# US 7,181,176 B2 · Closed loop transmit diversity of point to multipoint physical channels

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- Number: US 7,181,176 B2
- Document ID: US7181176B2
- Status: Granted
- Kind: B2
- Application number: 10/637,023
- Filed: 2003-08-07
- Published: 2004-05-20
- Granted: 2007-02-20
- Earliest claimed: 2002-08-07
- Assignees: InterDigital Technologies Corporation
- Inventors: Stephen E. Terry; Ariela Zeira
- Web page: https://patentgrep.com/patent/US7181176B2

## CPC

- H04B 7/0634: {Antenna weights or vector/matrix coefficients}
- H04B 7/0689: {using different transmission schemes, at least one of them being a diversity transmission scheme}
- H04B: TRANSMISSION

## Abstract

Data is to be transmitted from one transmitting point to multiple reception points in a wireless communication system. A transmitting antenna array has multiple antenna elements at the one transmitting point. Channel information is measured for each antenna element at each reception point. Antenna adjustments are determined using the measured channel information. The measured channel information from all of the users is correlated to determine weighting factors for each antenna element. The weighting factors to a point to multiple point transmission are applied prior to being radiated by each antenna element.

## Claims

### Claim 1

A wireless transmit/receive unit (WTRU) comprising:
a point to multi-point channel estimation device for determining a channel response for each transmitted version of a point to multi-point transmission, each transmitted version originating from a different transmitting antenna element and the point to multi-point channel being sent to multiple WTRUs simultaneously, the point to multi-point transmission being sent using transmit diversity using weight values from multiple WTRUs; and
a transmit diversity phase/amplitude signaling device for determining weight values representing phase/amplitude values for each transmitting antenna and signaling the determined weights and determining whether a link quality when transmit diversity is applied is equal to or better than when transmit diversity is not applied and whereby transmit diversity is not applied when any of the multiple WTRUs does not have an equal to or better than link quality when transmit diversity is applied.

### Claim 2

A wireless transmit/receive unit (WTRU) comprising:
means for determining a channel response for each transmitted version of a point to multi-point transmission, each transmitted version originating from a different transmitting antenna element and the point to multi-point channel being sent to multiple WTRUs simultaneously, the point to multi-point transmission being sent using transmit diversity using weight values from multiple WTRUs; and
means for determining weight values representing phase/amplitude values for each transmitting antenna and signaling the determined weights and determining whether a link quality when transmit diversity is applied is equal to or better than when transmit diversity is not applied and whereby transmit diversity is not applied when any of the multiple WTRUs does not have an equal to or better than link quality when transmit diversity is applied.