1. Field of the Invention
The present invention relates to communications; more specifically, wireless communications.
2. Description of the Related Art
Prior communication systems have been designed around one type of transmit configuration. In older systems, a single antenna is used for transmitting. In newer systems, one of several other types of transmit configurations have been used but they did not provide flexibility to address channel conditions such as the degree of mobility associated with a mobile station.
The present invention provides a communication system with a transmit configuration that may be reconfigured based on mobile station associated conditions such as the capability of the mobile receiver, carrier to interference or signal to noise ratios, and the degree of mobility associated with the mobile station. As a result, the transmit configuration is optimized for the conditions associated with a particular mobile receiver. In one embodiment, the transmit configuration may be selected to operate in configurations such as a single transmit antenna configuration, a space time spreading configuration, a selective transmit diversity configuration, and a multi-output and multi-input configuration.
When a mobile station initially makes contact with a base station requesting a communication channel, it transmits information such as its electronic serial number (ESN), and mobile associated channel conditions such as carrier to interference ratio
signal to noise ratio
the mobile station's degree of mobility (whether the mobile is standing still, moving slowly or moving at a relatively high speed) and the transmit configurations supported by the mobile. Additionally, the base station transmits its capabilities to mobile stations on a channel such as a paging channel or synchronization channel where is indicates the types of transmit configurations that are available. In one embodiment, based on the information provided by the mobile station and the capabilities of the base station, the base station provides one of four different transmit configurations for communications with the mobile station. The selected transmit configuration is communicated to the mobile station using a control channel such as a paging channel or synchronization channel.
In one embodiment, the four transmit configurations are a single transmit antenna configuration, a selective transmit diversity configuration, a space time spreading configuration and a multi-input/multi-output configuration. The use of these four configurations is provided for instructional purposes. Different numbers and different types of configurations may be used.
Other types of known configurations may be used or a subset of the above described configurations may be used based on the capabilities of the base station and mobile station associated channel conditions such as the capabilities of the mobile station, carrier to interference ratio, the signal to noise ratio and the mobile station's mobility.
Number | Name | Date | Kind |
---|---|---|---|
5140695 | Yasuda et al. | Aug 1992 | A |
5628052 | DeSantis et al. | May 1997 | A |
5666649 | Dent | Sep 1997 | A |
5722051 | Agrawal et al. | Feb 1998 | A |
5794145 | Milam | Aug 1998 | A |
5859874 | Wiedeman et al. | Jan 1999 | A |
6006117 | Hageltorn et al. | Dec 1999 | A |
6201967 | Goerke | Mar 2001 | B1 |
6208297 | Fattouche et al. | Mar 2001 | B1 |
6392988 | Allpress et al. | May 2002 | B1 |
6456604 | Lee et al. | Sep 2002 | B1 |
6542736 | Parkvall et al. | Apr 2003 | B1 |
6594226 | Benning et al. | Jul 2003 | B1 |
6600934 | Yun et al. | Jul 2003 | B1 |
Number | Date | Country |
---|---|---|
0 966 125 | Dec 1999 | EP |
WO 99 14871 | Mar 1999 | WO |
WO 99 39454 | Aug 1999 | WO |