초록 ▼

A control channel in a communication system transmits messages in a one or multiple-slot format. To assure consistency of a message, a content quality indicator is included in the message. Because a terminal receiving the message does not know the number of slots comprising the message, the terminal

A control channel in a communication system transmits messages in a one or multiple-slot format. To assure consistency of a message, a content quality indicator is included in the message. Because a terminal receiving the message does not know the number of slots comprising the message, the terminal performs blind format determination by testing hypothesis for all slot formats. Unfortunately, the content of certain control messages results in control messages that appear to be valid in a sense that, the computed CRC is equal to the interpreted CRC. Consequently, the mobile station declares a valid control message, and a false-alarm event occurs. Moreover, the same control messages always result in the same false-alarm events. To prevent such repetitive incorrect determination, the content of the message is scrambled by a time-dependent scrambling sequence before transmission. Re-generating the scrambling sequence, and performing inverse to the scrambling then unscrambles the received message.

대표청구항 ▼

1. A method for scrambling information bits in a communications system, comprising: determining a scrambling sequence based on a metric of system time, wherein said determining a scrambling sequence includes determining the metric based on a subinterval of a system time interval of a control channel

1. A method for scrambling information bits in a communications system, comprising: determining a scrambling sequence based on a metric of system time, wherein said determining a scrambling sequence includes determining the metric based on a subinterval of a system time interval of a control channel in which the information bits of a control message are to be transmitted; andscrambling the information bits of the control message with the determined scrambling sequence in accordance with the metric. 2. The method of claim 1, wherein said determining the metric in accordance with the subinterval of the system time interval in which the information bits are to be transmitted comprises: determining the metric in accordance with a first subinterval of the system time interval. 3. The method of claim 1, wherein said determining the scrambling sequence in accordance with the metric of system time comprises: performing mapping of the metric on the scrambling sequence. 4. The method of claim 1, wherein said scrambling information bits with the scrambling sequence comprises: performing an exclusive-OR of the information bits with the scrambling sequence. 5. A method for unscrambling information bits in a communications system, comprising: determining an unscrambling sequence based on a metric of system time, wherein said determining an unscrambling sequence includes determining the metric based on a first subinterval of a system time interval of a control channel preceding a second subinterval of the system time interval by a pre-determined number of subintervals, the second subinterval including information bits of a control message transmitted on the control channel to be unscrambled; andunscrambling the information bits of the control message transmitted on the control channel with the determined unscrambling sequence in accordance with the metric. 6. The method as claimed in claim 5, wherein said determining the metric in accordance with a first subinterval of the system time interval preceding a second subinterval of system time interval by a pre-determined number of subintervals comprises: determining the first subinterval of the system time interval preceding the second, subinterval of the system time interval by one subinterval. 7. The method as claimed in claim 5, wherein said determining the unscrambling sequence in accordance with the metric comprises: performing mapping of the metric on the unscrambling sequence. 8. The method of claim 5, wherein said unscrambling information bits with the scrambling sequence comprises: performing an exclusive-OR of the information bits with the unscrambling sequence. 9. An apparatus for scrambling information bits in a communications system, the apparatus comprising: means for determining a scrambling sequence based on a metric of system time, wherein said determining a scrambling sequence includes determining the metric based on a subinterval of a system time interval of a control channel in which the information bits of a control message are to be transmitted; andmeans for scrambling the information bits of the control message with the determined scrambling sequence in accordance with the metric. 10. The apparatus of claim 9, wherein said means for determining the metric in accordance with the subinterval of the system time interval in which the information bits are to be transmitted comprises: means for determining the metric in accordance with a first subinterval of the system time interval. 11. The apparatus of claim 9, wherein said means for determining the scrambling sequence in accordance with a metric of system time comprises: means for performing mapping of the metric on the scrambling sequence. 12. The apparatus of claim 9, wherein said means for scrambling information bits with the scrambling sequence comprises; means for performing an exclusive-OR of the information bits with the scrambling sequence. 13. An apparatus for unscrambling information bits in a communications system, the apparatus comprising: means for determining an unscrambling sequence based on a metric of system time, wherein said determining an unscrambling sequence includes determining the metric based on a first subinterval of a system time interval of a control channel preceding a second subinterval of the system time interval by a pre-determined number of subintervals, the second subinterval including information bits of a control message transmitted on the control channel to be unscrambled; andmeans for unscrambling the information bits of the control message transmitted on the control channel with the determined unscrambling sequence in accordance with the metric. 14. The apparatus as claimed in claim 13, wherein said means for determining the metric in accordance with a first subinterval of the system time interval preceding a second subinterval of system time interval by a pre-determined number of subintervals comprises: means for determining the first subinterval of the system time interval preceding the second subinterval of the system time interval by one subinterval. 15. The apparatus as claimed in claim 13, wherein said means for determining the unscrambling sequence in accordance with the metric comprises: means for performing mapping of the metric on the unscrambling sequence. 16. The apparatus of claim 13, wherein said means for unscrambling information bits with the scrambling sequence comprises: means for performing an exclusive-OR of the information bits with the unscrambling sequence. 17. An apparatus for scrambling information bits in a communications system, the apparatus comprising: an electronic processor programmed to provide: a sequence generator for determining a scrambling sequence based on a metric of system time, wherein the sequence generator determines the metric based on a subinterval of a system time interval of a control channel in which the information bits of a control message are to be transmitted; anda scrambler for scrambling the information bits of the control message with the determined scrambling sequence in accordance with the interval of the channel. 18. An apparatus for unscrambling information bits in a communications system, the apparatus comprising: an electronic processor programmed to provide: a sequence generator for determining an unscrambling sequence based on a first subinterval of a system time interval of a control channel preceding a second subinterval of the system time interval by a predetermined number of subintervals, the second subinterval including information bits of a control message transmitted on the control channel to be unscrambled; andan unscrambler for unscrambling the information bits of the control message transmitted on the control channel with the determined unscrambling sequence in accordance with the unscrambling sequence. 19. An article, comprising: a non-transitory computer-readable medium having stored thereon code executable by at least one electronic processor to: determine a scrambling sequence based on a metric of system time, wherein said determining a scrambling sequence includes determining the metric based on a subinterval of a system time interval of a control channel in which the information bits of a control message are to be transmitted; andscramble the information bits of the control message with the determined scrambling sequence in accordance with the metric. 20. An article, comprising: a non-transitory computer-readable medium having stored thereon code executable by at least one electronic processor to: determine an unscrambling sequence based on a metric of system time, wherein said determining an unscrambling sequence includes determining the metric based on a first subinterval of a system time interval of a control channel preceding a second subinterval of the system time interval by a pre-determined number of subintervals, the second subinterval including information bits of a control message transmitted on the control channel to be unscrambled; andunscramble the information bits of the control message transmitted on the control channel with the determined unscrambling sequence in accordance with the metric.