.pi./4-DQPSK delay spread detection and compensation apparatus and method
US5550868A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 3, 1994 |
| Grant date | Aug 27, 1996 |
| Priority date | — |
| Expiry date | Mar 3, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/22
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A .pi./4 delay spread detection and compensation arrangement effectively detects distortion due to multipath delay spread in a digital channel and compensates for this distortion with minimum circuit complexity. An improvement in the bit error rate performance for a differential detector in the receiver is achieved through use of a detected direct current (DC) component, which is proportional to the amount of multipath delay spread on the digital channel. This DC component is used in the differential detector for compensating for this delay spread. In addition, the differential detector also provides a channel quality measure of the level of delay spread on the digital channel for use by the receiver in selecting either the differential detector or an equalizer for decoding of the data on the digital channel. When the level of delay spread is low, a processor used by the equalizer is freed for other computational tasks or, when the bit error rate permits, is not used at all thereby realizing a reduction in power consumption in the receiver.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.