GB2301749A - Allocation of signalling and traffic slots in TDM communication system - Google Patents

Allocation of signalling and traffic slots in TDM communication system Download PDF

Info

Publication number
GB2301749A
GB2301749A GB9511131A GB9511131A GB2301749A GB 2301749 A GB2301749 A GB 2301749A GB 9511131 A GB9511131 A GB 9511131A GB 9511131 A GB9511131 A GB 9511131A GB 2301749 A GB2301749 A GB 2301749A
Authority
GB
United Kingdom
Prior art keywords
signalling
frame
slot
communications
slots
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9511131A
Other versions
GB2301749B (en
GB9511131D0 (en
Inventor
Gareth Ian Owen
Steven Thomas Valentine
Gary Aitkenhead
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Motorola Solutions UK Ltd
Original Assignee
Motorola Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Motorola Ltd filed Critical Motorola Ltd
Priority to GB9511131A priority Critical patent/GB2301749B/en
Publication of GB9511131D0 publication Critical patent/GB9511131D0/en
Publication of GB2301749A publication Critical patent/GB2301749A/en
Application granted granted Critical
Publication of GB2301749B publication Critical patent/GB2301749B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H04W72/044—Wireless resource allocation based on the type of the allocated resource
    • H04W72/0446—Resources in time domain, e.g. slots or frames
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/12—Arrangements providing for calling or supervisory signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/16—Time-division multiplex systems in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted
    • H04J3/1682—Allocation of channels according to the instantaneous demands of the users, e.g. concentrated multiplexers, statistical multiplexers

Abstract

A Time division Multiplexed communications system has a frame divided into traffic and signalling information. The slot allocated to a communications unit in the signalling frame is independent from the respective slot allocated in the traffic frame. The system is also capable of switching between trunked slow associated control channel (TSACCH) and normal slow associated control channel (SACCH) depending upon whether the amount of signalling messages to be sent exceeds the capacity of a particular slot.

Description

COMMUNICATIONS SYSTEM AND METHOD OF OPERATION Field of the Invention This invention relates to communications systems and, in particular, to time division multiplexed communications systems. The invention is applicable to, but not limited to, communications systems having traffic and signalling frames.
Background of the Invention In many digital radio communications systems it is desirable to communicate traffic and signalling information between communications units. To provide both traffic and signalling operations, a communications system typically divides its communications resource into either independent frequency channels, as with a frequency division multiple access (FDMA) scheme, or independent time periods (frames), as with time division multiple access (TDMA) schemes.
The communications resource of a digital radio communications system is divided into time multi-frames, each time multi-frame being divided into a number of time frames and each time frame divided into a number of slots. A particular slot on all frames is allocated for a period of time for communications between users. Within a multi-frame the allocated slot is used either for traffic or signalling purposes.
In mobile radio systems such as the Trans European Trunked Radio (TETRA) system associated signalling, (e.g. short data service (SDS) messages, late entry signalling messages) is transmitted to subscriber units involved in calls, during the allocated signalling slot in the associated signalling frame. In TETRA, the associated signalling frame is allocated to frame eighteen of an eighteen frame TDMA structure and broadcast network information is sent on the broadcast network channel (BNCH) and broadcast synchronisation information is sent on the broadcast synchronisation channel (BSCH). Signalling messages transmitted on the associated signalling frame are transmitted as broadcast information, individually, group addressed.
Sub-slots of the uplink signalling frame, i.e. signalling messages from a moblie radio unit to a base radio unit, are usually reserved for acknowledgements to individually addressed down-link signalling messages.
However, any subscriber involved in a call may transmit or receive signalling messages in its allocated slot in the signalling frame (frame 18).
A problem occurs in a busy system whereby the associated signalling, to and from subscribers involved in a specific call, is too great to be sent or received on the one slot allocated for that call. In this situation, signalling messages, sent to and from subscribers involved in a call, are delayed by as much as a number of seconds until there is an opportunity for transmission.
This is especifically true when a priority monitor function is implemented in a system.
Thus, it is desirable to have an improved method for transmitting signalling information to communications units whilst the communications units are involved in a call. It would also be beneficial to have an improved traffic and signalling frame structure for a time division multiplexed communications system.
Summarv of the Invention In a first aspect of the present invention, a time division multiplexed communications system is provided. The communications system comprises time frames divided into traffic frames and signalling frames, and has a communications unit which is allocated a respective slot in a traffic frame, and is allocated a slot in a signalling frame independent of the respective slot allocated in the traffic frame.
Preferably the time division multiplexed communications system further comprises a system controller where the functional operation of the signalling frame is controlled by the system controller and is dependent upon the level of communication activity measured on the signalling frame.
In this manner, the allocation of signalling resource in the time division multiplexed communications system is controlled according to the needs of communications units and the level of communication activity on the signalling frame.
Preferably the signalling frame of the time division multiplexed communications system is arranged for operation in at least two modes. In a first mode of operation the slots of the signalling frame are assigned to those communications units to which corresponding slots of traffic frames are assigned. In a second mode of operation the slots of the signalling frame are assigned to those communications units independent of the corresponding slots of assigned traffic frames. One slot of the signalling frame is reserved for broadcast message services and at least one bit of the broadcast message slot signifies the operational mode of the signalling frame.
In this manner, the operation of the signalling frame can be alternated at least between a normal signalling mode and a trunked signalling mode where the signalling resource is signalling message priority or on demand.
Advantageously, the communications units are informed of the functional operation of the signalling frame by an at least one-bit transmission on a broadcast message slot.
In a second aspect of the present invention, a method of operation of a time division multiplexed communications system is provided. The time division multiplexed communications system having a first communications unit communicating frame divided traffic and signalling information with a plurality of second communications unit. The method comprises the steps of allocating a respective slot in a traffic frame for transmissions from the first communications unit to a second communications unit. A slot in a signalling frame is allocated for signalling transmissions independent of the respective slot allocated in the traffic frame for transmissions from the first communications unit to a second communications unit.
In this manner, the signalling resource is allocated according to the signalling needs of the communications system and not to be consistent with the allocation of the traffic resource.
Preferably the signalling frame of the communications system is divided into slots and the functional operation of the signalling frame has at least two modes: a first mode of operation where the slots of the signalling frame are assigned to those second communications units to which corresponding slots of traffic frames are assigned, and in a second mode of operation the slots of the signalling frame are assigned to those second communications units independent of the corresponding slots of assigned traffic frames. The method further includes the steps of the first communications unit monitoring activity on the signalling frame of the time division multiplexed communications system and comparing the amount of activity on the signalling frame with the capacity of the signalling frame.
The first communications unit adapts the functional operation of the signalling frame to operate in the second mode of operation when the communications activity exceeds the capacity of the signalling frame.
Preferably the first communications unit transmits independent signalling messages in subsequent slots of the signalling frame when the communications activity exceeds the capacity of a single slot in the signalling frame. The first communications unit transmits a first signal on a respective signalling slot, i.e. a broadcast message slot, to each of the second communications units indicating the functional operation of the signalling frame. Second communications units scan a number of slots in the signalling frame to receive signalling information relevant to that particular second communications unit.
In this manner, the functional operation of the signalling resource is optimised according to the signalling needs of the time division communications system. Advantageously, when the signalling requirements exceed the signalling capacity of the communications system, trunking of the signalling channel is used.
A preferred embodiment of the invention will now be described, by way of example only, with reference to the drawings.
Brief Description of the Drawings FIG. 1 illustrates a general time division multiplexed communications system.
FIG. 2 is a diagram showing a prior art process of transmitting signalling messages.
FIG. 3 is a diagram showing a signalling frame structure, according to a preferred embodiment of the invention.
FIG. 4 is a flowchart showing options of signalling transmissions in the communications system in accordance with the preferred embodiment of the invention.
FIG. 5 is a flowchart showing the signalling operation of the communications system in accordance with the preferred embodiment of the invention.
FIG. 6 is a flowchart showing a preferred feature of the signalling operation of the communications system in accordance with the preferred embodiment of the invention.
FIG. 7 is a diagram showing a signalling frame structure in accordance with a preferred embodiment of the invention.
Detailed Description of the Drawings Referring first to FIG. 1, a general time division multiplexed communications system, is shown. The communications system comprises a first communications unit 13 communicating frame divided communications 10 with second communications units 15 and 17. The first communications unit has a system controller 11 and one second communications unit 15 has a scanning element 19. The frame divided communications 10 comprises a number of multi-frames 14 divided into eighteen time frames 12, seventeen of which are reserved for traffic communications and the eighteenth frame is reserved for signalling communications. Each traffic and signalling time frame is divided into four time slots 16, with the signalling frame being used for associated signalling for mobiles involved in calls.The associated signalling may be either call related, i.e. specific to a call, or call unrelated (not specific to a call but broadcast to all mobiles involved in calls). An example of a call related message is a short data message directed to one or more mobiles known to be involved in a call. An example of a call unrelated message is notification of an active group call on another traffic channel.
In operation a second communications unit 15 is allocated a respective time slot 16 in a traffic frame, and allocated signalling slots 20, 21, 22 and/or 23, in the signalling frame independent of the respective slot allocated in the traffic frame. Advantageously, the signalling frame resource is allocated according to the needs of the communications units communicating on the time division multiplexed communications system.
Referring now to FIG. 2, a diagram of a prior art process of transmitting signalling messages, is shown. The diagram shows a four slot signalling frame, for each of the first four multi-frames. Call related signalling messages are stored in call related signalling queues (CRSQs) 35 to 38 and transmitted in the signalling frame in the appropriate signalling slots, e.g. call related signalling messages from CSRQ 35 are transmitted to the communications unit allocated the first slot 21 in the signalling frame.
When no signalling messages are held within the CRSQ 35, 36, 37 and/or 38, call unrelated signalling messages are transmitted as shown, from the call unrelated signalling queue (CURSQ) 30.
In operation, a second communications unit, e.g. a mobile, transmits and receives speech on its allocated slot in frames one to seventeen of the traffic time frames. In addition, the mobile monitors its allocated slot for associated signalling in the eighteenth frame. Hence, all call unrelated messages need to be transmitted in every slot in the signalling frame to ensure that all mobiles involved in calls receive the message. In this manner, all subscriber units listen to their particular slots in order to receive each message, i.e. a subscriber unit allocated to slot one receives signalling message 'A' in multi-frame one, signalling message 'B' in multi-frame two and so on.This approach to associated signalling is wasteful of the bandwidth available as the same information is transmitted in every slot of the frame and increases the time delay for mobiles receiving the call unrelated messages.
Referring now to FIG. 3, a diagram of a signalling frame structure, according to a preferred embodiment of the invention, is shown. Signalling messages on the signalling frame involve either call related messages from a queue of call related messages 42 to 45 or call unrelated messages from a queue of call unrelated messages 40. The signalling frame occurs on the eighteenth frame of the first multi-frame 41 and on every eighteenth frame of each multi-frame thereafter. The first multi-frame 41 comprises four time slots 20, 21, 22 and 23.
In operation, mobiles involved in calls on the traffic channel are informed via a flag (at least one bit and preferably two bits) on the broadcast control channel (BCCH), either the BNCH or the BSCH, that they should listen to all four slots of the signalling frame. This configures the eighteenth frame as a trunked slow associated control channel (TSACCH). Call unrelated messages are now considered to be broadcast to all radios involved in calls on that carrier frequency, once the message has been transmitted on any of the four slots of the signalling frame. All call unrelated messages to be transmitted on the signalling frame are placed in the call unrelated signalling queue (CURSQ) 40. Call related signalling messages are placed in the call related signalling queues (CRSQ) 42 to 45 for the allocated slot for that call.When there are no pending call related signalling messages at the head of the CRSQ 42 on a specific slot within the signalling frame, i.e. the first time slot 20 of the first multi-frame 41, the message 'A' at the head of the CURSQ 40 is transmitted and the transmitted signalling message 'A' is sent to the back of the CURSQ 40. At the next slot 21 within the signalling frame, where there are no signalling messages in the CRSQ 43 of that slot 21, the same procedure is followed, i.e. the signalling message 'B' at the head of the CURSQ 40 is transmitted and the transmitted signalling message 'B' is sent to the back of the CURSQ 40. Consequently, call unrelated signalling messages are cycled faster. Advantageously, different information is transmitted in every slot making more efficient use of the information bandwidth and hence, the time to receive call unrelated message is reduced.
In a preferred embodiment of the present invention the time division multiplexed communications system includes a system controller 11 to control the functional operation of the signalling frame dependent upon the level of communication activity measured on the signalling frame. The signalling frame is arranged for operation in at least two modes. In a first (standard) mode of operation the slots of the signalling frame are assigned to those communications units to which corresponding slots of traffic frames are assigned, as described with regard to FIG. 2. In a second (TSACCH) mode of operation the slots of the signalling frame are assigned to those communications units independent of the corresponding slots of assigned traffic frames, as described with regard to FIG. 3.In the preferred embodiment, at least one slot or sub-slot of the signalling frame is reserved for broadcast message services and at least one bit of the broadcast message slot signifies the operational mode of the signalling frame.
Referring now to FIG. 4, a flowchart shows the method of allocating independent signalling frames and the decision process in choosing a signalling option in the communications system in accordance with the preferred embodiment of the invention. The method shows the signalling options of a time division multiplexed communications system having a first communications unit communicating frame divided traffic and signalling information with a plurality of second communications units. The method includes the steps of allocating a respective slot in a traffic frame, as in step 101, for transmissions from the first communications unit to a second communications unit.Advantageously, a slot is allocated in a signalling frame independent of the respective slot allocated in the traffic frame, as shown in step 102, for signalling transmissions from the first communications unit to the second communications unit. Such a method effectively trunks the operation of the signalling frame, i.e. the signalling frame enters a trunked SACCH mode.
The process of FIG. 4 starts, in step 100, with the allocation to a communications unit of a respective slot in the traffic frame, as in step 101.
At least one slot is allocated to the communications unit in the signalling frame, independent of the respective slot allocated in the traffic frame, as shown in step 102. The amount of communications activity on any signalling slot within the signalling frame is monitored and compared to the slot capacity, as in step 103. If the amount of signalling messages to be transmitted exceeds the capacity of the particular slot, as in step 103, a trunked slow associated control channel (TSACCH) mode of operation is employed, as shown in step 106. If the amount of signalling messages to be transmitted does not exceed the capacity of the particular slot in step 103, a normal slow associated control channel (SACCH) mode of operation is employed, as shown in step 104.Whichever mode of operation of the signalling frame is allocated, the mobile communications units are informed by the transmission of a first signal, as shown in step 107, before the allocation and decision process is complete, as in step 108.
Advantageously, the TSACCH mode of operation is only employed when the signalling capacity of any particular slot of the signalling frame in the communications system is exceeded.
The method described in FIG. 4 applies to a signalling frame of a communications system which is divided into slots and where the functional operation of the signalling frame has at least two modes. In a first mode of operation the slots of the signalling frame are assigned to those second communications units to which corresponding slots of traffic frames are assigned. In a second mode of operation the slots of the signalling frame are assigned to those second communications units independent of the corresponding slots of assigned traffic frames. The method includes the first communications unit monitoring activity on the signalling frame of the time division multiplexed communications system and comparing the amount of activity on the signalling frame with the capacity of the signalling frame.
The functional operation of the signalling frame is then operated in its second mode of operation when the communications activity exceeds the capacity of a slot within the signalling frame. The first communications unit transmits independent signalling messages in subsequent slots of the signalling frame and transmits a first signal on a respective signalling slot to each of the second communications units. The first signal indicates the functional operation of the signalling frame and the respective signalling slot is a broadcast message slot.
Advantageously, a second communications unit, capable of scanning a number of slots in the signalling frame, receives relevant signalling information faster than those second communications units unable to scan the whole of the signalling frame.
Referring now to FIG. 5, a flowchart of the timing of communications within the communications system, in accordance with a preferred embodiment of the invention, is shown. The process starts in step 120 and the status of the call related signalling queue (CRSQ) monitored, as in step 122. If a message exists in the CRSQ of step 122, the call related message is transmitted, as shown in step 124. If there is any more capacity in the slot, as in step 133, e.g. if a sub-slot structure is used, the process returns to step 122. If there is no more capacity for that particular slot the process stops, as shown in step 134. If a message does not exist in the CRSQ of step 120, the status of the call unrelated signalling queue (CURSQ) is monitored, as in step 126.If a message exists in the CURSQ of step 126, the call unrelated message is transmitted, as shown in step 128, the call unrelated message is placed at the back of the CURSQ, as shown in step 130. If there is any more capacity in the slot, as in step 133, e.g. if a sub-slot structure is used, the process returns to step 122. If there is no more capacity for that particular slot the process stops, as shown in step 134. If a message does not exist in the CURSQ of step 126, no signalling message is transmitted for that particular slot, as shown in step 132.
Referring now to FIG. 6, a flowchart of a preferred feature of the signalling operation of the communications system in accordance with the preferred embodiment of the invention, is shown. The process starts in step 150 and the status of the call related signalling queue (CRSQ) monitored, as in step 152. If a message exists in the CRSQ of step 152, the call related message is transmitted, as shown in step 154, and the process checks whether the slot is the last in the frame, as shown in step 162. If a message does not exist in the CRSQ of step 150, the status of the call unrelated signalling queue (CURSQ) is monitored, as in step 156. If a message exists in the CURSQ of step 156, an algorithm is used to point to the next signalling message for transmission from the CURSQ, as shown in step 158. The algorithm is defined as: 1+(SLOT-1) modulus (length of queue).
The algorithm rotates the signalling messages for transmission, as shown in more detail in FIG. 7. The term "SLOT" defines the current slot number for which the transmission is being prepared. The process then checks whether the slot is the last in the frame, as shown in step 162. If a message does not exist in the CURSQ of step 156, no signalling message is transmitted for that particular slot, as shown in step 160 and the process also moves to step 162. If the particular slot is the last one in the signalling frame, as in step 162, the head of the CURSQ is placed at the back of the queue, as shown in step 164, and the process stops, as in step 166, until the next signalling frame occurs. If the particular slot is not the last one in the signalling frame, as in step 162, the process stops for that particular slot, as shown in step 166.
Advantageously, the method of FIG. 6 supports mobiles which are not capable of scanning the whole of the signalling frame. All channels will eventually see all of the call unrelated messages, but there is a distinct advantage for mobiles scanning the whole of the signalling frame in that they will see all messages earlier. This process is further demonstrated in FIG. 7.
FIG. 7 is a diagram showing a signalling frame structure in accordance with a preferred embodiment of the invention, as detailed in FIG. 6. This method is particularly applicable when call unrelated signalling messages exceed the signalling capacity. Signalling messages on the signalling frame involve either call related messages from a queue of call related messages 62 to 65 or call unrelated messages from a queue of call unrelated messages 60.
The signalling frame occurs on the eighteenth frame of the first multi-frame 14 and on every eighteenth frame of each multi-frame thereafter. The multiframe 41 comprises four signalling time slots 20, 21, 22 and 23.
In operation, mobiles involved in calls on the traffic channel are informed via a flag on the BCCH (either the BNCH or the BSCH) that they should listen to all of the signalling frame. This configures the eighteenth frame as a trunked slow associated control channel (TSACCH). Call unrelated messages are now considered to be broadcast to all radios involved in calls on that carrier frequency. All call unrelated messages to be transmitted on the signalling frame are placed in the call unrelated signalling queue (CURSQ) 60. Call related signalling messages are placed in the call related signalling queues (CRSQ) 62 to 65 for the particular slot for that call.When there are no pending call related signalling messages at the head of the CRSQ on a specific slot within the signalling frame, i.e. the first time slot 20 of the eighteenth frame of the first multi-frame 41 with associated CRSQ 62, the signalling message 'A' at the head of the CURSQ 60 is transmitted. At the next slot 21 within the signalling frame, where there are no signalling messages in the CRSQ 63 of that slot 21, the next message in the CURSQ 60 is transmitted, i.e. the signalling message 'B' at the head of the CURSQ 60 is transmitted. This process continues until the last signalling slot has been used, at which point the head of the CURSQ 60, i.e.
signalling message 'A' in FIG. 7, is placed at the back of the CURSQ 60.
Consequently, all channels will eventually see all of the call unrelated messages, but there is a distinct advantage for mobiles scanning all of the signalling frame, in that they will receive all signalling messages earlier than mobiles who can not scan all of the signalling frame.
In a preferred feature of the present invention call related signals from the CRSQ of another slot are transmitted. The decision on whether to transmit call related signals of another slot is dependent on the priority basis or on a queue loading basis, i.e. monitoring the status of the queues. A further enhancement is gained by placing all of the signalling messages in a single prioritised queue and scheduling them for transmissions accordingly.
Such enhancements rely on all mobiles being able to scan all of the signalling frame.
It is within the contemplation of the invention that the signalling format, described above with regard to downlink communications between the system and mobile communications units, is equally applicable for uplink communications from mobile communications units to the system. Time frames, slots and sub-slots are described in a relative manner.
The preferred embodiment of the invention has been described with regard to a single-site communications system. It is considered that the all of the aspects to the preferred embodiment are equally applicable in a multisite communications system, wberein a higher level of signalling control is used. In such a multi-site system, the allocation of signalling resource throughout the communications sites, is primarily dependent upon the priority of the signalling messages to be transmitted throughout the multisite system or within the individual single-site communications systems.
A TDM communications system has thus been described which provides frame divided communications and in which a given slot of each traffic frame is allocated to a given channel or subscriber unit and in which a signalling frame is provided. The signalling frame is divided into slots and the slots of the signalling frame are selectively used by channels or subscriber units other than the channels or subscriber units to which corresponding traffic slots are allocated. The slots of the signalling frame selected for use are either allocated by the system controller or selected by the subscriber unit.
Thus, an improved method for transmission of signalling information whilst communications units are involved in a call is provided. A timing structure for a time division multiplexed communications system offering enhanced traffic and signalling communications is also given.

Claims (11)

Claims
1. A time division multiplexed communications system comprising time frames divided into traffic frames and signalling frames, wherein a communications unit is allocated a respective slot in a traffic frame, and is allocated a slot in a signalling frame independent of the respective slot allocated in the traffic frame.
2. The time division multiplexed communications system of claim 1 further comprising a system controller wherein functional operation of a signalling frame is controlled by the system controller and is dependent upon the level of communication activity measured on the signalling frame.
3. The time division multiplexed communications system of claim 2 wherein a signalling frame is arranged for operation in at least two modes and wherein in a first mode of operation slots of the signalling frame are assigned to those communications units to which corresponding slots of traffic frames are assigned, and in a second mode of operation the slots of the signalling frame are assigned to those communications units independent of corresponding slots of assigned traffic frames.
4. The time division multiplexed communications system of claims 2 and 3 wherein one slot of a signalling frame is reserved for broadcast message services and wherein at least one bit of a broadcast message slot signifies an operational mode of the signalling frame.
5. The time division multiplexed communications system of any of the preceding claims wherein the communications system is a Trans European Trunked Radio system, a signalling frame is an eighteenth frame of the Trans European Trunked Radio timing format and broadcast messages are transmitted on a broadcast service channel (BSCH) and a broadcast network channel (BNCH).
6. A method of operation of a time division multiplexed communications system having a first communications unit communicating frame divided traffic and signalling information with a plurality of second communications unit, the method comprising the steps of: allocating a respective slot in a traffic frame for transmissions from the first communications unit to a second communications unit, and allocating a slot in a signalling frame independent of the respective slot allocated in the traffic frame for transmissions from the first communications unit to a second communications unit.
7. The method according to claim 6 wherein a signalling frame of a communications system is divided into slots and functional operation of the signalling frame has at least two modes, wherein in a first mode of operation slots of the signalling frame are assigned to those second communications units to which corresponding slots of traffic frames are assigned, and in a second mode of operation slots of the signalling frame are assigned to those second communications units independent of corresponding slots of assigned traffic frames, the method further comprising the steps of:: monitoring signalling activity on the time division multiplexed communications system, by a first communications unit, comparing a level of signalling activity with a signalling slot capacity, and adapting signalling format to the second mode of operation when signalling activity exceeds the signalling slot capacity.
8. The method according to claim 6 and 7, further including the step of transmitting independent signalling messages in subsequent slots of a signalling frame by a first communications unit.
9. The method according to claims 6 to 8, further comprising the step of transmitting a first signal on a respective signalling slot from a first communications unit to each second communications unit wherein the first signal is indicative of a signalling mode of operation and the respective signalling slot is a broadcast message slot.
10. The method according to claims 6 to 9, further comprising the step of a second communications unit scanning a number of slots in a signalling frame in order to receive signalling information relevant to the second communications unit.
11. The method according to claims 6 to 10 wherein a single queue of signalling messages is transmitted on the downlink trunked slow associated control channel of the communications system according to the individual priority of signalling messages.
GB9511131A 1995-06-01 1995-06-01 Communications system and method of operation Expired - Fee Related GB2301749B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9511131A GB2301749B (en) 1995-06-01 1995-06-01 Communications system and method of operation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9511131A GB2301749B (en) 1995-06-01 1995-06-01 Communications system and method of operation

Publications (3)

Publication Number Publication Date
GB9511131D0 GB9511131D0 (en) 1995-07-26
GB2301749A true GB2301749A (en) 1996-12-11
GB2301749B GB2301749B (en) 1999-07-28

Family

ID=10775372

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9511131A Expired - Fee Related GB2301749B (en) 1995-06-01 1995-06-01 Communications system and method of operation

Country Status (1)

Country Link
GB (1) GB2301749B (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998036533A1 (en) * 1997-02-17 1998-08-20 Communication & Control Electronics Limited Local communication system
GB2322525A (en) * 1997-02-21 1998-08-26 Motorola Ltd A method of allocating a TDM communication resource
WO2000008885A1 (en) * 1998-08-03 2000-02-17 Nokia Networks Oy Method for improving the performance of ussd transfer in a cellular communications system
WO2000022852A1 (en) * 1998-10-13 2000-04-20 Nokia Networks Oy Speech/ussd interoperability mechanism
WO2000060813A1 (en) * 1999-04-02 2000-10-12 Qualcomm Incorporated System and method for prioritizing traffic channel messages
DE19823815C2 (en) * 1998-05-27 2003-03-27 Nokia Deutschland Gmbh Access node with a data connection for operational and maintenance functions (OA&M)
WO2003067915A1 (en) * 2002-02-08 2003-08-14 Koninklijke Philips Electronics N.V. Radio communication system
US6781971B1 (en) 1999-04-02 2004-08-24 Qualcomm Incorporated System and method for prioritizing traffic channel messages
EP1734776A1 (en) * 2005-06-16 2006-12-20 Siemens Aktiengesellschaft Method for SACCH signaling

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4178479A (en) * 1978-02-06 1979-12-11 Trw, Inc. Communication processor apparatus for use in a TDM switching system
US5199031A (en) * 1990-08-31 1993-03-30 Telefonaktiebolaget L M Ericsson Method and system for uniquely identifying control channel time slots

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4178479A (en) * 1978-02-06 1979-12-11 Trw, Inc. Communication processor apparatus for use in a TDM switching system
US5199031A (en) * 1990-08-31 1993-03-30 Telefonaktiebolaget L M Ericsson Method and system for uniquely identifying control channel time slots

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998036533A1 (en) * 1997-02-17 1998-08-20 Communication & Control Electronics Limited Local communication system
US6865188B1 (en) 1997-02-17 2005-03-08 Communication & Control Electronics Limited Local communication system
GB2322525A (en) * 1997-02-21 1998-08-26 Motorola Ltd A method of allocating a TDM communication resource
GB2322525B (en) * 1997-02-21 2001-12-12 Motorola Ltd A method of allocating a TDM communication resource
DE19823815C2 (en) * 1998-05-27 2003-03-27 Nokia Deutschland Gmbh Access node with a data connection for operational and maintenance functions (OA&M)
US6834196B1 (en) 1998-08-03 2004-12-21 Nokia Networks Oy Method for improving the performance of USSD transfer in a cellular communications system
WO2000008885A1 (en) * 1998-08-03 2000-02-17 Nokia Networks Oy Method for improving the performance of ussd transfer in a cellular communications system
WO2000022852A1 (en) * 1998-10-13 2000-04-20 Nokia Networks Oy Speech/ussd interoperability mechanism
US6721575B1 (en) 1998-10-13 2004-04-13 Nokia Networks Oy Speech/USSD interoperability mechanism
US6781971B1 (en) 1999-04-02 2004-08-24 Qualcomm Incorporated System and method for prioritizing traffic channel messages
WO2000060813A1 (en) * 1999-04-02 2000-10-12 Qualcomm Incorporated System and method for prioritizing traffic channel messages
WO2003067915A1 (en) * 2002-02-08 2003-08-14 Koninklijke Philips Electronics N.V. Radio communication system
US7554943B2 (en) 2002-02-08 2009-06-30 Koninklijke Philips Electronics N.V. Radio communication system
US8199711B2 (en) 2002-02-08 2012-06-12 Koninklijke Philips Electronics N.V. Radio communication system
EP1734776A1 (en) * 2005-06-16 2006-12-20 Siemens Aktiengesellschaft Method for SACCH signaling

Also Published As

Publication number Publication date
GB2301749B (en) 1999-07-28
GB9511131D0 (en) 1995-07-26

Similar Documents

Publication Publication Date Title
JP4298161B2 (en) Variable block scheduling method of indication by uplink state flag in packet data communication system
CA2135950C (en) Method of multiple access
US6026083A (en) Transmission of control messages in digital telephony
JP3450196B2 (en) TDMA wireless communication system
JP4128329B2 (en) Transmission of information in telecommunications systems
EP0687078B1 (en) A system for transmitting packet data in radio telephone TDMA systems
US5465253A (en) Method and apparatus for demand-assigned reduced-rate out-of-band signaling channel
US6134231A (en) Uplink channel puncturing for reduced interference within a wireless data communications network
US20050117536A1 (en) System and method for transmitting and receiving resource allocation information in a wireless communication system
US6469996B1 (en) Method of allocating transmission channels to a mobile station, in particular in duplex mode, in a mobile packet-mode telecommunications network
RU2216100C2 (en) Method for planning readings of variable blocks with aid of status flag of ascending communication line in burst data transmission system
US6442156B1 (en) Method and device in a mobile telecommunication network
US20030117990A1 (en) Method and base station system for calling mobile stations for the transmission of packet data
EP0644702A1 (en) Communication protocol for a mobile communication system
GB2301749A (en) Allocation of signalling and traffic slots in TDM communication system
EP0781497B1 (en) Method for restricting channel access depending on subscriber classes and system loading
KR101502922B1 (en) Allocating traffic channels in a communications system
US6038213A (en) Method for restricting channel access depending on subscriber classes and system loading
AU732544B2 (en) Method of implementing a handover in a cellular radio system
AU9414998A (en) Method of allocating transmission channels to mobile station in packet-s witched mode
EP1063860B1 (en) Method and system for multiple acess in a radiocommunication system
GB2357399A (en) Control channnel utilisation within a cellular communication system
EP0860061B1 (en) Digital telephony using control messages transmitted in time slots for rf frequency allocation

Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20140601