DORA: Dynamic Optimal Random Access

Vehicle-to-Roadside Communications

ABSTRACT

In this project, we use random access in a drive thru scenario, where roadside access points (APs) are

installed on a highway to provide permanent Internet access for vehicles.We consider vehicle-to-

roadside (V2R) communications for a vehicle that aims to upload a file when it is within the APs’

coverage ranges, where both the channel contention level and transmission data rate vary over time.

The vehicle will pay a fixed amount reach time it tries to access the APs, and will incur a penalty if it

cannot finish the file uploading when leaving the APs. First, we consider the problem of finding the

optimal transmission policy with a single AP and random vehicular traffic arrivals. We formulate it as a

finite-horizon sequential decision problem, solve it using dynamic programming (DP), and design a

general joint dynamic optimal random access (JDORA) algorithm.We derive the conditions under which

the optimal transmission policy has a threshold structure, and propose a monotone DORA algorithm

with a lower computational complexity for this special case. Next, we consider the problem of finding

the optimal transmission policy with multiple APs and deterministic vehicular traffic arrivals thanks to

perfect traffic estimation. We again obtain the optimal transmission policy using DP and propose a joint

DORA algorithm..

Existing System

A number of previous results have been reported on the resource allocation in V2R communications. In

considered the case where roadside APs only store the data uploaded by the vehicles. Scheduling

priority is determined by two factors: data size and deadline. A request with a smaller data size or an

earlier deadline will be served first. Hadaller et al. in proposed a scheduling protocol that grants channel

access to a vehicle with the maximum transmission rate. Analytical and simulation results showed

significant overall system throughput improvement over a benchmark scheme.

ARCHITECTURE OF EXISTING SYSTEM

Disadvantage of Exiting System

Less uploading ratio

High total cost

High threshold nodes occur

Proposed System

We proposed an optimal random access algorithm based on the analysis of finite-horizon dynamic

programming. our scheme achieves the minimal total cost, the highest probability of completing file

upload, and the highest upload ratio comparing with two other heuristic schemes.

Advantage:

High upload ratio

Less total cost

Less threshold node occur

Proposed System Architecture

Software Requirements

C,C++ compiler for Linux

TCL Compiler

NS 2.34

Linux OS

Hardware Requirements

Hard Disk : 20GB and Above

RAM : 512 MB and Above

Processor : Pentium IV and Above