Direct Wireless Communication Research Articles

Separate linear receiver interfaces for MIMO multiple-access channels

We address the design of a receiver for the uplink of a direct sequence code division multiple access wireless communication system, endowed with multiple transmit and receive antennas and affected by multiple-access interference (MAI) for the presence of multiple transmitting users. The receiver is assumed to keep separate the tasks of mitigating the spatial and MAI in order to be implementable in two options: a baseline option accommodating the MAI mitigation interface only and an enhanced option accommodating the spatial interference mitigation interface as well. The MAI mitigating interface is based on standard linear multiuser detectors. The spatial interference mitigating interface is derived according to a linear minimum mean-square error criterion, which assumes the MAI mitigating interface to be given.

Wireless Inter-Vehicle Communication for Hazard Warning

Increasing automotive safety may be achieved by notifying drivers about incidents ahead. To enable drivers for proper reaction a warning system has been developed. Safety-related information is transmitted from one vehicle to surrounding vehicles by direct wireless data communication. The system evaluates some signals provided by the vehicle to detect hazardous conditions. Different strategies have been developed to decrease driver's interaction and to provide only relevant information to a specific driver. Simulations show a significant safety improvement due to the system if at least 10 to 15 percent of all vehicles are equipped with the systems.

The Progress of Directional Wireless Communication

FROM the earliest days of practical wireless com munication, it was realised that one of the most important services which this art would render to humanity was its contribution towards the safety of life at sea. The possibility of a ship being able to keep in communication with the remainder of the world during the longest voyages, and, in time of distress, to broadcast an appeal for assistance, has removed much of the terror of shipwreck and fire at sea. A later development, which bids fair to rank second in import ance to the above, is the direct application of wireless to aerial and marine navigation. There are, broadly, two methods by which a wireless signal may be used to determine the direction of any given fixed point. In the first, the direction of arrival of the signals from any transmitting station is determined by means of a direction-finder. The second method involves the transmission of a rotating beam of large or small angle and its reception on any suitable receiver.