1. Wireless LAN Support For 3COM Palm Pilot Winter/Spring 2000 Technion – Israeli Institute of Technology Computer Networks and Digital Labs Yuval Frandzel & Alec Shnapir

2. Project Goals Definition of a wireless network for distribution of information to PDA devices. Simulation of the proposed network and performance analysis in several configurations. Comparison of the proposed network with the CSMA protocol.

3. Description With the emergence of a new mobile breed of computing platform – the handheld Personal Digital Assistant (PDA) – the possibility of distributing personalized information to users “ on the go ” in public venues has become a reality. This information distribution is envisioned as a user transparent, web like experience whereby a user surfs for information on his PDA. The PDA communicates with a local information server, or “ information kiosk ”, placed in the facility where the user is (e.g. malls, airports etc.).

4. Description (cont…) The most obvious form of mobile communication is a wireless, radio frequency network. This project discusses the primary issues affecting such a network, proposes a MAC protocol to address these issues and analyzes the results of several simulations of the proposed protocol in varying configurations. In addition, the project describes how to cover large areas with a cellular arrangement.

5. Existing Characteristics Users are mobile. Server messages are longer than client messages.

6. System Requirements Cheap. Low power usage. User transparent operation. Allow easy detection of network by new clients.

7. MAC Protocol Characteristics Server messages have priority. Predefined, bound number of clients can be processed at once in every cell. Access points always transmit at regular intervals. Overall cellular layout of access points in the network.

8. Description of MAC protocol 1 23 12 n T ms TdTd TpTp T rt,3 T rt,2 T rt,1 T mc 3 T fs,max T rt, n =T p - (n -1) * T d - (n - 2) * T mc +n * T ms + (n -1) * T fs,max T fs,max = n max* (T mc + T d )

9. Overview of Operation Client wants to send a request Request by clientACK by AP Answer by AP TpTms Trt TmcTtx AP CLIENT Ttx – time to successful transmission Tmc – client’s message transmission time Tms – AP’s message transmission time Tp – server’s response time Trt – roundtrip time

10. Simulation Goals Overall behavior of the new protocol. Comparison between the new protocol and vanilla CSMA. Comparison of different AP channel governing policies –No short –Binary –Linear

11. Simulation Results

12. Simulation Results (cont…)

13. Conclusions The proposed protocol out performs vanilla CSMA. The simulation found that out of the three AP channel governing policies, the binary policy was the best.