Terminal Apparatus Carrier Sensing Waiting Time Management
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Solution Overview
Problem
Existing communication systems face challenges in ensuring transmission opportunities for a variety of radio apparatuses, including those carried by pedestrians, in road-to-vehicle and vehicle-to-vehicle communication systems, leading to potential interference and reduced effectiveness in preventing collisions.
Innovation Solution
A terminal apparatus is designed with a receiver to identify specific periods within a frame, a setting unit to set waiting times for carrier sensing, and a transmitter to send packets based on carrier sensing results, with adjustable waiting times to minimize interference between different types of terminal apparatuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a common waiting time range is set for all terminal apparatuses, then the system is simple to manage, but transmission opportunities are not ensured for all types of apparatuses
Solution Approach 1:
The patent applies local quality by setting different waiting time ranges for different types of terminal apparatuses. Specifically, portable terminal apparatuses are assigned a first waiting time range, while in-vehicle terminal apparatuses are assigned a second waiting time range. This differentiation ensures that each type of apparatus has appropriate transmission opportunities tailored to its characteristics, resolving the contradiction between fairness and simplicity.
2Productivity
If terminal apparatuses transmit simultaneously without coordination, then transmission efficiency is high, but collision probability increases
Solution Approach 1:
The patent implements periodic action through structured carrier sensing procedures and time-period-based transmission coordination. Terminal apparatuses perform carrier sensing during specific time periods and transmit only when the channel is clear, following a periodic pattern of sense-transmit-sense. This coordinated periodic behavior maintains high transmission efficiency while reducing collisions through systematic channel access control.
3Measurement precision
If carrier sensing time is extended, then collision detection accuracy improves, but transmission delay increases
Solution Approach 1:
The patent applies parameter changes by adjusting the waiting time parameter differently for different terminal apparatus types. Portable terminals use a first waiting time range that balances sensing accuracy and delay, while in-vehicle terminals use a second waiting time range optimized for their specific requirements. This parameter differentiation allows each apparatus type to achieve appropriate sensing accuracy without excessive delay.
Data Source
AI summary
An RF unit and a modem unit receive a packet signal, containing information regarding a frame construction, which is transmitted from a base station apparatus in a first period of a frame at least including first periods and second periods. An extraction unit identifies the second period in the frame, based on the received packet signal. A setting unit sets a waiting time period in the identified second period. A carrier sensing unit carries out carrier sensing over the waiting time period set by the setting unit. The modem unit and the RF unit broadcast the packet signal based on a result of the carrier sensing.