Method and system for uniquely identifying control channel time slots

• US 5,199,031 A
• Filed: 02/28/1991
• Issued: 03/30/1993
• Est. Priority Date: 08/31/1990
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Dahlin, Jan E. .ANG. S.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): KIZOU, HASSAN
• Application Number:
  US07/662,414
• Time in Patent Office: 761 Days
• Field of Search: 370/95.1, 370/95.3, 370/85.7, 370/79, 370/110.1, 370/105.2, 370/105.4, 455/33.1, 455/34.1, 455/34.2, 455/53.1, 455/54.1, 379/58, 379/59, 379/60, 379/63
• US Class Current: 370/329
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence
• CPC Class Codes: H04L 7/041 using special codes as synchronising signal
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365

Abstract

A method and system in which the control channels of an associated base station directly correspond to certain time slots of a radio channel frame, which also includes time slots being utilized for traffic channels. The time slots being utilized as control channels are marked with uniquely defined control channel indicators which include unique Sync Words and unique control channel identification words. The mobile station recognizes the uniquely defined control channel indicators and identifies those particular time slots as control channels so as to distinguish from the time slots which are not being used as control channels.

Claims

1. A system for utilizing certain time slots of a radio channel frame as communication channels, each time slot capable of being used for transmitting message signals between a mobile station and a base station in a cellular telephone network, said system comprising:

message signal generating means for generating message signals to be transmitted in said time slots of said frame as a series of binary bits;

synchronization word generating means for generating time slot synchronization words which are associated with each of said time slots, each time slot including channel indication information for indicating whether a time slot is a first type of channel or a second type of channel;

frame producing means for producing a frame, which includes a plurality of said time slots, by allotting to each of said time slots a message signal and an associated synchronization word;

transmitting means for transmitting said frame;

receiving means for receiving said transmitted frame;

detecting means for detecting said channel indication information; and

determining means determining whether each of said time slots is to be utilized as a traffic channel or a control channel in response to detection of either said first type of channel or said second type of channel.

2. A system according to claim 1, wherein said first type of channel is a voice/data traffic channel.

3. A system according to claim 1, wherein said second type of channel is a control channel.

4. A system according to claim 1, wherein said channel indication information includes at least one unique synchronization word for designating that said associated time slot is to be used as a control channel.

5. A system according to claim 1, wherein said channel indication information includes at least one control channel identification word defined by at least some of said binary bits other than voice/data bits.

6. A method for utilizing certain time slots of a frame as communication channels, each time slot being used for transmitting message signals between a mobile station and a base station in a cellular telephone network, said method comprising the steps of:

generating message signals to be transmitted in said time slots of said frame;

generating synchronization words which are associated with each of said time slots, each time slot having associated therewith channel indication information for indicating whether a time slot is a first type of channel or a second type of channel;

producing a frame, which includes a plurality of said time slots, by allotting to each of said time slots a message signal and an associated synchronization word;

transmitting said frame from one of said base and mobile stations;

receiving said frame at the other of said base and mobile station;

detecting said channel indication information; and

determining whether each of said time slots should be utilized as a traffic channel or a control channel in response to said detecting step.

7. A method for designating time slots of a frame, which includes time slots being utilized for traffic channels and control channels, said frames utilized for transmitting message signals between a base station and a mobile station in a cellular telephone system, comprising the steps of:

generating at least one unique control channel identification word for designating at least one time slot as a control channel;

producing a frame having at least one time slot with an associated control channel identification word combined therewith;

detecting said at least one time slot with said associated control channel identification word; and

utilizing said detected at least one time slot with said associated control channel identification word as a control channel.

8. The method according to claim 7, wherein said at least one control channel identification word is generated using preestablished control fields within each of said time slots.

9. The method according to claim 8, wherein said generating step generates two unique control channel identification words that both designate an associated time slot as a control channel and that individually convey additional message information.

10. A system for utilizing a plurality of time slots of a radio channel frame as communication channels, each time slot capable of being used for transmitting message signals between a mobile radio station and a base station in a cellular telephone network, said system comprising:

message signal generating means for generating message signals to be transmitted in said time slots of said frame;

synchronization word generating means for generating a plurality of synchronization words of a first type which are uniquely associated with a plurality of said time slots and for generating a plurality of synchronization words of a second type which are uniquely associated with at least one of said time slots;

frame producing means for producing said radio channel frame by allotting to a plurality of said time slots in said frame a first type of message signal and an associated synchronization word of said first type and by allotting to at least one of said time slots a second type of message signal and an associated synchronization of said second type;

transmitting means for transmitting said frame;

receiving means for receiving said transmitted frame;

detecting means for detecting the type of synchronization word associated with each of said time slots; and

determining means for determining whether each of said time slots is to be utilized as a traffic channel or a control channel in response to a detection of a synchronization word either of said first type or said second type, said synchronization word of said first type of message signals designating a time slot as a channel transmitting said first type of message signal and said synchronization word of said second type designating a time slot as a channel transmitting said second type of message signal.

11. A system according to claim 10, wherein said channel transmitting said first type of message signal is a voice/data traffic channel and said channel transmitting said second type of message signal is a control channel.

12. A system according to claim 10, wherein said frame includes six time slots to which are allotted three communication channels for transmitting said message signals.

13. A system according to claim 12, wherein each of said six time slots of said frame may be associated with said synchronization words of said first type and four of said six time slots of said frame may be associated also with said synchronization word of said second type.

14. A system according to claim 13, wherein each of said four time slots may be designated as either a control channel or a voice/data channel depending on the type of synchronization word detected by said detecting means and the remaining two time slots may be designated only as voice/data channels.

15. A system according to claim 14, wherein said synchronization words of said first type include six unique synchronization words and said synchronization words of said second type include two unique synchronization words for a total of eight unique synchronization words associated with said frame.

16. In a digital cellular radio telephone system of the type in which information is communicated between base stations of the system and mobile telephone units in frames, with each frame being divided into a plurality of time slots that correspond to respective digital communication channels, a method for enabling said digital communication channels to be alternatively and selectively used as traffic channels for the communication of voice and data information or control channels for the communication of control information, comprising the steps of:

establishing a set of synchronization words, each synchronization word being associated with one of the time slots in a frame, with the total number of synchronization words in said set being greater than the number of time slots in a frame, so that at least one time slot has two synchronization words associated therewith;

dividing said set of synchronization words into words of a first type and words of a second type, with each of the synchronization words of said first type being uniquely associated with a respective one of the time slots in a frame, and the synchronization words of said second type being uniquely associated with respective ones of the time slots in a frame;

transmitting segments of information in respective time slots of a frame; and

transmitting one of said synchronization words with each segment of information, said one synchronization word being associated with the time slot in which the segment of information is transmitted and being of said first type when the segment of information is voice or data information and being of said second type when the segment of information is control information.

17. The method of claim 16, wherein the synchronization words in said set have low correlation with each other regardless of whether they are in-phase or out-of-phase with each other.

18. The method of claim 17, wherein each synchronization word in said set exhibits low correlation with itself when out-of-phase.

19. The method of claim 16, wherein each frame contains six time slots and said set of synchronization words contains at least eight synchronization words, with six of said synchronization words being of said first type and two of said synchronization words being of said second type, so that at least two of the time slots in a frame can be alternately used for the transmission of voice information or control information.

20. A system for utilizing a plurality of time slots of a radio channel frame as communication channels, each time slot capable of being used for transmitting message signals between a mobile radio station and a base station in a cellular telephone network, said system comprising:

message signal generating means for generating message signals to be transmitted in said time slots of said frame;

word generating means for generating a plurality of time slot synchronization words which are uniquely associated with a plurality of said time slots and for generating at least one control channel identification word which is uniquely associated with at least one of said time slots, wherein one of said time slot synchronization words and said at least one control channel identification word are combined to generate an extended synchronization word;

frame producing means for producing said radio channel frame by allotting to a plurality of said time slots in said frame a first type of message signal and an associated time slot synchronization word and by allotting to at least one of said time slots a second type of message signal and an associated extended synchronization word;

transmitting means for transmitting said frame;

receiving means for receiving said transmitted frame;

detecting means for detecting the synchronization word associated with each of said time slots; and

determining means for determining whether each of said time slots is to be utilized as a traffic channel or a control channel in response to said detection means, wherein detection of said time slot synchronization word determines that a time slot is a traffic channel and detection of said extended synchronization word determines that a time slot is a control channel.

21. A system according to claim 20, wherein said frame includes six time slots to which are allotted three communication channels for transmitting said message signals.

22. A system according to claim 21, wherein each of said six time slots of said frame may be associated with said time slot synchronization words and four of said six time slots of said frame may be associated also with said extended synchronization words.

23. A system according to claim 20, wherein said control channel identification word includes some portion of the control information transmitted in said message signals.

24. A system according to claim 20, wherein said word generating means generates two control channel identification words each of which designate an associated time slot as a control channel and which convey different control information.