Cellular communication system with multiple code rates
US5729557A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 12, 1995 |
| Grant date | Mar 17, 1998 |
| Priority date | — |
| Expiry date | Oct 12, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L69/18
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for using multiple code rates for forward error correction in a cellular digital data radio communication system. Each base station broadcasts a quantity called the power product (PP), which is equal to the base station transmit power, P.sub.BT, multiplied by the power level received at the base station, P.sub.BR. For a mobile unit to determine its appropriate transmit power, P.sub.MT, requires measuring the power received, P.sub.MR, at the mobile unit and performing the following calculation: P.sub.MT ==PP/P.sub.MR. When channel path loss is large, it is possible that the power control calculation will return a value greater than the maximum transmit power capability of the mobile unit. In such a case, the mobile unit selects a lower code rate. Base station receiver sensitivity improves as the code rate decreases, so the result is similar to increasing the transmitter power. In the preferred embodiment, the invention uses 3 different code rates. In most cases, the code rate used is rate 2/3, but when a mobile unit determines that it needs more transmit power than it is capable of providing, the code rate is changed to 1/2, and in severe cases the code rate i…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.