C2C communication with MIMO...

Berkeley tested the MIMO system (from LitePoint) in vehicular environments.

See the original article:
"
Berkeley Researchers Exploring DSRC Channel with LitePoint MIMO Test System

They're using IQnxn^plus to better understand channel characteristics and to test innovations

BERKELEY, CA — October 22, 2008 — Using one of the first LitePoint IQnxn^plus units to be shipped, Connectivity Lab researchers at University of California, Berkeley, are delving deeper into the channel characteristics of vehicles in motion communicating via dedicated short-range communications (DSRC) based on IEEE 802.11p. Using a 4x4 MIMO configuration, the team is now able to "see" multiple incoming waves, their directions and angles, and their interactions.

"Before, we were looking at the composite effects of the multipath signals but had no way to examine the various wave contributions. IQnxn^plus, using separate antennas, VSAs, and VSGs lets us better understand what’s going on in the physical channel," explained Ian Tan, a Berkeley graduate student and team member.

In addition, Tan said, the IQnxn^plus is being developed into a software-defined-radio (SDR) test bed. "It will provide a hardware platform for rapid prototyping of any improved communications schemes or beam-forming algorithms our group proposes. Naturally, seeing performance improvements with real hardware and software is much better than just simulations."

About DSRC

DSRC refers to one-way or two-way, short- to medium-range wireless communications methods intended specifically for automotive applications. Some applications envisioned using DSRC include: emergency warning system for vehicles, cooperative adaptive cruise control, cooperative forward collision warning, and intersection collision avoidance.

IEEE 802.11p is associated with DSRC. It is a draft amendment to the IEEE 802.11 standard that adds wireless access targeted for the vehicular environment, and defines enhancements to 802.11 aimed at supporting Intelligent Transportation Systems (ITS) applications. This includes data exchange between high-speed vehicles and between the vehicles and the roadside infrastructure in the licensed ITS band of 5.9 GHz (5.85-5.925 GHz).

Prior DSRC Work by Berkeley

The Connectivity Lab, working under the guidance of Professor Ahmad Bahai, had completed an earlier phase of DSRC exploration that looked at the effect of channel impairments on communications efficiency. "A lot of 802.11p specifications are based on 802.11a, which, in turn, targets primarily indoor wireless applications with stationary or slowly-moving radios," Tan explained. "At highway speeds, with multipath signals under both line-of-sight and non-line-of-sight conditions, it is possible that 802.11p specifications could fall short on avoiding inter-carrier interference. Our work, using IQview VSAs and omni-directional antennas produced data from over 200 locations and required 50 GBs of storage. We found that, for the most part, 802.11p was suitable to the DSRC automotive environment for short packets. However, with longer packets, channel variance over the longer transmission times will exacerbate inter-carrier interference. As a result, we believe there are opportunities for enhanced performance with improved processing."

Current DSRC Work

The next phase of the Connectivity Lab’s research is to explore innovations, such as multi-antenna beamforming, that increase the communications robustness of 802.11p in environments with increased RF congestion, harsher multipath, and greater inter-vehicle distances "Here is where the MIMO tools of IQnxn^plus, and its use as an SDR test bed, will help us propose ways to improve DSRC communications," Tan concluded.

About LitePoint Corporation

LitePoint Corporation, based in Sunnyvale California, designs, develops, markets, and supports advanced wireless test solutions for: developers and marketers of branded wireless products; consumer electronics and contract manufacturers; and wireless IC designers. Through its in-house expertise in the design of wireless systems and ICs, LitePoint has developed innovative test solutions to assure products conform to specifications, interoperate with other compliant products, and perform as described. LitePoint's test products address both development and high-volume production, providing its customers with superior return on investment, accelerated time-to-market, improved manufacturing yields, improved product quality, and increased profitability. For more information, visit LitePoint at www.litepoint.com. "

As well, see here:
Berkeley Researchers Exploring DSRC Channel with LitePoint MIMO Test System
(Business News & Technology News, 23 Oct 2008)