Abstract: A method and system for protecting a wireless network by establishing virtual walls to confine wireless connection to devices located within a three-dimensional region. A network of wireless monitoring nodes is established at physical locations. The monitoring nodes are arranged in a frame of reference and determine locations of one another and of mobile nodes by conducting measurements of either roundtrip travel time of signals sent and received or of differences in the times of receiving a signal at different known locations. Initially mobile nodes are placed, sequentially, in a triangle at a boundary to be established as a virtual wall for confining communication within the wireless network. The mobile node locations are then stored. The position of a device requesting admission to the wireless network is similarly determined and, if within the established virtual walls, the device may be admitted to the network. Admission is otherwise denied.

Abstract: A shared wire serial interface between two devices that share a system clock and a single bi-directional serial data line. The clock drives both the system and the interface and is provided over a single clock wire. One device operates as a master, the other as a slave. Since master and slave share the same clock, clock drift error will be zero. Although the start of a data transfer is asynchronous with regard to the system clock, the data transfer itself, is synchronous. In one embodiment, the bit transfer rate is ⅛th the system clock speed in one example and is generated by a state machine, however, any divide may be used. The state machine also signals the output enablers which interleave the data bits on the serial data line. The flow of data on a single data line of the interface is bi-directional in that data from the master is bit interleaved with data from the slave.