초록 ▼

To transmit data in a manner to mitigate the deleterious effects of delay spread, the expected coverage areas for multiple transmissions to be sent in multiple time slots are initially determined. Cyclic prefix lengths for these transmissions are selected based on the expected coverage areas. The cy

To transmit data in a manner to mitigate the deleterious effects of delay spread, the expected coverage areas for multiple transmissions to be sent in multiple time slots are initially determined. Cyclic prefix lengths for these transmissions are selected based on the expected coverage areas. The cyclic prefix length for each transmission may be selected from among a set of allowed cyclic prefix lengths based on the expected coverage area for that transmission, the pilot staggering used for the transmission, and so on. For example, a shorter cyclic prefix length may be selected for each local transmission, and a longer cyclic prefix length may be selected for each wide-area transmission. The selected cyclic prefix lengths may be signaled to the terminals. The transmissions are processed (e.g., OFDM modulated) based on the selected cyclic prefix lengths. The cyclic prefix lengths may be selected periodically, e.g., in each super-frame.

대표청구항 ▼

1. An apparatus comprising: a controller to determine expected coverage areas for a plurality of transmissions to be sent in a plurality of time slots, to select cyclic prefix lengths for the plurality of transmissions based on the expected coverage areas, and to select a staggered pilot from among

1. An apparatus comprising: a controller to determine expected coverage areas for a plurality of transmissions to be sent in a plurality of time slots, to select cyclic prefix lengths for the plurality of transmissions based on the expected coverage areas, and to select a staggered pilot from among a plurality of staggered pilots based on the expected coverage areas; anda modulator to process the plurality of transmissions based on the selected cyclic prefix lengths and to process the selected staggered pilot. 2. The apparatus of claim 1, wherein the controller determines the expected coverage areas and selects the cyclic prefix lengths in each time interval of a predetermined duration. 3. The apparatus of claim 1, wherein the controller selects a cyclic prefix length from among a plurality of cyclic prefix lengths for each of the plurality of transmissions based on an expected coverage area for the transmission. 4. The apparatus of claim 1, wherein the controller determines whether each of the plurality of transmissions is a local transmission or a wide-area transmission. 5. The apparatus of claim 4, wherein the controller selects a first cyclic prefix length for each local transmission among the plurality of transmissions and selects a second cyclic prefix length for each wide-area transmission among the plurality of transmissions, wherein the second cyclic prefix length is longer than the first cyclic prefix length. 6. The apparatus of claim 1, wherein the controller selects the cyclic prefix lengths for the plurality of transmissions further based on a frequency division multiplexed (FDM) pilot sent with the plurality of transmissions. 7. The apparatus of claim 1, wherein the modulator generates orthogonal frequency division multiplexing (OFDM) symbols for each of the plurality of transmissions based on a cyclic prefix length selected for the transmission. 8. A method of transmitting data in a wireless communication system, comprising: determining expected coverage areas for a plurality of transmissions to be sent in a plurality of time slots;selecting cyclic prefix lengths for the plurality of transmissions based on the expected coverage areas;selecting a staggered pilot from among a plurality of staggered pilots based on the expected coverage areas;processing the plurality of transmissions based on the selected cyclic prefix lengths; andprocessing the selected staggered pilot. 9. The method of claim 8, further comprising: performing the determining the expected coverage areas and the selecting the cyclic prefix lengths in each time interval of a predetermined duration. 10. The method of claim 8, wherein the selecting the cyclic prefix lengths for the plurality of transmissions comprises determining whether each of the plurality of transmissions is a local transmission or a wide-area transmission,selecting a first cyclic prefix length for each local transmission among the plurality of transmissions, andselecting a second cyclic prefix length for each wide-area transmission among the plurality of transmissions, wherein the second cyclic prefix length is longer than the first cyclic prefix length. 11. The method of claim 8, wherein the processing the plurality of transmissions based on the selected cyclic prefix lengths comprises generating orthogonal frequency division multiplexing (OFDM) symbols for each of the plurality of transmissions based on a cyclic prefix length selected for the transmission. 12. An apparatus comprising: means for determining expected coverage areas for a plurality of transmissions to be sent in a plurality of time slots;means for selecting cyclic prefix lengths for the plurality of transmissions based on the expected coverage areas;means for selecting a staggered pilot from among a plurality of staggered pilots based on the expected coverage areas;means for processing the plurality of transmissions based on the selected cyclic prefix lengths; andmeans for processing the selected staggered pilot. 13. The apparatus of claim 12, further comprising: means for determining the expected coverage areas and selecting the cyclic prefix lengths in each time interval of a predetermined duration. 14. The apparatus of claim 12, wherein the means for selecting the cyclic prefix lengths for the plurality of transmissions comprises means for determining whether each of the plurality of transmissions is a local transmission or a wide-area transmission,means for selecting a first cyclic prefix length for each local transmission among the plurality of transmissions, andmeans for selecting a second cyclic prefix length for each wide-area transmission among the plurality of transmissions, wherein the second cyclic prefix length is longer than the first cyclic prefix length. 15. The apparatus of claim 12, wherein the means for processing the plurality of transmissions based on the selected cyclic prefix lengths comprises means for generating orthogonal frequency division multiplexing (OFDM) symbols for each of the plurality of transmissions based on a cyclic prefix length selected for the transmission. 16. A method of transmitting data in a wireless communication system, comprising: selecting a cyclic prefix length for a data transmission from among a plurality of cyclic prefix lengths based on a maximum expected delay spread for the data transmission;selecting a staggered pilot from among a plurality of staggered pilots based on the maximum expected delay spread;processing the data transmission based on the selected cyclic prefix length; andprocessing the selected staggered pilot. 17. The method of claim 16, further comprising: estimating the maximum expected delay spread for the data transmission based on a type of the data transmission. 18. The method of claim 16, further comprising: estimating the maximum expected delay spread for the data transmission based on an expected coverage area for the data transmission. 19. The method of claim 16, wherein the selecting the cyclic prefix length comprises selecting a first cyclic prefix length from among the plurality of cyclic prefix lengths if the data transmission is a local transmission, andselecting a second cyclic prefix length from among the plurality of cyclic prefix lengths if the data transmission is a wide-area transmission, wherein the second cyclic prefix length is longer than the first cyclic prefix length. 20. The method of claim 16, wherein the processing the data transmission based on the selected cyclic prefix length comprises generating orthogonal frequency division multiplexing (OFDM) symbols for the data transmission based on the selected cyclic prefix length. 21. The method of claim 16, further comprising: broadcasting the data transmission to a plurality of receivers. 22. The method of claim 16, further comprising: sending the data transmission to a specific receiver. 23. An apparatus comprising: a controller to receive signaling for at least one cyclic prefix length selected for at least one transmission sent in at least one time slot, wherein the at least one cyclic prefix length is selected based on an expected coverage area for the at least one transmission;a demodulator to receive and process the at least one transmission based on the at least one cyclic prefix length;a channel estimator to receive a staggered pilot transmitted with the at least one transmission and to derive a channel estimate based on the received staggered pilot, wherein the staggered pilot is selected based on the expected coverage area for the at least one transmission; anda detector to perform detection on the at least one transmission with the channel estimate. 24. The apparatus of claim 23, wherein each of the at least one transmission is a local transmission or a wide-area transmission, wherein a first cyclic prefix length is selected for each local transmission, wherein a second cyclic prefix length is selected for each wide-area transmission, and wherein the second cyclic prefix length is longer than the first cyclic prefix length. 25. The apparatus of claim 23, wherein the controller receives the signaling for the at least one cyclic prefix length in each of a plurality of time intervals, each time interval having a predetermined duration. 26. The apparatus of claim 23, wherein the demodulator receives orthogonal frequency division multiplexing (OFDM) symbols for each of the at least one transmission and removes cyclic prefixes in the received OFDM symbols for each transmission based on a cyclic prefix length selected for the transmission. 27. A method of receiving data in a wireless communication system, comprising: receiving signaling for at least one cyclic prefix length selected for at least one transmission sent in at least one time slot, wherein the at least one cyclic prefix length is selected based on an expected coverage area for the at least one transmission;processing the at least one transmission based on the at least one cyclic prefix length;receiving a staggered pilot transmitted with the at least one transmission, wherein the staggered pilot is selected based on the expected coverage area for the at least one transmission;deriving a channel estimate based on the received staggered pilot; andperforming detection on the at least one transmission with the channel estimate. 28. The method of claim 27, further comprising: performing the receiving the signaling for the at least one cyclic prefix length and the processing the at least one transmission in each of a plurality of time intervals, each time interval having a predetermined duration. 29. The method of claim 27, wherein the processing the at least one transmission comprises receiving orthogonal frequency division multiplexing (OFDM) symbols for each of the at least one transmission, andremoving cyclic prefixes in the received OFDM symbols for each transmission based on a cyclic prefix length selected for the transmission. 30. An apparatus comprising: means for receiving signaling for at least one cyclic prefix length selected for at least one transmission sent in at least one time slot, wherein the at least one cyclic prefix length is selected based on expected coverage area for the at least one transmission;means for processing the at least one transmission based on the at least one cyclic prefix length;means for receiving a staggered pilot transmitted with the at least one transmission, wherein the staggered pilot is selected based on the expected coverage area for the at least one transmission;means for deriving a channel estimate based on the received staggered pilot; andmeans for performing detection on the at least one transmission with the channel estimate. 31. The apparatus of claim 30, further comprising: means for receiving the signaling for the at least one cyclic prefix length and for processing the at least one transmission in each of a plurality of time intervals, each time interval having a predetermined duration. 32. The apparatus of claim 30, wherein the means for processing the at least one transmission comprises means for receiving orthogonal frequency division multiplexing (OFDM) symbols for each of the at least one transmission, andmeans for removing cyclic prefixes in the received OFDM symbols for each transmission based on a cyclic prefix length selected for the transmission. 33. A computer-program product for transmitting data in a wireless communication system, the computer-program product comprising a computer-readable medium having instructions thereon, the instructions comprising: code for determining expected coverage areas for a plurality of transmissions to be sent in a plurality of time slots;code for selecting cyclic prefix lengths for the plurality of transmissions based on the expected coverage areas;code for selecting a staggered pilot from among a plurality of staggered pilots based on the expected coverage areas;code for processing the plurality of transmissions based on the selected cyclic prefix lengths; andcode for processing the selected staggered pilot.