing can exhibit a net improvement in overall power--delay trade-off over the conventional routing by providing up to a logarithmic boost in the scaling law. Such a gain is possible since the receivers can tolerate more interference due to the increased received signal power provided by the multi-user diversity gain, which means that having more simultaneous transmissions is possible.Comment: 18 pages, 7 figures, Under Review for Possible Publication in IEEE Transactions on Information Theor

Social-Aware Forwarding Improves Routing Performance in Pocket Switched Networks

Several social-aware forwarding strategies have been recently introduced in opportunistic networks, and proved effective in considerably in- creasing routing performance through extensive simulation studies based on real-world data. However, this performance improvement comes at the expense of storing a considerable amount of state information (e.g, history of past encounters) at the nodes. Hence, whether the benefits on routing performance comes directly from the social-aware forwarding mechanism, or indirectly by the fact state information is exploited is not clear. Thus, the question of whether social-aware forwarding by itself is effective in improving opportunistic network routing performance remained unaddressed so far. In this paper, we give a first, positive answer to the above question, by investigating the expected message delivery time as the size of the net- work grows larger

Social-Aware Forwarding Improves Routing Performance in Pocket Switched Networks

Several social-aware forwarding strategies have been recently intro- duced in opportunistic networks, and proved eective in considerably in- creasing routing performance through extensive simulation studies based on real-world data. However, this performance improvement comes at the expense of storing a considerable amount of state information (e.g, history of past encounters) at the nodes. Hence, whether the benets on routing performance comes directly from the social-aware forwarding mechanism, or indirectly by the fact state information is exploited is not clear. Thus, the question of whether social-aware forwarding by itself is eective in im- proving opportunistic network routing performance remained unaddressed so far. In this paper, we give a rst, positive answer to the above question, by investigating the expected message delivery time as the size of the net- work grows larger. In order to make a fair comparison with stateless, social oblivious forwarding mechanisms such as BinarySW, we introduce a simple stateless, social-aware forwarding mechanism exploiting a notion of similarity between individual interests. We then compare the asymp- totic performance of interest-based forwarding with that of BinarySW under two mobility scenarios, modeling situations in which node pairwise meeting rates are independent of or correlated to the similarity of their in- terests. We formally prove that, while asymptotic expected delivery time of BinarySW is highly dependent on the underlying mobility model, with unbounded expected delivery time in presence of correlated mobility, this is not the case with interest-based forwarding, which provides bounded expected delivery time with both mobility models. Thus, our ndings for- mally prove that social-aware forwarding, even when not exploiting state information, has the potential to considerably improve routing perfor- mance in opportunistic networks over traditional forwarding mechanisms

Low Power, Low Delay: Opportunistic Routing meets Duty Cycling

Traditionally, routing in wireless sensor networks consists of two steps: First, the routing protocol selects a next hop, and, second, the MAC protocol waits for the intended destination to wake up and receive the data. This design makes it difficult to adapt to link dynamics and introduces delays while waiting for the next hop to wake up. In this paper we introduce ORW, a practical opportunistic routing scheme for wireless sensor networks. In a dutycycled setting, packets are addressed to sets of potential receivers and forwarded by the neighbor that wakes up first and successfully receives the packet. This reduces delay and energy consumption by utilizing all neighbors as potential forwarders. Furthermore, this increases resilience to wireless link dynamics by exploiting spatial diversity. Our results show that ORW reduces radio duty-cycles on average by 50% (up to 90% on individual nodes) and delays by 30% to 90% when compared to the state of the art