Wireless communication method and apparatus for selecting and reselecting cells based on measurements performed using directional beams and an omni-directional beam pattern
A wireless communication method and apparatus for selecting and reselecting cells used by a wireless transmit/receive unit (WTRU) in a wireless multi-cell communication system. The WTRU includes a switched beam antenna configured to form a plurality of directional beams and an omni-directional beam pattern. The WTRU measures signals from a plurality of cells using the directional beams and the omni-directional beam pattern. The WTRU selects and registers with the cell having the strongest signal. In one embodiment, the WTRU selects a directional beam which has the strongest signal and uses it as an active beam to communicate with the selected cell. In another embodiment, the WTRU selects a cell/beam combination and registers with the selected cell using the selected beam. In yet another embodiment, the WTRU initiates a handoff to a neighboring cell that has a better signal measurement result than the selected cell.
1. In a wireless communication system including at least one wireless transmit/receive unit (WTRU) and a plurality of cells, the WTRU being configured to include a switched beam antenna for generating a plurality of directional beams and an omni-directional beam pattern, a cell selection method comprising:
(a) the WTRU performing measurements on signals received from the cells using the directional beams and the omni-directional beam pattern;
(b) the WTRU selecting a cell/beam combination having the strongest signal based on the results of the measurements performed in step (a); and
(c) the WTRU registering with the selected cell using the selected beam as an active beam used for communicating with the selected cell.
2. The method of claim 1 further comprising:
(d) if the selected beam is not an omni-directional beam pattern, comparing a measurement result which indicates the best directional beam/cell combination with the measurement result which indicates the best omni-directional beam pattern/cell combination.
3. The method of claim 2 wherein a directional beam is selected if the measurement result associated with the directional beam exceeds the measurement result associated with the omni-directional beam pattern by a predetermined threshold, and the omni-directional beam pattern is selected when the measurement result associated with the directional beam does not exceed the measurement result associated with the omni-directional beam pattern.
4. In a wireless communication system including at least one wireless transmit/receive unit (WTRU) and a plurality of cells, the WTRU being configured to include a switched beam antenna for generating a plurality of directional beams and an omni-directional beam pattern, a cell selection method comprising:
(a) the WTRU performing measurements on signals received from the cells using the omni-directional beam pattern;
(b) the WTRU selecting a subset of the cells based on the results of the measurements performed in step (a);
(c) the WTRU performing measurements on signals received from the subset of cells using each of the directional beams;
(d) the WTRU selecting a cell/beam combination having the strongest signal based on the results of the measurements performed in step (c); and
(e) the WTRU registering with the selected cell using the selected beam as an active beam used for communicating with the selected cell.
5. In a wireless communication system including a plurality of cells, a wireless transmit/receive unit (WTRU) comprising:
(a) a switched beam antenna for generating a plurality of directional beams and an omni-directional beam pattern;
(b) means for performing measurements on signals received from the cells using the directional beams and the omni-directional beam pattern;
(c) means for selecting a cell/beam combination having the strongest signal based on the results of the measurements performed using either the directional beams or the omni-directional beam pattern; and
(d) means for registering with the selected cell using the selected beam as an active beam used for communicating with the selected cell.
6. The WTRU of claim 5 further comprising:
(e) means for comparing a measurement result which indicates the best directional beam/cell combination with the measurement result which indicates the best omni-directional beam pattern/cell combination, if the selected beam is not an omni-directional beam pattern.
7. The WTRU of claim 6 wherein a directional beam is selected if the measurement result associated with the directional beam exceeds the measurement result associated with the omni-directional beam pattern by a predetermined threshold, and the omni-directional beam pattern is selected when the measurement result associated with the directional beam does not exceed the measurement result associated with the omni-directional beam pattern.
8. In a wireless communication system including a plurality of cells, a wireless transmit/receive unit (WTRU) comprising:
(a) a switched beam antenna for generating a plurality of directional beams and an omni-directional beam pattern;
(b) means for performing measurements on signals received from the cells using the omni-directional beam pattern;
(c) means for selecting a subset of the cells based on the results of the measurements using the omni-directional beam pattern;
(d) means for performing measurements on signals received from the subset of cells using each of the directional beams;
(e) means for selecting a cell/beam combination having the strongest signal based on the results of the measurements performed using each of the directional beams; and
(f) means for registering with the selected cell using the selected beam as an active beam used for communicating with the selected cell.
9. In a wireless communication system including a plurality of cells, an integrated circuit (IC) operating in conjunction with a switched beam antenna for generating a plurality of directional beams and an omni-directional beam pattern, the IC comprising:
(a) means for performing measurements on signals received from the cells using the directional beams and the omni-directional beam pattern;
(b) means for selecting a cell/beam combination having the strongest signal based on the results of the measurements performed using either the directional beams or the omni-directional beam pattern; and
(c) means for registering with the selected cell using the selected beam as an active beam used for communicating with the selected cell.
10. The IC of claim 9 further comprising:
(d) means for comparing a measurement result which indicates the best directional beam/cell combination with the measurement result which indicates the best omni-directional beam pattern/cell combination, if the selected beam is not an omni-directional beam pattern.
11. The IC of claim 10 wherein a directional beam is selected if the measurement result associated with the directional beam exceeds the measurement result associated with the omni-directional beam pattern by a predetermined threshold, and the omni-directional beam pattern is selected when the measurement result associated with the directional beam does not exceed the measurement result associated with the omni-directional beam pattern.
12. In a wireless communication system including a plurality of cells, an integrated circuit (IC) operating in conjunction with a switched beam antenna for generating a plurality of directional beams and an omni-directional beam pattern, the IC comprising:
(a) means for performing measurements on signals received from the cells using the omni-directional beam pattern;
(b) means for selecting a subset of the cells based on the results of the measurements using the omni-directional beam pattern;
(c) means for performing measurements on signals received from the subset of cells using each of the directional beams;
(d) means for selecting a cell/beam combination having the strongest signal based on the results of the measurements performed using each of the directional beams; and
(e) means for registering with the selected cell using the selected beam as an active beam used for communicating with the selected cell.
13. In a wireless communication system including at least one wireless transmit/receive unit (WTRU) and a plurality of cells, the WTRU being configured to include a switched beam antenna for generating a plurality of directional beams and an omni-directional beam pattern, a cell selection method comprising:
(a) the WTRU performing measurements on signals received from the cells using the directional beams;
(b) the WTRU selecting a cell/beam combination having the strongest signal based on the results of the measurements performed in step (a); and
(c) the WTRU registering with the selected cell using the selected beam as an active beam used for communicating with the selected cell.
14. In a wireless communication system including a plurality of cells, a wireless transmit/receive unit (WTRU) comprising:
(a) a switched beam antenna for generating a plurality of directional beams and an omni-directional beam pattern;
(b) means for performing measurements on signals received from the cells using the directional beams;
(c) means for selecting a cell/beam combination having the strongest signal based on the results of the measurements performed using either directional beams; and
(d) means for registering with the selected cell using the selected beam as an active beam used for communicating with the selected cell.