Selecting a set of antennas for use in a wireless communication system
Mechanisms for selecting a set of antennas for use in a wireless communication system are disclosed. The selected set of antennas is for use in communicating data in a wireless local area network (WLAN) comprising an access point and a plurality of mobile stations. The access point includes a baseband chip capable of adapting various radio frequency (RF) units. Each RF unit in turns includes a plurality of RF sub units, each of which connects to a plurality of antennas. The access point thus includes a number of antennas that, together with the RF units and the baseband chip, form a smart antenna. To identify the selected set of antennas to communicate with a particular mobile station, the access point initially uses a first set of antennas each in a RF sub unit. From this first set of antennas, the access point identifies a first set of winner antennas and a first set of non-winner antennas. From the first set of winner antennas, the access point identifies a first set of winner RF sub units each connecting to a winner antenna in the first set of winner antennas. From each winner RF sub unit, the access point identifies a final winner. The access point then uses the final winner antenna in the selected set of antennas. The access point also uses the first set of non-winner antennas in the selected set of antennas.
1. A method for selecting a set of antennas for use in a wireless communication system, comprising the steps of:
providing a plurality of radio-frequency sub units each connecting to a plurality of antennas;
using an antenna in each radio-frequency sub unit of the plurality of radio-frequency sub units to form a preliminary set of antennas;
in the preliminary set of antennas, identifying a set of preliminary winner antennas and a set of non-winner antennas; each preliminary winner antenna being distinct from each non-winner antenna;
from the set of preliminary winner antennas, identifying a set of winner radio-frequency sub units each including a preliminary winner antenna;
from each winner radio-frequency sub unit, identifying a final antenna in the plurality of antennas connected to the winner radio-frequency sub unit; and
using the final winner antenna from each winner radio-frequency sub unit to form the selected set of antennas.
2. The method of claim 1 further comprising the step of including at least one antenna in the set of non-winner antennas in the selected set of antennas.
3. The method of claim 1 wherein the plurality of radio-frequency sub units is connected to one another in one or a combination of series and parallel manner.
4. The method of claim 1 wherein the step of identifying the set of preliminary winner antennas comprising the step of selecting a preliminary winner antenna that provides data acceptable for use in the wireless communication system.
5. The method of claim 1 wherein the step of identifying the set of preliminary winner antenna comprising the step of identifying a mobile station communicating with an access point through the set of preliminary antennas, and selecting a preliminary winner antenna closer to the mobile station than a non-winner antenna.
6. The method of claim 1 wherein the step of identifying the set of preliminary winner antennas comprising the step of selecting a preliminary winner antenna corresponding to an adaptive weight having an amplitude higher than a threshold.
7. The method of claim 1 wherein the step of identifying the set of winner radio-frequency sub units comprising the step of identifying a winner radio-frequency sub unit that includes a preliminary winner antenna corresponding to an adaptive weight having an amplitude higher than a threshold.
8. The method of claim 1 wherein the step of identifying the final winner antenna in each winner radio-frequency sub unit comprising the steps of:
identifying a mobile station communicating with an access point through the set of preliminary antennas, and
identifying, as the final winner antenna, an antenna closest to the mobile station as compared to other antennas connected to the winner radio-frequency sub unit.
9. The method of claim 1 wherein the step of identifying the final winner antenna in each winner radio-frequency sub unit comprising the step of identifying an antenna that corresponds to an adaptive weight having the highest amplitude as compared to other weights that correspond to other antennas connected to the same winner radio-frequency sub unit.
10. The method of claim 1 wherein the step of identifying the final winner antenna in each winner radio-frequency sub unit comprising the step of identifying an antenna corresponding to an adaptive weight having the least adaptive error as compared to other adaptive weights that correspond to other antennas connected to the same winner radio-frequency sub unit.
11. The method of claim 1 wherein the step of identifying the final winner antenna in each radio-frequency sub unit comprising the steps of:
identifying a right winner antenna in a right set of antennas to the right of the preliminary winner antenna in each radio-frequency sub unit and a left winner antenna in a left set of antennas to the left of the preliminary winner antenna in each radio-frequency sub unit, and
identifying the final winner antenna among the right winner antenna, the left winner antenna, and the preliminary winner antenna in each radio-frequency sub unit.
12. An access point for use in a wireless communication system, comprising:
a plurality of radio-frequency sub units each connecting to a plurality of antennas;
a baseband unit connecting to the plurality of radio-frequency sub units, and
a set of final antennas in the plurality of antennas of the plurality of the radio-frequency sub units, for communicating with a mobile station;
wherein the baseband unit including a smart-antenna engine for
identifying an antenna in each radio-frequency sub unit of the plurality of radio-frequency sub units to form a preliminary set of antennas;
identifying a set of adaptive weights each corresponding to an antenna in the preliminary set of antennas;
identifying a set of winner weights in the set of adaptive weights; each winner weight corresponding to a winner antenna;
identifying a set of winner radio-frequency sub units each connecting to a winner antenna;
from each winner radio-frequency sub unit, identifying an antenna in the plurality of antennas connected to the each winner radio-frequency sub unit as a final winner antenna; and
including the final winner antenna in each winner radio-frequency sub unit in the set of final antennas for communicating with the particular mobile station.
13. The access point of claim 12 wherein a winner weight in the set of adaptive weights having an amplitude higher than a threshold.
14. The access point of claim 12 wherein the final winner antenna in a winner radio-frequency sub unit corresponds to an adaptive weight selected from one or a combination of a weight having the highest amplitude as compared to other weights corresponding to other antennas in the same winner radio-frequency sub unit and a weight having the least adaptive error as compared to other weights corresponding to other antennas in the same winner radio-frequency sub unit.