A Proximity-based Routing Protocol for Wireless Multi-hop Networks Tokuda Lab. Keio Univ. Masato Saito

Introduction About Ad hoc Network Current Problem DoCoMo成果発表 Introduction About Ad hoc Network Current Problem Solution: Optimized Re-Routing (OR2) Main Evaluation Experiments Simulation Conclusion and Future Work

Mobile Ad Hoc Networks → Formed by wireless hosts which may be mobile Introduction DoCoMo成果発表 Mobile Ad Hoc Networks Formed by wireless hosts which may be mobile Without (necessarily) using a pre-existing infrastructure Routes between nodes may potentially contain multiple hops Node Mobility causes route changes → Ease of deployment, Speed of deployment, Decreased dependence on infrastructure

Many Applications Personal area networking Military environments DoCoMo成果発表 Many Applications Personal area networking cell phone, laptop, ear phone, wrist watch Military environments soldiers, tanks, planes Civilian environments taxi cab network meeting rooms Robot network Emergency operations search-and-rescue policing and fire fighting ITS & Sensor Networks

An Application Scenario DoCoMo成果発表 An Application Scenario Cellular and BS BS Cannot connect to BS directly. Using multi-hop Connection to BS A B

Many Protocols Proposed … DoCoMo成果発表 Many Protocols Proposed … ＤＳＲ　　　----- On-demand Source Routing ＡＯＤＶ ----- On-demand Table Driven ＬＡＲ ----- GPS-based Routing ＺＲＰ ----- Proactive Zone Routing, Hybrid →　But, these protocols mainly focus on connectivity and route discovery. Previous protocols realize efficient connectivity?

Problems of Conventional protocols Problem Definition DoCoMo成果発表 Problems of Conventional protocols Not identify the nearness of two nodes. For example, Never change the route unless the links fails, So ….. 1 2 3 シナリオ

Effect of Path Shortening DoCoMo成果発表 Effect of Path Shortening DSR (http://www.monarch.cs.rice.edu/) on FreeBSD, 5 Laptops with 802.11b NICs

DoCoMo成果発表 OR2 Solution Estimates the change of network topology (the nearness of two nodes) based on the local link state of SNR Re-routes the path adaptive to node mobility when the links are still active. 　Optimized Re-Routing（OR2） 1 2 3

Proximity : to identify the nearness OR2 Solution DoCoMo成果発表 Proximity : to identify the nearness The area around Node A where the received SNR value is more than a threshold. suppose that Node A and B are the same location if Node B is in the proximity of A. A B Proximity of Node A Cell We assume that all nodes in a network. Have the same NIC.

One-hop path shortening Proximity of Node C A B C C∈P(B) flow Proximity of Node A movement Proximity of Node B IF S(bc) > Smax THEN C∈P(B) C sends REQ to A A sends DATA to C S(bc) is the received SNR value of C. Smax is the threshold of proximity. P(B) is the proximity of Node B. S(bc) = S(cb) Symbol Definition

DoCoMo成果発表 Exclusive Control the cases that neighbor nodes initiate shortening the same path….. C flow time OR2_REQ OR2_REP OR2_RREQ Shorten route SSNR > Smax SSNR > Smin Smax > Smin B A B C D E F A

DoCoMo成果発表 OR2 features Local Decision using local link quality obtainable from own NIC. No periodic control packets. Network bandwidth, interference, power consumption By the Iteration of one hop shortening, we can shorten any hop route as possible. Applicable to previous routing protocols. Simple.

Evaluation by simulation Simulation Parameters 1500 m x 300 m, flat field, 50 mobile nodes. Speed uniformly distributed between 0 – 20 m/sec. Constant Bit Ratio UDP traffic (512 packet). Five runs with different mobility scenarios Variable The number of traffic sources Node Mobility Model (& Node Pause Time) Evaluation Metric Average Data Packet Delay Packet Delivery Ratio (PDR) Normalized routing overhead

Classified Mobility Models Random Way-Point Mobility Our Random Oriented Mobility Makes some node congestion points. This model is favorable for OR2. Our Random Escape Mobility Makes some network partition areas intentionally. Heavy loads to OR2. dst dst Select a random destination in the specified field space and moves to the destination at a speed distributed uniformly between 0 and some maximum speed. On reaching the destination, the node pauses again for pause time seconds, selects another destination.

Random Oriented Mobility Model Core Nodes Oriented Nodes 1 2 3 4 5 6 Random Escape Mobility Model Core Nodes Escape Nodes 1 2 3 4 5 6

Evaluation: 10 sources Avg. Delay Packet Delivery Ratio Routing Overhead Packet Delivery Ratio

Evaluation: 30 sources Avg. Delay Packet Delivery Ratio Routing Overhead Packet Delivery Ratio

Evaluation: in Oriented Mobility Avg. Delay Routing Overhead Packet Delivery Ratio

Simulation Results Summary OR2 improves the end-to-end delay as expected and reduces the routing control packet overhead effectively. In the packet delivery ration (PDR) of light traffic load scenario , OR2 loses about 5 % packets. In heavy traffic loads, OR2 has the highest performance of PDR. AODV with OR2 does not show the improved performance as salient as DSR with OR2. In our Random Oriented Mobility, we can see that the improved delay reduction is significant.

Implementation in our testbed DoCoMo成果発表 Implementation in our testbed As an extension to DSR on FreeBSD-4.4R SNR (from NIC driver) monitoring module OR2 routing table to maintain the upstream two-hop-away node’s information OR2 control packet for path shortening Using MELCO 802.11b NICs 　

Latency of Path Shortening Evaluation DoCoMo成果発表 Latency of Path Shortening Shortening time is the order of 10 ms. It is suitable for slow mobility (pedestrians and slow vehicle) Ｂ Ｃ Ａ Ｃ Ｂ Ａ

Future Works Simulation analysis. DoCoMo成果発表 Future Works Simulation analysis. Development of Signal power and supplemental location information based Wireless Routing Protocol in our testbed (iPAQs running Linux). Design of Transport protocol for Ad Hoc Networks. Simulation evaluation in popular 802.11b & 802.11a wireless LAN environments (in this work, we used 802.11[2Mbps] wireless LAN Network).

Today’s Summary We proposed Proximity-based Re-Routing Algorithm for Mobile Ad Hoc Networks. OR2 dynamically shortens active paths based on the proximity. Previously proposed routing protocols (e.g., DSR & AODV) were effectively enhanced by OR2. OR2 remarkably reduced the routing packet overhead and data packet latency.

Publications DoCoMo成果発表 M. Saito, H. Aida, Y. Tobe, Y. Tamura, and H. Tokuda　　　"A Dynamic Path Shortening Scheme in Ad Hoc Networks",情報処理学会 マルチメディア通信と分散処理ワークショップ (DPS)、2001年１０月、 Winner of the Best Presentation Award and Winner of the Young Researcher’s Award M. Saito, H. Aida, Y. Tobe, Y. Tamura, and H. Tokuda　"OR2: A Path Tuning Algorithm for Routing in Ad Hoc Network”, IEEE LCN on Wireless Local Networks (WLN), Tampa, FL, Nov. 2001.

DoCoMo成果発表 FIN Masato Saito, Tokuda Lab., Keio Univ.

Multi Hop Shortening

Evaluation: 10 sources Avg. Delay Packet Delivery Ratio Routing Overhead Packet Delivery Ratio

Evaluation: in Escape Mobility Avg. Delay Routing Overhead Packet Delivery Ratio