Apparatus and method for alerting computer users in a wireless LAN of a service area transition
US5467341A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 14, 1994 |
| Grant date | Nov 14, 1995 |
| Priority date | — |
| Expiry date | Apr 14, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W84/12
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An apparatus and method is provided for detecting when a mobile computer linked to a computer server over a wireless link is about to move out of the range of the LAN and for alerting the computer user before the communication link with the computer server becomes severely deteriorated. According to the apparatus and method, a predetermined number of data packets are periodically transmitted from the mobile computer to the computer server, and the number of data packets successfully transmitted is determined based on acknowledgments received from the computer server, preferably using a cyclical redundancy check (CRC) code in the transmitted packets. Based on the number of data packets successfully transmitted, a transmission error rate is computed. The error rate is compared to a threshold value and, if the threshold is exceeded, an indication is provided to the user that the communication quality is deteriorating. Parameters for controlling the number of predetermined packets, the time interval for repeating the transmissions, the method of indication, and the thresholds may be changed by the user to adapt to different requirements and environments. In a preferred embodiment, tran…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.