A WLAN-type scenario where a base-station (access point) equipped with multiple antennas is transmitting and a mobile with only a single antenna is receiving, is considered. Three approaches are investigated: grid-of-beams (GOB), maximal-ratio (MR) and equal-gain (EG), each with one of the following constraints 1) total transmit power over all antenna elements, 2) maximum power on any antenna element 3) equivalent isotropic radiated power (EIRP). The median diversity gain for the MR approach is estimated to be 14.8 dB, 10.6 dB, and 11.4 dB using constraint 1-3, respectively at 5.2 GHz in a modern university building at 5-50 meter range. For GOB corresponding numbers are 9.4 dB, 9.4 dB, 2.3 dB and for EG 13.9 dB, 13.9 dB, 10.3 dB, respectively. These results are virtually independent of delay between channel estimation and use of the same estimate, when the delay is less than 130 ms. This result is obtained although there were people moving in the environment. The diversity gain under the EIRP constraint is encouraging and shows that coverage improvements are possible even under EIRP limitations.
|Translated title of the contribution||Downlink beamforming with delayed channel estimates under total power, element power and equivalent isotropic radiated power (EIRP) constraints|
|Title of host publication||IEEE VTC|
|Publisher||Institute of Electrical and Electronics Engineers (IEEE)|
|Pages||516 - 520|
|Publication status||Published - Sep 2001|
|Event||54th Vehicular Technology Conference 2001 (VTC 2001-Fall) - Atlantic City, United States|
Duration: 1 Oct 2001 → …
|Conference||54th Vehicular Technology Conference 2001 (VTC 2001-Fall)|
|Period||1/10/01 → …|
Bibliographical noteOther: Proceedings
Rose publication type: Conference contribution
Sponsorship: This report is a part of the work done within the EU IST-SATURN project
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- wireless LAN