# A TDMA-like Access Scheme with Splitting Request and Transmission for Vehicular Networks

## TL;DR

This paper introduces RTS-TDMA, a novel access scheme for dense vehicular networks that improves safety message transmission reliability and throughput by splitting request and transmission phases and using interference cancellation.

## Contribution

The paper proposes RTS-TDMA, a new request-transmission split TDMA scheme with collision resolution and reduced request time, enhancing safety message delivery in dense vehicular networks.

## Key findings

- RTS-TDMA achieves higher throughput than coded slotted ALOHA.
- The scheme reduces request time percentage.
- Theoretical and numerical analysis confirm improved performance.

## Abstract

In this paper, we consider safety message transmission in a dense vehicular network. With increasing vehicular network density, the collision rate increases when multiple vehicles transmit safety messages simultaneously. To address this issue, we propose a request-transmission split time division multiple access (TDMA) scheme, referred to as RTS-TDMA. In our scheme, we divide a frame into three phases, i.e., a contention access phase, a broadcast feedback phase, and a contention-free transmission phase. Each vehicle selects a repetition rate according to a given probability distribution and repeats the transmission of its request packet to improve the reliability of the request. In addition, a roadside unit acts as the coordinator and uses a successive interference cancellation technique to resolve request collisions. RTS-TDMA also reduces the request time percentage by containing only the vehicle identity in each request packet. Both theoretical analysis and numerical results verify that the RTS-TDMA scheme can provide higher throughput than the coded slotted ALOHA scheme.