Method of improving transmission gain at a network element having a plurality of antennas
In one embodiment, the method includes reducing a beam width of transmission to increase an open-loop beamforming gain, reducing a channel bandwidth of the transmission to increase a channel bandwidth gain, and increasing a sequence length of the transmission to increase a sequence length gain. In this embodiment, a gain improvement is based on the product of the open loop beamforming gain, the channel bandwidth gain and the sequence length gain.
1. A method of improving transmission gain at a network element having a plurality of antennas, comprising:
reducing a beam width of transmission to increase an open-loop beamforming gain;
reducing a channel bandwidth of the transmission to increase a channel bandwidth gain; and
increasing a sequence length of the transmission to increase a sequence length gain; wherein
a gain improvement is based on the product of the open loop beamforming gain, the channel bandwidth gain and the sequence length gain.
2. The method of claim 1 , wherein the reducing a beam width reduces the beam width to a minimum beam width of the network element.
3. The method of claim 1 , wherein the reducing a beam width reduces the beam width below an angular spread associated with the network element.
4. The method of claim 1 , wherein the reducing a beam width reduces the beam width by a fixed amount.
5. The method of claim 1 , wherein the reducing a channel bandwidth reduces the channel bandwidth to one sub-carrier.
6. The method of claim 1 , wherein the reducing a channel bandwidth reduces the channel bandwidth by one sub-carrier.
7. The method of claim 1 , wherein the reducing a channel bandwidth reduces the channel bandwidth by a fixed amount.
8. The method of claim 1 , wherein the increasing increases the length of a synchronization sequence for cell search.
9. The method of claim 1 , wherein the increasing increases redundancy of repetition coding for paging.
10. The method of claim 1 , wherein the increasing and the reducing a channel bandwidth are performed such that the channel bandwidth gain times the sequence length gain is less than
1
τ
N
,
where N is the maximum number of messages sent per second on a broadcast channel and τ is the duration of each message.
11. The method of claim 1 , further comprising:
beamforming using the reduced beam width.
12. The method of claim 1 , further comprising:
rotating beams; and
beamforming using the reduced beam width.
13. The method of claim 1 , wherein the rotating rotates the beams by one-half of the reduced beam width.
14. The method of claim 1 , further comprising:
determining a desired gain improvement; and wherein
the reducing a beam width, the reducing a channel bandwidth and the increasing steps are performed to obtain the desired gain improvement.
15. The method of claim 14 , wherein
the reducing a beam width reduces the beam width by a first fixed amount;
the reducing a channel bandwidth reduces the channel bandwidth by a second fixed amount;
the increasing increases the sequence length by a third fixed amount; and wherein
the reducing a beam width, the reducing a channel bandwidth and the increasing steps are repeated until the desired gain improvement is obtained.