Communication control device and method for CDMA communication system

• US 6,577,608 B1
• Filed: 08/17/1999
• Issued: 06/10/2003
• Est. Priority Date: 08/17/1998
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jeong-Gu, Moon, Hi-Chan, Kim, Young Ky, Ahn, Jae-Min
• Primary Examiner(s): VUONG, QUOCHIEN B
• Application Number:
  US09/375,944
• Time in Patent Office: 1,393 Days
• Field of Search: 370/208, 370/311, 370/320, 370/335, 370/342, 370/441, 455/343, 455/522, 455/422, 455/574
• US Class Current: 370/311
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels

Abstract

A device and method for communicating a common channel message in a CDMA communication system. The device comprises a base station transmitter and a common channel transmitter. The base station transmitter includes a specific channel transmitter for outputting a channel signal at a second transmission power level for a predetermined time duration and otherwise outputting the channel signal at a first transmission power level. The common channel transmitter transmits a common channel message at an assigned slot duration. A power supply voltage is provided to the receiver of the mobile station for the predetermined time duration and the assigned slot duration to enable the receiver. The power supply voltage to the receiver is otherwise disengaged from the power supply so as to allow the receiver to operate in a sleep mode.

Claims

1. A device for communicating a common channel message in a code division multiple access (CDMA) communication system, comprising:

a base station transmitter including a specific channel transmitter for outputting a channel signal on a specific channel at a second transmission power level for a predetermined time duration and otherwise outputting the channel signal at a first transmission power level, and a common channel transmitter for transmitting a common channel message at an assigned slot duration; and

a receiver of a mobile station, wherein a power supply voltage is provided to the receiver at said predetermined time duration before said assigned slot duration and at said assigned slot duration to enable the receiver, and wherein the power supply voltage to the receiver is otherwise disengaged whereby the receiver operates in a sleep mode.

2. The device as claimed in claim 1, wherein said receiver further comprises a searcher which is enabled when said receiver is enabled to store the received signal on the specific channel, and for estimating the received signal on the specific channel to perform channel acquisition.

3. The device as claimed in claim 2, wherein the step of estimating the received signal by said searcher comprises sampling the receiving signal by said searcher when said receiver is enabled, storing the sampled signal, searching the stored signal of the specific channel during the sleep mode and performing sector selecting and finger assignment in accordance with the search results.

4. The device as claimed in claim 3, wherein the searcher comprises:

a memory for storing the signal on the specific channel;

a despreader for despreading the signal on the specific channel, output from the memory;

an energy calculator for calculating the energy of the despread signal; and

a channel estimator for estimating a channel from an output of the energy calculator.

5. The device as claimed in claim 2, wherein the specific channel is a pilot channel and the common channel is a paging channel.

6. The device as claimed in claim 5, wherein a pilot channel transmitter of the base station generates a pilot channel signal for transmitting an increased transmission power at the predetermined time using at least two spreading codes, and wherein said searcher for performing despreading using the spreading codes at the predetermined time to perform searching.

7. The device as claimed in claim 6, wherein the pilot channel received at said second transmission power as one to four symbols.

8. A device for communicating a common channel message in a CDMA communication system, comprising:

a base station transmitter including;

a pilot channel transmitter for outputting a specific channel signal at a second transmission power for a predetermined time duration and otherwise outputting the channel signal at a first transmission power level; and

a paging channel transmitter for transmitting a paging channel message at an assigned slot duration; and

a mobile station receiver comprising;

a radio frequency (RF) receiver being enabled for said predetermined time duration and for said assigned slot duration, and otherwise operating in a sleep mode;

a searcher enabled when said RF receiver is enabled, for storing the received pilot signal and searching the receiver pilot signal to perform channel acquisition; and

fingers enabled at the assigned slot duration, for processing a received message.

9. The device as claimed in claim 8, wherein the step of searching the received pilot signal comprises sampling the receiving signal by said searcher when said receiver is enabled, storing the sampled signal, searching the stored signal of the specific channel during the sleep mode and performing sector selecting and finger assignment in accordance with the search results.

10. The device as claimed in claim 9, wherein the searcher comprises:

a memory for storing the signal on the specific channel;

a despreader for despreading the signal on the specific channel, output from the memory;

an energy calculator for calculating energy of the despread signal; and

a channel estimator for estimating a channel from an output of the energy calculator.

11. The device as claimed in claim 10, wherein a pilot channel transmitter of the base station generates a pilot signal using a specific orthogonal code assigned to a pilot channel when transmitting the pilot signal at the first transmission power level, and further generates a pilot signal using at least two orthogonal codes when transmitting the pilot signal at the second transmission power level;

wherein the despreader of the mobile station despreads a received pilot channel signal using the at least two orthogonal codes.

12. A method for communicating a common channel message in a CDMA communication system, wherein a base station outputs a channel signal at a second transmission power level for a predetermined time duration and otherwise outputs the channel signal at a first transmission power level, the method comprising the steps of:

providing a power supply voltage to a receiver of a mobile station for said predetermined time duration before a slot duration assigned to receive the common channel message and for the assigned slot duration, causing said receiver to exit a sleep mode; and

cutting off the power supply voltage at time intervals other than said predetermined time duration and said slot duration to perform the sleep mode.

13. The method as claimed in claim 12, further comprising the step of sampling a received pilot signal having the second transmission power, storing the sampled signal, searching the stored pilot channel signal during the sleep mode, to perform channel acquisition, and performing sector selecting and finger assignment according to the search results.

14. A method for communicating a common channel message in a CDMA communication system, wherein a base station outputs a pilot signal at a second transmission power for a predetermined time duration and otherwise outputs the pilot signal at a first transmission power level, the method comprising the steps of:

providing a power supply voltage to a receiver of a mobile station for said predetermined time duration, said predetermined time duration occurring prior to a slot duration pre-assigned to receive a common channel message, to release a sleep mode and store the received pilot signal, and re-enter the sleep mode after receipt of the pilot channel signal;

searching the stored pilot signal during the sleep mode, and performing sector selecting and finger assignment according to the channel acquisition results; and

providing a power supply voltage to said receiver at the assigned slot duration to exit the sleep mode, receiving the common channel message, enabling the assigned fingers to process the received common channel message, and re-entering the sleep mode after processing the common channel message.

15. A device for transmitting a common channel message for a base station in a CDMA communication system, comprising:

a pilot channel transmitter for outputting a pilot signal at a second transmission power level for a predetermined time duration and otherwise outputting the pilot signal with first transmission power at other time duration;

a paging channel transmitter for transmitting a paging message at an assigned slot duration; and

a quick paging channel transmitter for transmitting a quick paging channel message indicating one of existence and non-existence of the common channel message prior to the assigned slot duration.

16. The device as claimed in claim 15, wherein the pilot channel transmitter comprises:

a first spreader for spreading the pilot signal with a first orthogonal code to generate a pilot signal having the first transmission power level;

a second spreader for spreading the pilot signal with at least one orthogonal code other than the first orthogonal code to generate a pilot signal, the second spreader being enabled on a slot unit basis; and

an adder for adding outputs of the first and second spreaders to generate a pilot signal.

17. A device for receiving a common channel message for a mobile station in a CDMA communication system, wherein a base station outputs a pilot signal at a second transmission power level for a predetermined time duration and otherwise outputs the pilot signal at a first transmission power level, and transmits a quick paging message representing one of an existence and non-existence of a paging message before a slot duration assigned to transmit the common channel message, the device comprising:

a receiver which is provided with a power supply voltage for time durations including said predetermined time duration, a quick paging message duration and an assigned slot duration, to perform a receiving operation, said receiver being otherwise disengaged from the power supply voltage to re-enter a sleep mode;

a searcher for storing the pilot signal received at the second transmission power level, and searching the pilot signal to perform channel acquisition; and

fingers for receiving the quick paging channel message to determine one of an existence or non-existence of the assigned slot, the fingers being enabled only when the message is received to process the received message.

18. A method for transmitting a message on a common channel for a base station in a CDMA communication system, comprising the steps of:

transmitting a pilot signal with transmission power higher than a normal transmission power at predetermined periods;

transmitting a quick paging channel message indicating one of the existence and non-existence of the common channel message before a paging slot duration assigned to a specific mobile station; and

transmitting a paging message at the assigned paging slot duration.

19. A method for receiving a common channel message for a mobile station in a CDMA communication system, wherein a base station outputs a pilot signal at a second transmission power level for a predetermined time duration and otherwise outputs the pilot signal at a first transmission power level, and transmits a quick paging message representing one of a an existence and non-existence of a paging message before a slot duration assigned to transmit the common channel message, the method comprising the steps of:

providing a power supply voltage to an RF receiver for said predetermined time duration, to receive and store the pilot signal, and disengaging the power supply voltage to the RF receiver to search the stored pilot signal in a sleep mode and perform channel acquisition;

exiting the sleep mode for a duration defined by the transmission time of the quick paging channel message, re-entering the sleep mode, and analyzing the received quick paging message to determine one of an existence and non-existence of the assigned slot; and

when the message exists, exiting the sleep mode at the assigned slot duration, to process the received message and then proceeds to the sleep mode, and otherwise, re-entering the sleep mode at the assigned slot duration.