Downlink beamforming with delayed channel estimates under total power, element power and equivalent isotropic radiated power (EIRP) constraints
2001 (English)In: IEEE 54TH VEHICULAR TECHNOLOGY CONFERENCE, VTC FALL 2001, 2001, 516-520 p.Conference paper (Refereed)
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 was estimated to be 14.8dB, 10.6dB, and 11.4dB using constraint 1-3, respectively at 5.2GHz in a modern University building at 5-50 meter range. For GOB corresponding numbers are 9.4dB,9.4dB,2.3dB and for EG 13.9dB,13.9dB,10.3dB, respectively. These results were virtually independent of delay between channel estimation and use of the same estimate, when the delay is less than 130ms. This result was 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.
Place, publisher, year, edition, pages
2001. 516-520 p.
, IEEE VTS Vehicular Technology Conference Proceedings, ISSN 1090-3038
IdentifiersURN: urn:nbn:se:kth:diva-35011DOI: 10.1109/VTC.2001.956654ISI: 000173938400108OAI: oai:DiVA.org:kth-35011DiVA: diva2:424357
54th IEEE Vehicular Technology Conference (VTC 2001) ATLANTIC CITY, NJ, OCT 07-11, 2001
QC 201106172011-06-172011-06-172011-11-04Bibliographically approved