Control channel placement method
First Claim
1. A control channel placement method applied to a wireless communication system, which wireless communication system having a base station having directional antennas that match placement angles of a plurality of sector cells performing communication in the TDMA-TDD mode with a plurality of terminal stations, and in which wireless communication system the up and down control channels for establishing communication by the base station with the terminal stations in each sector cell are placed in predetermined time slot positions within TDMA-TDD frames, the control channel placement method comprising:
- a reception level measurement step in which a reception level of each time slot extending over the TDMA-TDD frames corresponding to the number of sector cells of the base station is measured in each of the sector cells;
a time slot extraction step in which time slots in which control channels can be placed are extracted from among the time slots extending over the TDMA-TDD frames corresponding to the number of sector cells, using a result of the measurement of the reception level in the reception level measurement step when a first sector cell was measured, and a result of the measurement of the reception level in the reception level measurement step when a second sector cell in a position opposite to the first sector cell was measured from among the sector cells; and
a frame allocation step in which the TDMA-TDD frames are allocated for each sector cell such that those predetermined time slot positions in which control channels are placed, from among the time slots within the TDMA-TDD frames, are matched with time slots extracted in the time slot extraction step.
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Accused Products
Abstract
A first sector cell is set as an object for measurement (S101). Reception levels in each time slot in the number of TDMA-TDD frames is measured for the object cell (S102) and for all the cells (S103 and S105). The results of the measurement of a specific sector cell are added to the results of the measurement of a sector cell opposite the specific sector cell, and time slots in which control channels can be placed are extracted for each sector cell (S106 to S108). TDMA-TDD frames are then allocated such that the control channels of each sector cell coincide with time slots in which control channels can be placed (S109). In this way, control channels are placed in time slots such that a base station having a sector cell structure avoids interference from the same frequency.
53 Citations
11 Claims
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1. A control channel placement method applied to a wireless communication system, which wireless communication system having a base station having directional antennas that match placement angles of a plurality of sector cells performing communication in the TDMA-TDD mode with a plurality of terminal stations, and in which wireless communication system the up and down control channels for establishing communication by the base station with the terminal stations in each sector cell are placed in predetermined time slot positions within TDMA-TDD frames, the control channel placement method comprising:
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a reception level measurement step in which a reception level of each time slot extending over the TDMA-TDD frames corresponding to the number of sector cells of the base station is measured in each of the sector cells;
a time slot extraction step in which time slots in which control channels can be placed are extracted from among the time slots extending over the TDMA-TDD frames corresponding to the number of sector cells, using a result of the measurement of the reception level in the reception level measurement step when a first sector cell was measured, and a result of the measurement of the reception level in the reception level measurement step when a second sector cell in a position opposite to the first sector cell was measured from among the sector cells; and
a frame allocation step in which the TDMA-TDD frames are allocated for each sector cell such that those predetermined time slot positions in which control channels are placed, from among the time slots within the TDMA-TDD frames, are matched with time slots extracted in the time slot extraction step. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
a reception level remeasurement step for measuring, at regular intervals and for each of the sector cells, reception levels of time slots in which control channels have been placed in the frame allocation step; and
a frame reallocation step for performing the frame allocation step when a reception level measured in the reception level remeasurement step is equal to or greater than a predetermined threshold.
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7. The control channel placement method according to claim 6, wherein the frame allocation step performed in the frame reallocation step allocates the TDMA-TDD frame to a position shifted by one time slot towards the front or rear.
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8. The control channel placement method according to claim 6, wherein, in the reception level remeasurement step, the carrier to interference wave strength ratio is measured from the reception level and, in the frame reallocation step, the frame reallocation step is performed when the carrier to interference wave strength ratio measured in the reception level remeasurement step is equal to or greater than a predetermined threshold.
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9. The control channel placement method according to claim 8, wherein, in the frame reallocation step, if the carrier to interference wave strength ratio measured in the reception level remeasurement step continues to be equal to or greater than the predetermined threshold for a predetermined length of time, then it is determined that the time slot being measured is receiving interference obstruction and the frame allocation step is performed.
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10. The control channel placement method according to claim 6, wherein, in the reception level remeasurement step, the carrier to interference wave strength ratio is measured from the reception level when the time slot being measured is in a blocked state, and, in the frame reallocation step, the frame reallocation step is performed when the carrier to interference wave strength ratio measured in the reception level remeasurement step is equal to or greater than a predetermined threshold.
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11. The control channel placement method according to claim 10, wherein, in the reception level remeasurement step, an error detection ratio in an up control channel is measured as a reception level and, in the frame reallocation step, if the error detection ratio measured in the reception level remeasurement step is equal to or greater than a predetermined threshold the frame allocation step is performed.
Specification