![Polynomial-Time Algorithms for Multirate Anypath
Routing in Wireless Multihop Networks
Abstract—
In this paper, we present a new routing paradigm that generalizes opportunistic
routing for wireless multihop networks. In multirate anypath routing, each node
uses both a set of next-hops and a selected transmission rate to reach a destination.
Using this rate, a packet is broadcast to the nodes in the set, and one of them
forwards the packet on to the destination. To date, there is no theory capable of
jointly optimizing both the set of next-hops and the transmission rate used by each
node. We solve this by introducing two polynomial-time routing algorithms and
provide the proof of their optimality. The proposed algorithms have roughly the
same running time as regular shortest-path algorithms and are therefore suitable for
deployment in routing protocols.
Existing system :
ROUTING in wireless multihop networks is challenging due to the high loss rate
and dynamic quality of wireless links [1]–[4]. Anypath routing1 has been recently
proposed as a way to circumvent these shortcomings by using multiple next-hops
for each destination [5]–[9]. Each packet is broadcast to a forwarding set composed
of several neighbors, and the packet is lost only if none of these neighbors receive
it. Therefore, while the link to a given neighbor is down or performing poorly,
another nearby neighbor may receive the packet and forward it on.
Demerits :
First, loss probabilities increase with higher transmission rates, so a higher bit rate
does not always improve throughput. Second, we must find not only the](https://image.slidesharecdn.com/polynomial-timealgorithmsformultirateanypath-121217235517-phpapp01/85/Polynomial-time-algorithms-for-multirate-anypath-1-320.jpg)
Polynomial time algorithms for multirate anypath
- 1. Polynomial-Time Algorithms for Multirate Anypath Routing in Wireless Multihop Networks Abstract— In this paper, we present a new routing paradigm that generalizes opportunistic routing for wireless multihop networks. In multirate anypath routing, each node uses both a set of next-hops and a selected transmission rate to reach a destination. Using this rate, a packet is broadcast to the nodes in the set, and one of them forwards the packet on to the destination. To date, there is no theory capable of jointly optimizing both the set of next-hops and the transmission rate used by each node. We solve this by introducing two polynomial-time routing algorithms and provide the proof of their optimality. The proposed algorithms have roughly the same running time as regular shortest-path algorithms and are therefore suitable for deployment in routing protocols. Existing system : ROUTING in wireless multihop networks is challenging due to the high loss rate and dynamic quality of wireless links [1]–[4]. Anypath routing1 has been recently proposed as a way to circumvent these shortcomings by using multiple next-hops for each destination [5]–[9]. Each packet is broadcast to a forwarding set composed of several neighbors, and the packet is lost only if none of these neighbors receive it. Therefore, while the link to a given neighbor is down or performing poorly, another nearby neighbor may receive the packet and forward it on. Demerits : First, loss probabilities increase with higher transmission rates, so a higher bit rate does not always improve throughput. Second, we must find not only the
- 2. forwarding set, but also the transmission rate at each hop that jointly minimizes its cost to a destination. For instance, assuming that links , , and achieve their highest throughput at 2, 5.5, and 11 Mbps, respectively, which subset of neighbors should node use to reach the destination, and at which rate should the packet be transmitted? Finally, higher rates have a shorter transmission range, and therefore we have a different connectivity graph for each rate. Lower rates have more neighbors available for inclusion in the forwarding set (i.e., more spatial diversity) and fewer hops between nodes. Higher rates have fewer neighbors available for the forwarding set (i.e., less spatial diversity) and longer routes proposed system : We introduce two polynomial-time routing algorithms to the shortest multirate anypath problem and present a proof of their optimality. Our solution generalizes Dijkstra’s and Bellman–Ford algorithms for the multirate anypath case and are applicable to both link-state and distance-vector routing protocols, respectively. One would expect the running time of such algorithms to be exponential since, with neighbors, we can have up to forwarding sets. However, we show that the proposed algorithms have roughly the same polynomial time as the corresponding shortest-path algorithms and are suitable for implementation at current wireless routers. We also show that our algorithms are optimal even if packet losses at different receivers are not independent .