Physical layer modeling and analysis for Vehicle-to-Vehicle networks.

摘要

Future vehicles are likely to rely on the Vehicle-to-Vehicle (V2V) Ad Hoc Network concept to increase safety and comfort on road. Wireless communication acts as a new "sensor" which allows the drivers to look further away in space and further ahead in time. The growth in potential applications imposes a pressing need for new physical layer studies to preserve reliable operation in dynamic on-road environments.;This thesis designed and implemented a fully mobile, location-aware sounding platform which has a large dynamic range, extensive flexibility in transmission frequency and modulation for narrowband and wideband measurements. An accurate synchronization and position location system was developed for recording channel performance with vehicle speed, separation and location. We used the field implementation of the system for systematic experimental studies of V2V channel under general onroad driving conditions across suburban, highway, and rural environments. Large data sets were obtained that cover a rich set of on-road driving scenarios and topologies across three environments.;The behavior of the V2V channel was investigated from multiple dimensions: (1) The large dynamic range of the system allows us to develop signal strength based models with different granularity. (2) Doppler spread and coherence time properties were analyzed together with mobility, separation driver behavior and environments. (3) We introduce the Speed-Separation (S-S) diagram as a new tool for understanding and estimating Doppler spread and coherence time in the V2V environment, which enables a convenient methodology to generate accurate small-scale fading using only a model of driving behavior, with or without actual measurements. (4) Broadband sounding using zero correlation zone sequences was conducted with an instantaneous bandwidth of about 40 MHz. Multi-path properties have been investigated both in the time delay domain and frequency domain. (5) We have presented a systematic study concerning the effects of a mobile V2V channel on scaled versions of the current IEEE 802.11a standards. Aiming at investigating how readily the scaled versions of the 802.11a waveform can be applied to vehicular networks, we have extracted, quantified and analyzed measured parameters for the V2V channel at 5.9 GHz in suburban, highway, and rural environments. The critical design parameters for the 802.11a PHY have been examined in detail along with the actual performance of scaled waveforms with bandwidths of 20 MHz (a), 10 MHz (p), and 5 MHz (p/2). (6) We have also developed geometrical modeling complimentary to measurement based models.