In a wireless home network, shadowing is frequently caused by human bodies or furniture. Therefore, relay transmission function is considered for the hub station in Wireless Homelink when the direct communication of terminals is obstructed. However, in relaying high rate isochronous data such as video streams, the bandwidth resource of Wireless Homelink may be crammed with those data. In this paper, we propose an efficient relay scheme--"Pipeline Repeater" for Wireless Homelink. The proposed scheme spatially multiplexes the relay transfer of the isochronous data using antenna directivity. The Pipeline Repeater can relay the isochronous packets as an efficient use of the limited frequency band, and it can be achieved to repeat the high rate data with delay of only one frame. To verify the proposed scheme, we conduct measurements in some actual home environments, and perform the numerical analyses and computer simulations based on the measurements. Our results confirm the efficiency of the Pipeline Repeater scheme.

We investigated the use of the Wireless 1394 standard in an intra-vehicle environment. Wireless 1394 services are expected to be used both in homes and in vehicles, however the installation of twisted wire pairs in a car is difficult. In a vehicular environment, there is a problem of interference from nearby vehicles using the same frequency. In this paper, we examined the above problem of interference for vehicles using Wireless 1394 equipments, and measured the propagation characteristics between a transmitter in one vehicle and a receiver in another vehicle. We developed a mitigation method, based on the use of directional antennas as a solution to the problem of interference.