CA1339157C - Connection of subscriber communication network base station to external information network - Google Patents
Connection of subscriber communication network base station to external information networkInfo
- Publication number
- CA1339157C CA1339157C CA000615508A CA615508A CA1339157C CA 1339157 C CA1339157 C CA 1339157C CA 000615508 A CA000615508 A CA 000615508A CA 615508 A CA615508 A CA 615508A CA 1339157 C CA1339157 C CA 1339157C
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- Prior art keywords
- communication
- channel
- time slots
- predetermined
- given
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- Expired - Lifetime
Links
- 238000004891 communication Methods 0.000 title claims abstract description 83
- 230000003252 repetitive effect Effects 0.000 claims abstract description 22
- 230000008878 coupling Effects 0.000 claims 1
- 238000010168 coupling process Methods 0.000 claims 1
- 238000005859 coupling reaction Methods 0.000 claims 1
- 238000002592 echocardiography Methods 0.000 claims 1
- 238000000926 separation method Methods 0.000 claims 1
- 230000008859 change Effects 0.000 description 12
- 230000011664 signaling Effects 0.000 description 9
- 230000009471 action Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 4
- 230000007704 transition Effects 0.000 description 3
- 230000003750 conditioning effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/08—Access point devices
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W28/00—Network traffic management; Network resource management
- H04W28/02—Traffic management, e.g. flow control or congestion control
- H04W28/10—Flow control between communication endpoints
- H04W28/14—Flow control between communication endpoints using intermediate storage
-
- 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
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access
- H04W74/04—Scheduled access
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W92/00—Interfaces specially adapted for wireless communication networks
- H04W92/02—Inter-networking arrangements
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- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
A base station in a subscriber communication network for communicating signals between subscriber stations and an external communication network having a plurality of ports. The base station includes a communication circuit for enabling simultaneous communications between a plurality of the ports and a plurality of subscriber stations over a given communication channel having multiple sequentially repetitive time slots, with predetermined time slots being assigned respectively to predetermined subscribers stations; a remote-connection processor for directing communications between the time slot assigned to a given subscriber station and a given external communication network port; and an exchange for connecting the communication circuit to the external communication network ports. The exchange includes a central concentrator for directing signals from predetermined external network ports to predetermined sequentially repetitive time slots in a bit stream generated by the central concentrator, and for directing signals to predetermined external network ports from predetermined sequentially repetitive time slots in a bit stream received by the central concentrator; and the remote-connection processor directs signal transfer between given sequentially repetitive time slots of the bit streams and given sequentially repetitive time slots of the communication channel. The remote-connection processor includes a remote concentrator for directing signals from predetermined remote ports to predetermined sequentially repetitive time slots in a bit stream generated by the remote concentrator and transmitted to the central concentrator, and for directing signals to predetermined remote ports from predetermined sequentially repetitive time slots in the bit stream generated by the central concentrator; and a buffer unit connected to the remote ports for directing signals between predetermined remote ports and predetermined communication channel time slots. The exchange may be located remotely from the communication circuit; and the bitstream may be transmitted between the exchange and the communication circuit by microwave.
Description
CONNECTION OF SUBSCRIBER COMMUNICATION NETWORK
BASE STATION TO EXTERNAL INFORMATION NETWORK
BACKGROUND OF THE INVENTION
The present invention generally pertains to communications systems and is particularly directed to an improvement in connecting a subscriber communication network base station to an external communication network having a plurality of ports.
A known prior art base station in a subscriber communication network for communicating signals between subscriber stations and an lo external co~munication network having a plurality of ports, includes a communication circuit for enabling simultaneous communications between a plurality of the ports and a plurality of subscriber stations over a given communication channel having multiple sequentially repetitive time slots, with predeternined time slots being assigned respectively to predetermined subscriber stations; a remote-connection processor for directing communications between the time slot assigned to a given subscriber station and a given port; and an exchange for connecting the communication circuit to the ports. The exchange includes a switch *
which responds to a control signal from the remote-connection processor by physically connecting a selected port to a selected communication channel time slot assigned to a given subscriber station. Such a prior art base station is described in United States Patent No. 4,675,863, E. Paneth et al, issued on June 23, 1987.
SUMMARY OF THE INVENTION
The present invention provides an improved base station of the type generally described above, except that the exchange does not include such a switch. The base station of the present invention is characterized by the exchange including a central concentrator for directing signals from predetermined external network ports to predetermined sequentially repetitive time slots in a bit stream generated by the central concentrator, and for directing signals to predetermined external network ports from predetermined sequentially repetitive time slots in a bit stream received by the central concentrator; and by the remote-connection processor directing signal transfer between given sequentially repetitive time slots of the bit streams and given sequentially repetitive time slots of the communication channel.
~ 3391~7 The base station of the present invention is further characterized by the remote-connection processor comprising a remote terminal concentrator for directing signals from predetermined remote ports to predetermined sequentially repetitive time slots in a bit stream generated by the remote concentrator and transmitted to the central concentrator, and for directing signals to predetermined remote ports from predetermined sequentially repetitive time slots in the bit stream generated~ by the central concentrator; and a buffer unit connected to the remote ports for directing signals between predetermined remote ports and predetermined communication channel time slots.
Because the exchange of the base station of the present invention co~m~lnicates with the cammunication circuit by generating and receiving bitstreams as described above, it is practical to locate the lS exchange of the base station of the present invention remotely from the communication circuit of the base station since the bitstream may be transmitted between the exchange and the communication circuit over appreciable distances by microwave.
Additional features of the present invention are described with reference to the description of the preferred embodiment.
13391~7 BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a block diagram of a preferred embodiment of the base station of the present invention.
Figure 2 is a block diagram of a buffer unit included in the S buffer of the base station of Figure 1 for interfacing with a single channel module.
Figure 3 is a state diagram illustrating normal call processing flow in the base station of Figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the base station of the present invention is used in a subscriber telephone system.
Referring to Figure 1, a preferred embodiment of the base station of the present invention includes an exchange 10, a communication circuit 12 and a remote-connection processor 14. The communication circuit 12 and the remote control processor 14 are located remotely from the exchange 10.
The exchange lO includes a two-to-four wire converter 16, a signalling data converter 17, an echo canceller 18, and a central 5concentrator 19. The communication circuit 12 includes a plurality of channel modules 21a, ..., 21n. Each channel module 21 includes a voice codec unit (VCU) 23, a channel control unit (CCU) 24 and a modem 25.
The remote-connection processor 14 includes a remote concentrator 27 and a buffer unit 28.
loReferring to Figure 2, the buffer unit 28 includes a timing generator 30 and a channel interface module 32.
Referring again to Figure 1, the exchange 10 is connected to a plurality of ports of a central office 35 by N pairs of lines 37. "N"
is the number of subscriber stations being served by the base station.
15Each pair of lines 37 provides a 2-wire loop appearance. Each line pair 37 is connected to both the two-to-four wire converter 16, and the sign~lt~ng data converter 17. Unidirectional signal flow takes place on the line pairs 38-41 on the other sides of the converters 16, 17, with 4-wire loop appearances being provided on the combination of N line pairs 38 and N line pairs 39. Transmitted voice signals are provided on line pairs 38; recieved voice signals are provided on line pairs 39;
transmitted sign~ ng data is provided on line pairs 40; and received signalling data is provided on line pairs 41.
The transmitted and received voice signals are CQ' lln~cated between the two-to-four wire converter 16 and the central concentrator 19 through the echo canceller 18. The sign~lling data is communicated directely between the converter 17 and the central concentrator 19.
The central concentrator 19 is a Model 1218C concentrator sold by ITT Corp.
The central concentrator 19 directs signals from predetermined line pairs 38-41 (which are connected to predetermined external network ports in the central office 35) to predetermined sequentially repetitive time slots in a bit stream generated by the central concentrator 19.
The central concentrator 19 also directs signals to predetermined external network ports in the central office via predetermined line pairs 38-41 from predetermined sequentially repetitive time slots in a bit stream recieved by the central concentrator 19. The central concentrator transmits and receives such bit streams via a microwave antenna 43.
These bit streams are communicated between the antenna 43 and a microwave antenna 44 connected to the remote concentrator 27 contained in the remote-connection processor 14. The remote concentrator 27 has a plurality of remote ports connected to the buffer 28 by line pairs 46-49.
The remote concentrator 27 is a Model 1218S concentrator sold by rTT Corp.
The remote concentrator 27 directs signals from predetermined remote terminals (which are connected to predetermined line pairs 46-49) lo to predetermined sequentially repetitive time slots in a bit stream generated by the remote concentrator 27. The remote concentrator 27 also directs signals to predetermined remote ports from predetermined sequentially repetitive time slots in the bit stream recieved by the remote concentrator 27 from the central concentrator 19.
The transmitted voice signals are provided on line pairs 46; the recieved voice signals are provided on line pairs 47; the transmitted sign~lling data is provided on line pairs 48; and the recieved signalling data is provided on the line pairs 49.
The buffer 28 interfaces the remote concentrator 27 with the communication circuit 12.
As described above, the communication circuit 12 include,s a plurality of channel modules 21. Each channel module 21 commlnicates with a given number of subscriber stations 51 over a given communication channel having an assigned frequency and further having multiple sequentially repetitive time slots. Communication between each channel module 21 and the base stations 51 is via a microwave link between a base station antenna 53 and antennas 54 located at each subscriber station. Predetermined time slots are assigned to predetermined subscriber stations 51. In the preferred embodiment, there are three subscriber stations 51 coupled to each channel module 19 over each discrete frequency communication channel. Each subscriber station 51 has a telephone connected thereto.
In each ~h~nn~l module 21, the VCU 23 includes a separate voice codec (not shown~ for each subscriber station 51 and an additional codec for comm~lnicating signalling data to and from all three subscriber stations. The CCU 24 assigns the signals communicated through the codecs of the VCU 23 to different time slots of the communication r,h~nnPl assigned to the given channel module 21. These signals are communicated between the CCU 24 and the base station antenna 53 via the modem 25 and additional signal conditioning components (not shown) adapted for transmitting and recieving these signals over the discrete communication ch~nnel at the assigned frequency. Thus, each subscriber station ~1 communicates voice signals with the base station over its own predetermined time slot and communicates signalling data with the base station over a predetermined time slot that is common to all three subscriber stations. Com~nication between the base station and the subscriber stations is controlled by a radio control unit (RCU) software process implemented by a microcomputer in the CCU 24.
The RCU is programmed to recognize three predetermined subscriber stations corresponding to three predetermined line appearances provided by the connections between the remote concentrator 27 and a given channel module 21.
lS Control processing in the RCU is organized using state machines.
Input message tokens include sign~1ling data from the remote concentrator 27, radio control channel (RCC) messages from the subscriber stations, and (simulated) baseband control channel (BCC) messages.
The state diagram, Fig. 3, illustrates the normal call processing states and the input token (T) and the resulting action (A) required to transit from one state to another. The following descriptions outline some of the state transition routines. Other routines, such as those required for error handling, have not been described.
The following group of descriptions define some of the RCC state transition routines which are called whenever a RCC token is received by a CCU, whether from a subscriber station or the remote concentrator.
Clear Call (cl call) Current State: Active, Teardown Token: Clear Request Next State (RCC): RCC Idle ~-O
Next State (CHAN): Chnl Idle Messages:
Conc: Place circuit in idle state.
RCC: None.
CCU: Change channel (onhook) is sent to the CCU.
Actions:
This routine is invoked whenever a subscriber station generates a Clear Request. The channel state is set to Chnl Idle. The clear-request timer is cancelled. Whether or not teardown was in progress, the RCU considers the subscriber station available for another call, and returns the RCC state to RCC Idle.
Place Call Origination (place) Current State: RCC Idle Token: Call Request i339157 Next State (RCC): Active Next State (CHAN): Offhk Syn Wait Messages:
Conc: Place circuit in loop state.
RCC: Send Call Connect message to Subscriber Station.
CCU: Send Change Channel (OFFHOOK).
Actions:
This routine is invoked when a Subscriber Station is in the RCC
Idle state and the RCU receives a Call Request token. A Change Channel message with an Offhook status is sent to the CCU, and a Call Connect message is sent to the Subscriber Station. The channel state of the allocated frequency is set to Offhk Syn Wait, and the RCC state is set to Active.
- Subscriber Stati~n Call Accept (s accp) Current State: Page Token: Call Accept Next State (RCC): Active Next State (CHAN): Ring Syn Wait Messages:
Conc: Place circuit in loop state.
RCC: Send Call Connect message.
CCU: Send Change Channel (RING).
Actions:
This routine is invoked when the RCU receives a Call Accept token from a Subscriber Station that is in the Page state. The page timer is cancelled. A Change Channel message with Ring status is sent to the CCU, and a Call connect message is sent to the Subscriber Station. The channel state is set to Ring Syn Wait, and the RCC state is set to Active.
l339l57 Subscriber Station Page (s_page) Current State: RCC Idle l339l57 Token: Incoming Ring Next State (RCC): Page Next State (CHAN): No state change Messages:
Conc: None.
RCC: Send a Page message if the Subscriber Station.
CCU: None Actions:
If an Incoming Ring token is received from the concentrator while the Subscriber Station is in the RCC
Idle state, then this routine is invoked. The line appearance is mapped to a predetermined Page message, which is then transmitted to the appropriate Subscriber Station.
A timer is set in case the Subscriber Station does not respond to the page. The RCC state is set to Page.
The following group of descriptions define some of the channel state transition routines which are called whenever a token is received from a CCU.
1339ls7 Subscriber Station Ring Trip (rng_offhk) Current State: Syn Ring, Ring Syn Wait Token: Sync Offhook Next State (RCC): No state change Next State (CHAN): Syn Offhk Messages:
Conc: None.
RCC: None.
CCU: Send Change Channel (OFFHOOK) to the CCU.
Actions:
This routine is activated when a Subscriber Station is in the ring state and either in or out of synchronization, and the RCU receives 13~9157 a message that the Subscriber Station is now in synchronization and has transitioned to Offhook. Normally, when a Sync Offhook token is received, the Subscriber Station is already in synchronization. The CCU
is sent a Change Channel message with Offhook status, and the channel state is changed to Syn Offhk.
Subscriber Station Sync Offhook (syn offhk) Current State: Offhk Syn Wait Token: Sync Offhook Next State (RCC): No state change lo Next State (CHAN): Syn Offhk Messages:
Conc: None.
RCC: None.
CCU: None.
Actions:
This routine generates no messages, it only causes a change in channel state to Sync Offhk.
Subscriber Station Sync Ring (syn ring) Current State: Ring Syn Wait Token: Sync Ring 13391~7 Next State (RCC): No state change Next State (CHAN): Syn Ring Messages:
Conc: None.
RCC: None.
CCU: None.
Actions:
This routine changes the channel state to Syn Ring.
The buffer 28 is connected to the remote ports of the remote lo concentrator 27 via line pairs 46-49 and to the ~h~nnel modules 21 of the communication circuit 14 via lines 57 for directing the transmitted and recieved voice signals between the predetermined remote ports of the remote concentrator 27 and the predetermined communication channel time slots assigned to predetermined subscriber stations 51. The subscriber stations 51 are located remotely from the base station.
The buffer 28 includes a separate buffer unit, as shown in Figure 2, for interfacing with each channel module 21 in the communication circuit 12. The timing generator 30 provides the channel interface module 32 with a clock signal CLK and four gate signals Gate 0, Cate 1, Gate 2, Gate 3 for defining four sequentially repetitive time slots in the assigned communication ch~nnel.
The transmitted voice signal line pairs 46, the received voice signal line pairs 47, and the the signalling data line pairs 48, 49 are connected between the remote ports of the concentrator 27 and the channel interface module 32.
The channel interface module 32 provides the clock and gate signals to the channel module 27 for defining the time slots assigned by the CCU 24.
The channel interface module 32 is connected to the VCU 23 in the corresponding channel module 21 in a predetermined manner for directing communications between line pairs 46, 47 carrying transmitted and received voice signals associated with a given subscriber station and a codec in the VCU 23 having the predetermined communication channel time slot assigned by the CCU 24 to the given subscriber station. The channel interface module is further connected to the VCU 23 for directing the signalling data between the signalling data line pairs 48, 49 and the the voice codec in the VCU having the common time slot ~,o assigned by the CCU 24 for communicating signalling data ~or all three subscriber stations associated with the given channel module.
~l
BASE STATION TO EXTERNAL INFORMATION NETWORK
BACKGROUND OF THE INVENTION
The present invention generally pertains to communications systems and is particularly directed to an improvement in connecting a subscriber communication network base station to an external communication network having a plurality of ports.
A known prior art base station in a subscriber communication network for communicating signals between subscriber stations and an lo external co~munication network having a plurality of ports, includes a communication circuit for enabling simultaneous communications between a plurality of the ports and a plurality of subscriber stations over a given communication channel having multiple sequentially repetitive time slots, with predeternined time slots being assigned respectively to predetermined subscriber stations; a remote-connection processor for directing communications between the time slot assigned to a given subscriber station and a given port; and an exchange for connecting the communication circuit to the ports. The exchange includes a switch *
which responds to a control signal from the remote-connection processor by physically connecting a selected port to a selected communication channel time slot assigned to a given subscriber station. Such a prior art base station is described in United States Patent No. 4,675,863, E. Paneth et al, issued on June 23, 1987.
SUMMARY OF THE INVENTION
The present invention provides an improved base station of the type generally described above, except that the exchange does not include such a switch. The base station of the present invention is characterized by the exchange including a central concentrator for directing signals from predetermined external network ports to predetermined sequentially repetitive time slots in a bit stream generated by the central concentrator, and for directing signals to predetermined external network ports from predetermined sequentially repetitive time slots in a bit stream received by the central concentrator; and by the remote-connection processor directing signal transfer between given sequentially repetitive time slots of the bit streams and given sequentially repetitive time slots of the communication channel.
~ 3391~7 The base station of the present invention is further characterized by the remote-connection processor comprising a remote terminal concentrator for directing signals from predetermined remote ports to predetermined sequentially repetitive time slots in a bit stream generated by the remote concentrator and transmitted to the central concentrator, and for directing signals to predetermined remote ports from predetermined sequentially repetitive time slots in the bit stream generated~ by the central concentrator; and a buffer unit connected to the remote ports for directing signals between predetermined remote ports and predetermined communication channel time slots.
Because the exchange of the base station of the present invention co~m~lnicates with the cammunication circuit by generating and receiving bitstreams as described above, it is practical to locate the lS exchange of the base station of the present invention remotely from the communication circuit of the base station since the bitstream may be transmitted between the exchange and the communication circuit over appreciable distances by microwave.
Additional features of the present invention are described with reference to the description of the preferred embodiment.
13391~7 BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a block diagram of a preferred embodiment of the base station of the present invention.
Figure 2 is a block diagram of a buffer unit included in the S buffer of the base station of Figure 1 for interfacing with a single channel module.
Figure 3 is a state diagram illustrating normal call processing flow in the base station of Figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the base station of the present invention is used in a subscriber telephone system.
Referring to Figure 1, a preferred embodiment of the base station of the present invention includes an exchange 10, a communication circuit 12 and a remote-connection processor 14. The communication circuit 12 and the remote control processor 14 are located remotely from the exchange 10.
The exchange lO includes a two-to-four wire converter 16, a signalling data converter 17, an echo canceller 18, and a central 5concentrator 19. The communication circuit 12 includes a plurality of channel modules 21a, ..., 21n. Each channel module 21 includes a voice codec unit (VCU) 23, a channel control unit (CCU) 24 and a modem 25.
The remote-connection processor 14 includes a remote concentrator 27 and a buffer unit 28.
loReferring to Figure 2, the buffer unit 28 includes a timing generator 30 and a channel interface module 32.
Referring again to Figure 1, the exchange 10 is connected to a plurality of ports of a central office 35 by N pairs of lines 37. "N"
is the number of subscriber stations being served by the base station.
15Each pair of lines 37 provides a 2-wire loop appearance. Each line pair 37 is connected to both the two-to-four wire converter 16, and the sign~lt~ng data converter 17. Unidirectional signal flow takes place on the line pairs 38-41 on the other sides of the converters 16, 17, with 4-wire loop appearances being provided on the combination of N line pairs 38 and N line pairs 39. Transmitted voice signals are provided on line pairs 38; recieved voice signals are provided on line pairs 39;
transmitted sign~ ng data is provided on line pairs 40; and received signalling data is provided on line pairs 41.
The transmitted and received voice signals are CQ' lln~cated between the two-to-four wire converter 16 and the central concentrator 19 through the echo canceller 18. The sign~lling data is communicated directely between the converter 17 and the central concentrator 19.
The central concentrator 19 is a Model 1218C concentrator sold by ITT Corp.
The central concentrator 19 directs signals from predetermined line pairs 38-41 (which are connected to predetermined external network ports in the central office 35) to predetermined sequentially repetitive time slots in a bit stream generated by the central concentrator 19.
The central concentrator 19 also directs signals to predetermined external network ports in the central office via predetermined line pairs 38-41 from predetermined sequentially repetitive time slots in a bit stream recieved by the central concentrator 19. The central concentrator transmits and receives such bit streams via a microwave antenna 43.
These bit streams are communicated between the antenna 43 and a microwave antenna 44 connected to the remote concentrator 27 contained in the remote-connection processor 14. The remote concentrator 27 has a plurality of remote ports connected to the buffer 28 by line pairs 46-49.
The remote concentrator 27 is a Model 1218S concentrator sold by rTT Corp.
The remote concentrator 27 directs signals from predetermined remote terminals (which are connected to predetermined line pairs 46-49) lo to predetermined sequentially repetitive time slots in a bit stream generated by the remote concentrator 27. The remote concentrator 27 also directs signals to predetermined remote ports from predetermined sequentially repetitive time slots in the bit stream recieved by the remote concentrator 27 from the central concentrator 19.
The transmitted voice signals are provided on line pairs 46; the recieved voice signals are provided on line pairs 47; the transmitted sign~lling data is provided on line pairs 48; and the recieved signalling data is provided on the line pairs 49.
The buffer 28 interfaces the remote concentrator 27 with the communication circuit 12.
As described above, the communication circuit 12 include,s a plurality of channel modules 21. Each channel module 21 commlnicates with a given number of subscriber stations 51 over a given communication channel having an assigned frequency and further having multiple sequentially repetitive time slots. Communication between each channel module 21 and the base stations 51 is via a microwave link between a base station antenna 53 and antennas 54 located at each subscriber station. Predetermined time slots are assigned to predetermined subscriber stations 51. In the preferred embodiment, there are three subscriber stations 51 coupled to each channel module 19 over each discrete frequency communication channel. Each subscriber station 51 has a telephone connected thereto.
In each ~h~nn~l module 21, the VCU 23 includes a separate voice codec (not shown~ for each subscriber station 51 and an additional codec for comm~lnicating signalling data to and from all three subscriber stations. The CCU 24 assigns the signals communicated through the codecs of the VCU 23 to different time slots of the communication r,h~nnPl assigned to the given channel module 21. These signals are communicated between the CCU 24 and the base station antenna 53 via the modem 25 and additional signal conditioning components (not shown) adapted for transmitting and recieving these signals over the discrete communication ch~nnel at the assigned frequency. Thus, each subscriber station ~1 communicates voice signals with the base station over its own predetermined time slot and communicates signalling data with the base station over a predetermined time slot that is common to all three subscriber stations. Com~nication between the base station and the subscriber stations is controlled by a radio control unit (RCU) software process implemented by a microcomputer in the CCU 24.
The RCU is programmed to recognize three predetermined subscriber stations corresponding to three predetermined line appearances provided by the connections between the remote concentrator 27 and a given channel module 21.
lS Control processing in the RCU is organized using state machines.
Input message tokens include sign~1ling data from the remote concentrator 27, radio control channel (RCC) messages from the subscriber stations, and (simulated) baseband control channel (BCC) messages.
The state diagram, Fig. 3, illustrates the normal call processing states and the input token (T) and the resulting action (A) required to transit from one state to another. The following descriptions outline some of the state transition routines. Other routines, such as those required for error handling, have not been described.
The following group of descriptions define some of the RCC state transition routines which are called whenever a RCC token is received by a CCU, whether from a subscriber station or the remote concentrator.
Clear Call (cl call) Current State: Active, Teardown Token: Clear Request Next State (RCC): RCC Idle ~-O
Next State (CHAN): Chnl Idle Messages:
Conc: Place circuit in idle state.
RCC: None.
CCU: Change channel (onhook) is sent to the CCU.
Actions:
This routine is invoked whenever a subscriber station generates a Clear Request. The channel state is set to Chnl Idle. The clear-request timer is cancelled. Whether or not teardown was in progress, the RCU considers the subscriber station available for another call, and returns the RCC state to RCC Idle.
Place Call Origination (place) Current State: RCC Idle Token: Call Request i339157 Next State (RCC): Active Next State (CHAN): Offhk Syn Wait Messages:
Conc: Place circuit in loop state.
RCC: Send Call Connect message to Subscriber Station.
CCU: Send Change Channel (OFFHOOK).
Actions:
This routine is invoked when a Subscriber Station is in the RCC
Idle state and the RCU receives a Call Request token. A Change Channel message with an Offhook status is sent to the CCU, and a Call Connect message is sent to the Subscriber Station. The channel state of the allocated frequency is set to Offhk Syn Wait, and the RCC state is set to Active.
- Subscriber Stati~n Call Accept (s accp) Current State: Page Token: Call Accept Next State (RCC): Active Next State (CHAN): Ring Syn Wait Messages:
Conc: Place circuit in loop state.
RCC: Send Call Connect message.
CCU: Send Change Channel (RING).
Actions:
This routine is invoked when the RCU receives a Call Accept token from a Subscriber Station that is in the Page state. The page timer is cancelled. A Change Channel message with Ring status is sent to the CCU, and a Call connect message is sent to the Subscriber Station. The channel state is set to Ring Syn Wait, and the RCC state is set to Active.
l339l57 Subscriber Station Page (s_page) Current State: RCC Idle l339l57 Token: Incoming Ring Next State (RCC): Page Next State (CHAN): No state change Messages:
Conc: None.
RCC: Send a Page message if the Subscriber Station.
CCU: None Actions:
If an Incoming Ring token is received from the concentrator while the Subscriber Station is in the RCC
Idle state, then this routine is invoked. The line appearance is mapped to a predetermined Page message, which is then transmitted to the appropriate Subscriber Station.
A timer is set in case the Subscriber Station does not respond to the page. The RCC state is set to Page.
The following group of descriptions define some of the channel state transition routines which are called whenever a token is received from a CCU.
1339ls7 Subscriber Station Ring Trip (rng_offhk) Current State: Syn Ring, Ring Syn Wait Token: Sync Offhook Next State (RCC): No state change Next State (CHAN): Syn Offhk Messages:
Conc: None.
RCC: None.
CCU: Send Change Channel (OFFHOOK) to the CCU.
Actions:
This routine is activated when a Subscriber Station is in the ring state and either in or out of synchronization, and the RCU receives 13~9157 a message that the Subscriber Station is now in synchronization and has transitioned to Offhook. Normally, when a Sync Offhook token is received, the Subscriber Station is already in synchronization. The CCU
is sent a Change Channel message with Offhook status, and the channel state is changed to Syn Offhk.
Subscriber Station Sync Offhook (syn offhk) Current State: Offhk Syn Wait Token: Sync Offhook Next State (RCC): No state change lo Next State (CHAN): Syn Offhk Messages:
Conc: None.
RCC: None.
CCU: None.
Actions:
This routine generates no messages, it only causes a change in channel state to Sync Offhk.
Subscriber Station Sync Ring (syn ring) Current State: Ring Syn Wait Token: Sync Ring 13391~7 Next State (RCC): No state change Next State (CHAN): Syn Ring Messages:
Conc: None.
RCC: None.
CCU: None.
Actions:
This routine changes the channel state to Syn Ring.
The buffer 28 is connected to the remote ports of the remote lo concentrator 27 via line pairs 46-49 and to the ~h~nnel modules 21 of the communication circuit 14 via lines 57 for directing the transmitted and recieved voice signals between the predetermined remote ports of the remote concentrator 27 and the predetermined communication channel time slots assigned to predetermined subscriber stations 51. The subscriber stations 51 are located remotely from the base station.
The buffer 28 includes a separate buffer unit, as shown in Figure 2, for interfacing with each channel module 21 in the communication circuit 12. The timing generator 30 provides the channel interface module 32 with a clock signal CLK and four gate signals Gate 0, Cate 1, Gate 2, Gate 3 for defining four sequentially repetitive time slots in the assigned communication ch~nnel.
The transmitted voice signal line pairs 46, the received voice signal line pairs 47, and the the signalling data line pairs 48, 49 are connected between the remote ports of the concentrator 27 and the channel interface module 32.
The channel interface module 32 provides the clock and gate signals to the channel module 27 for defining the time slots assigned by the CCU 24.
The channel interface module 32 is connected to the VCU 23 in the corresponding channel module 21 in a predetermined manner for directing communications between line pairs 46, 47 carrying transmitted and received voice signals associated with a given subscriber station and a codec in the VCU 23 having the predetermined communication channel time slot assigned by the CCU 24 to the given subscriber station. The channel interface module is further connected to the VCU 23 for directing the signalling data between the signalling data line pairs 48, 49 and the the voice codec in the VCU having the common time slot ~,o assigned by the CCU 24 for communicating signalling data ~or all three subscriber stations associated with the given channel module.
~l
Claims (18)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for communicating between subscriber stations and an external network; comprising a central terminal in communication with said external communication network, a processor in said central terminal communicating with a communication terminal for directing communications between said central terminal and said communication terminal;
a plurality of channel modules in said communication terminal in communication with a greater plurality of subscriber stations via RF communication frequencies having multiple time slots, time slots being assigned to subscriber stations as needed;
at least one controller in said communication terminal for directing communications between the channel modules and the central terminal wherein, said central terminal and said communication terminal are in communication with each other via bit streams generated and received by each, bit streams transmitted by said central terminal to said communication terminal containing signals initiated from said external network and bit streams transmitted by said communication terminal to said central terminal containing signals initiated from said subscriber stations, said bit streams containing multiple sequentially repetitive time slots; and a control channel (BCC) between said central terminal and said communication terminal for transmitting control signals which can be initiated by both terminals.
a plurality of channel modules in said communication terminal in communication with a greater plurality of subscriber stations via RF communication frequencies having multiple time slots, time slots being assigned to subscriber stations as needed;
at least one controller in said communication terminal for directing communications between the channel modules and the central terminal wherein, said central terminal and said communication terminal are in communication with each other via bit streams generated and received by each, bit streams transmitted by said central terminal to said communication terminal containing signals initiated from said external network and bit streams transmitted by said communication terminal to said central terminal containing signals initiated from said subscriber stations, said bit streams containing multiple sequentially repetitive time slots; and a control channel (BCC) between said central terminal and said communication terminal for transmitting control signals which can be initiated by both terminals.
2. An apparatus according to claim 1, wherein said controller is connected to the channel modules over a path carrying a plurality of channels and acts to interface with said channel modules for directing signals between time slots in said RF communication frequencies and channels on said path.
3. An apparatus according to claim 1, wherein at least one of said terminals includes a concentrator.
4. An apparatus according to claim 1, wherein the central terminal is remotely located from the communication terminal.
5. An apparatus for communication between subscriber stations and an external communication network having a plurality of ports, comprising at least one trunk for providing a communication channel between an exchange and a terminal, said terminal having at least one controller;
said controller being coupled to a plurality of channel modules and providing multiple sequentially repetitive time slots in RF channels, the time slots being assigned to subscriber stations in accordance with a predetermined assignment routine in response to an incoming call or call request, thereby enabling concurrent communications from the plurality of ports to be applied to subscriber stations;
the exchange connecting the trunk to the external communication network ports; wherein a processor is coupled to the exchange by a base station control channel for causing the exchange to complete a connection between a given external communication network port and the controller by means of a time slot on the communication channel;
the plurality of channel modules coupling the communication signals to given subscriber stations via the radio frequency (RF) channels;
the channel modules are respectively coupled by the controller to time slots of the communication channel carried over the trunk and to assigned time slots of the radio frequency channels.
said controller being coupled to a plurality of channel modules and providing multiple sequentially repetitive time slots in RF channels, the time slots being assigned to subscriber stations in accordance with a predetermined assignment routine in response to an incoming call or call request, thereby enabling concurrent communications from the plurality of ports to be applied to subscriber stations;
the exchange connecting the trunk to the external communication network ports; wherein a processor is coupled to the exchange by a base station control channel for causing the exchange to complete a connection between a given external communication network port and the controller by means of a time slot on the communication channel;
the plurality of channel modules coupling the communication signals to given subscriber stations via the radio frequency (RF) channels;
the channel modules are respectively coupled by the controller to time slots of the communication channel carried over the trunk and to assigned time slots of the radio frequency channels.
6. An apparatus according to claim 5, wherein the exchange comprises a concentrator.
7. An apparatus according to claim 5, further comprising control means to decrease jitter and to control slips in the received signals.
8. An apparatus as in claim 7, further comprising a frame buffer containing a plurality of frames, wherein a selected address within each frame corresponds to a selected channel assignment, said frames having an initial predetermined separation.
9. An apparatus according to claim 5, further comprising an echo canceller for cancelling echoes in voice signals communicated over the trunk; wherein the processor is coupled to the echo canceller for enabling the operation of the echo canceller during only those time slots that have been assigned by the processor to carry voice signals.
10. An apparatus as in claim 5, wherein each channel module couples a plurality of RF
time slots to a corresponding plurality of subscriber stations according to an allocation routine; and wherein said allocation routine includes allocating all of the RF time slots associated with a given channel module before allocating time slots associated with another channel module.
time slots to a corresponding plurality of subscriber stations according to an allocation routine; and wherein said allocation routine includes allocating all of the RF time slots associated with a given channel module before allocating time slots associated with another channel module.
11. An apparatus as in claim 5, and further comprising a control channel between the exchange and the communication terminal for transmitting control signals therebetween.
12. An apparatus as in claim 6, wherein a communication signal processor is coupled to given subscriber stations by the channel module in response to command signals from the processor, said processor sending said command signal in response to an incoming call or call request and is respectively coupled by the controller to predetermined time slots.
13. An apparatus as in claim 12, wherein the communication signal processor provides a predetermined signal pattern in its predetermined time slot when not coupled by its channel module to its subscriber station, and wherein the exchange is responsive to a command from the processor causing a signal received by the exchange from one of the communication signal processors over a given time slot to be looped back to the communication signal processor coupled to that time slot; and wherein the communication signal processor is coupled to the channel module for enabling the channel module to receive commands from the processors in response to a said looped-back predetermined signal pattern for assigning the communication signal processor to communicate with a given subscriber station.
14. An apparatus according to claim 13, wherein the processor comprises means for assigning a given time slot to a given subscriber station, said assigning means including means for commanding the exchange to loop back signals received from the communication signal processor coupled to the given time slot;
means for sending an address initialization signal over the control channel to all of the channel modules to store in address associated with the given subscriber station in the channel module that is enabled in response to the communication signal processor coupled thereto receiving said looped-back predetermined signal pattern; and means for commanding the channel module in which the address is stored to assign the given time slot coupled communication signal processor to the given subscriber station.
means for sending an address initialization signal over the control channel to all of the channel modules to store in address associated with the given subscriber station in the channel module that is enabled in response to the communication signal processor coupled thereto receiving said looped-back predetermined signal pattern; and means for commanding the channel module in which the address is stored to assign the given time slot coupled communication signal processor to the given subscriber station.
15. An apparatus according to claim 14, wherein each channel module includes means for responding to storage of said address by sending an acknowledgement to the processor; and wherein the processor further includes means for commanding the exchange to loop back signals received from the communication signal processor coupled to a different given time slot when no acknowledgement is received from the channel module coupled to the communication signal processor coupled to the first recited given time slot.
16. An apparatus in claim 5, wherein in response to the central channel the channel module communicates control signals to a subscriber station over a radio control channel allocated to a given RF time slot of a given frequency channel by the processor.
17. An apparatus according to claim 5, wherein the controller and the channel modules are modular for enabling their addition to and removal from the system in accordance with changes in the number of subscriber stations with which the base station communicates.
18. An apparatus according to claim 5, wherein said exchange is remotely located from the terminal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000615508A CA1339157C (en) | 1988-03-28 | 1989-10-04 | Connection of subscriber communication network base station to external information network |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA562633 | 1988-03-28 | ||
| CA000615508A CA1339157C (en) | 1988-03-28 | 1989-10-04 | Connection of subscriber communication network base station to external information network |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000615508A Division CA1339157C (en) | 1988-03-28 | 1989-10-04 | Connection of subscriber communication network base station to external information network |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000615508A Division CA1339157C (en) | 1988-03-28 | 1989-10-04 | Connection of subscriber communication network base station to external information network |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1339157C true CA1339157C (en) | 1997-07-29 |
Family
ID=4137732
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000615508A Expired - Lifetime CA1339157C (en) | 1988-03-28 | 1989-10-04 | Connection of subscriber communication network base station to external information network |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1339157C (en) |
-
1989
- 1989-10-04 CA CA000615508A patent/CA1339157C/en not_active Expired - Lifetime
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