Adaptive synchronization arrangement

• US 5,184,347 A
• Filed: 07/09/1991
• Issued: 02/02/1993
• Est. Priority Date: 07/09/1991
• Status: Expired due to Term

• Current Assignee: Windward Corp. (Avaya Incorporated)
• Original Assignee: AT&T, Inc.
• Inventors: Ho, Kelvin K., Spencer, Douglas A., Heidebrecht, Richard M., Farwell, Charles Y., Hearn, Michel L.
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US07/727,491
• Time in Patent Office: 574 Days
• Field of Search: 370/93, 370/94.1, 370/100.1, 370/103, 370/18, 370/95.3, 370/95.1, 375/38, 375/40, 375/106, 375/107, 455/33.1, 455/33.2, 455/33.4, 455/51.1, 455/51.2, 455/54.1, 455/56.1, 455/69, 379/60, 379/63
• US Class Current: 370/350
• CPC Class Codes: H04J 3/0658 Clock or time synchronisation among packet nodes
• CPC Class Codes: H04J 3/0664 unidirectional timestamps
• CPC Class Codes: H04J 3/0673 using intermediate nodes, e.g. modification of a received timestamp before further transmission to the next packet node, e.g. including internal delay time or residence time into the packet
• CPC Class Codes: H04W 84/04 Large scale networks; Deep hierarchical networks

Abstract

A CDMA cellular radio-telephone system (FIG. 2) has switching systems (201) synchronized to public telephone network (100) timing signals (600), and radio telephones (203) and cell base stations (202) synchronized to different clock (1000). Transmission delays between the cell base stations and the telephone network are variable. Switching systems include digital communications interfaces (264) to the telephone system, whose connections to the telephone system are synchronized to the telephone system, and whose connections to the cells are nominally also synchronized to the telephone system but whose processor (602) operates for each call within predefined windows (1302, 1402) of phase relationships to the operation of the cell that is handling the call, and occasionally adjusts (FIGS. 13-16) its phase relationships to the operation of the telephone system to achieve and maintain its operation within the predefined windows. Packet-switched communications (350) between the cells and the switching systems absorb the phase relationship fluctuations and the timing adjustments in inter-packet intervals. Circuit-switched digital communications between the switching systems and the telephone system absorb the timing adjustments by means of vocoder (604)-implemented slips--bit insertions or deletions--in the communications traffic bit stream.

Claims

1. An apparatus comprising:

a first operating unit having its operations synchronized with first clock signals;

a second operating unit having its operations synchronized with second clock signals which are asynchronous with the first clock signals;

a third operating unit for interfacing the operations of the first unit with the operations of the second unit, the third unit having its operations nominally synchronized with the operations of the first unit;

means for monitoring an extent of asynchrony between the operations of the second and the third units, to determine whether the extent of asynchrony lies outside of a predetermined range of allowed asynchrony; and

means responsive to a determination that the extent of asynchrony does lie outside of the predetermined range, for adjusting the synchronization of the operations of the third unit with the operations of the first unit, to move the extent of asynchrony between the operations of the second and the third units to within the range.

2. An apparatus comprising:

first operating unit having its operations synchronized with first timing signals having a nominal frequency and a first phase;

second operating unit having its operations synchronized with second timing signals having the nominal frequency and a second phase different from and fluctuating with respect to the first phase;

third operating unit for interfacing the operations of the first unit with the operations of the second unit and having its operations synchronized with third timing signals having the nominal frequency and a third phase offset by an adjustably fixed amount from the first phase;

means for determining whether the third phase falls outside of a predetermined range of allowed offset from the second phase; and

means responsive to a determination that the third phase falls outside of the predetermined range, for adjusting the fixed offset of the third phase from the first phase to move the third phase within the range.

3. A communications system comprising:

a first unit for receiving incoming communication traffic at times dictated by first clock signals having a nominal frequency and a first phase;

a second unit for transmitting incoming communication traffic at times dictated by second clock signals having the nominal frequency and a second phase different from and fluctuating with respect to the first phase;

a third unit for interfacing communications between the first and the second units by transmitting to the first unit incoming communication traffic received from the second unit at times dictated by third clock signals having the nominal frequency and having a third phase that is offset by an adjustable fixed amount from the first phase;

first means for determining whether the third unit receives incoming communication traffic from the second unit within predetermined windows of time prior to the times of transmission by the third unit of the received incoming communication traffic; and

second means responsive to a determination that receptions of the incoming communication traffic at the third unit fall outside of the windows for either increasing or decreasing the amount of the offset of the third phase from the first phase to move the receptions into the windows.

4. The system of claim 3 wherein:

the second means adjust the offset at commencing of a communication in one step by any amount required to move the receptions substantially into centers of the windows, and adjust the offset during the communication in a series of sequential steps.

5. The system of claim 3 further comprising:

third means cooperative with the second means for inserting additional traffic into the incoming communication traffic received by the third unit and transmitting the additional traffic to the first unit while the amount of the offset is being increased, and for deleting a portion of the incoming communication traffic received by the third unit from the incoming communication traffic transmitted to the first unit while the amount of the offset is being decreased.

6. A communications system comprising:

a first unit for transmitting outgoing communication traffic at times dictated by first clock signals having a nominal frequency and a first phase;

a second unit for transmitting outgoing communication traffic at times dictated by second clock signals having the nominal frequency and a second phase different from and fluctuating with respect to the first phase;

a third unit for interfacing communications between the first and the second units by transmitting to the second unit outgoing communication traffic received from the first unit at times dictated by third clock signals having the nominal frequency and having a third phase that is offset by an adjustably fixed amount from the first phase;

first means for determining whether the second unit receives outgoing communication traffic from the third unit within predetermined windows of time prior to the times of transmission by the second unit of the received outgoing communication traffic; and

second means responsive to a determination that receptions of the outgoing communication traffic at the second unit fall outside of the windows for either increasing or decreasing the amount of the offset of the third phase from the first phase to move the receptions into the windows.

7. The system of claim 6 wherein:

the second means adjust the offset at commencing of a communication in one step by any amount required to move the receptions substantially into centers of the windows, and adjust the offset during the communication in a series of sequential steps.

8. The system of claim 6 further comprising:

third means cooperative with the second means for inserting additional traffic into the outgoing communication traffic transmitted from the first unit and causing the third unit to receive the additional traffic while the amount of the offset is being increased, and for deleting a portion of the outgoing communication traffic transmitted by the first unit from the outgoing communication traffic received by the third unit while the amount of the offset is being decreased.

9. A communications system comprising:

a first unit for transmitting outgoing communication traffic and receiving incoming communication traffic at times dictated by first clock signals having a nominal frequency and a first phase;

a second unit for transmitting received incoming and outgoing communication traffic at times dictated by second clock signals having the nominal frequency and a second phase different from and fluctuating with respect to the first phase;

a third unit for interfacing communications between the first and the second units by transmitting to the second unit outgoing communication traffic received from the first unit at times dictated by third clock signals having the nominal frequency and having a third phase that is offset by an adjustably fixed first amount from the first phase, and by transmitting to the first unit incoming communication traffic received from the second unit at times dictated by fourth clock signals having the nominal frequency and having a fourth phase that is offset by an adjustably fixed second amount from the first phase;

first means for determining whether the second unit receives outgoing communication traffic from the third unit within first predetermined windows of time prior to the times of transmission by the second unit of the received outgoing communication traffic;

second means for determining whether the third unit receives incoming communication traffic from the second unit within second predetermined windows of time prior to the times of transmission by the third unit of the received incoming communication traffic;

third means responsive to a determination that either receptions of the outgoing communication traffic at the second unit fall outside of the first windows or receptions of the incoming communication traffic at the third unit fall outside of the second windows for either increasing or decreasing the amount of the offset of either the third phase or the fourth phase from the first phase to move the receptions that fall outside of their corresponding windows into the corresponding windows.

10. The system of claim 9 wherein:

the third means are responsive to a determination by the first means that receptions of the outgoing communication traffic at the second unit lag the first windows, for decreasing the amount of the offset of the third phase from the first phase.

11. The system of claim 10 wherein:

the third means are further responsive to a determination by the first means that receptions of the outgoing communication traffic at the second unit lead the first windows, for increasing the amount of the offset of the third phase from the first phase.

12. The system of claim 9 wherein:

the third means are responsive to a determination by the second means that receptions of the incoming communication traffic at the third unit lag the second windows, for increasing the amount of the offset of the fourth phase from the first phase.

13. The system of claim 12 wherein:

the third means are further responsive to a determination by the second means that receptions of the incoming communication traffic at the third unit lead the second windows, for decreasing the amount of the offset of the fourth phase from the first phase.

14. The system of claim 9 wherein:

the third means adjust the first amount and the second amount of offset at commencing of a communication each in one step by any amount required to move the receptions that fall outside of their corresponding windows into the corresponding windows, and adjust the first amount and the second amount of offset during the communication in a series of sequential steps by an integral multiple of a same predetermined amount during each step.

15. The system of claim 9 further comprising:

fourth means cooperative with the third means for inserting additional traffic into the outgoing communication traffic transmitted from the first unit and causing the third unit to receive the additional traffic while the amount of the offset of the third phase is being increased and deleting a portion of the outgoing communication traffic transmitted by the first unit from the outgoing communication traffic received by the third unit while the amount of the offset of the third phase is being decreased, and for inserting additional traffic into the incoming communication traffic received by the third unit and transmitting the additionaal traffic to the first unit while the amount of the offset of the fourth phase is being increased and deleting a portion of the incoming communication traffic received by the third unit from the incoming communication traffic transmitted to the first unit while the amount of the offset of the fourth phase is being decreased.

16. The system of claim 9 wherein:

the first unit is for transmitting a stream of outgoing communication traffic and receiving a stream of incoming communication traffic;

the second unit is for transmitting packets of received incoming communication traffic, and receiving packets of outgoing communication traffic for transmission of the outgoing communication traffic;

the third unit includes

fourth means responsive to receipt of the stream of outgoing communication traffic from the first unit for packetizing the received outgoing communication traffic and transmitting the packets of the received outgoing communication traffic to the second unit at times dictated by the third clock signals, and

fifth means responsive to receipt of the packets of the incoming communication traffic from the second unit for depacketizing the received incoming communication traffic and transmitting the depacketized received incoming communication traffic toward the first unit at times dictated by the fourth clock signals;

the first means are for determining whether the second unit receives the packets of outgoing communication traffic from the third unit within the first predetermined windows; and

the second means are for determining whether the third unit receives the packets of incoming communication traffic from the second unit within the second predetermined windows.

17. A call-traffic processing apparatus for a cellular radio-telephone system that includes the apparatus, at least one cell each for transmitting first packets containing first frames of coded incoming call traffic received from a radio telephone to the apparatus and for transmitting to the radio telephone outgoing call traffic received from the apparatus in second packets containing second frames of coded outgoing call traffic, and a mobile-telephone switching system for interconnecting cells with each other and with a telephone network by routing a first digital stream of cells with each other and with a telephone network by routing a first digital stream of incoming call traffic received from the apparatus to a destination and by routing a second digital stream of outgoing call traffic received from a source to the apparatus, and wherein the first and the second digital streams are synchronized with first clock signals having a nominal frequency and a first phase and derived from the telephone network and the transmissions of the incoming and the outgoing call traffic by the cell are synchronized with second clock signals having the nominal frequency and a second phase that is different from and fluctuates with respect to the first phase, the call-traffic processing apparatus comprising:

outgoing vocoder means for receiving the second digital stream of outgoing call traffic synchronously with the first clock signals, coding the received outgoing call traffic, and transmitting second frames of the coded outgoing call traffic synchronously with third clock signals having the nominal frequency and a third phase that is offset by an adjustably fixed first amount from the first phase,

incoming vocoder means for receiving first frames of the coded incoming call traffic synchronously with fourth clock signals having the nominal frequency and a fourth phase that is offset by an adjustably fixed second amount from the first phase, decoding the received incoming call traffic, and transmitting the second digital stream of incoming call traffic synchronously with the first clock signals;

outgoing processing means for receiving the second frames of the coded outgoing call traffic from the outgoing vocoder means, packetizing the received second frames into the second packets, and transmitting the second packets to the cell synchronously with fifth clock signals having the nominal frequency and a fifth phase that is offset by an adjustably fixed third amount from the first phase;

incoming processing means for receiving the first packets from the cell, depacketizing the received first packets into the first frames, and transmitting the first frames to the incoming vocoder means synchronously with sixth clock signals having the nominal frequency and a sixth phase that is offset by an adjustably fixed fourth amount from the first phase;

clock signal generating means for deriving the third, the fourth, the fifth, and the sixth clock signals from the first clock signals;

first means for determining whether the incoming processing means receive the first packets within first predetermined windows of time prior to the times of transmission of the first frames by the incoming processing means to the incoming vocoder means;

second means for determining whether the cell receives the second packets within second predetermined windows of time prior to the times of transmission by the cell of the received outgoing call traffic to the mobile telephone; and

third means responsive to a determination that either receptions of the first packets fall outside of the first windows or receptions of the second packets fall outside of the second windows for causing the clock signal generating means to either increase or decrease the amounts of the offsets of either both the third and the fifth phases or both the fourth and the sixth phases, with respect to the first phase, to move the packet receptions that fall outside of their corresponding windows into the corresponding windows.

18. The apparatus of claim 17 wherein:

the third means are responsive to a determination by the first means that receptions of the first packets at the incoming processing means lag the first windows, for causing the clock signal generating means to increase the amounts of the offsets of both the fourth and the sixth phases from the first phase by a same amount.

19. The apparatus of claim 18 wherein:

the third means are responsive to a determination by the first means that receptions of the first packets at the incoming processing means lead the first windows, for causing the clock signal generating means to decrease the amounts of the offsets of both the fourth and the sixth phases from the first phase by a same amount.

20. The apparatus of claim 17 wherein:

the third means are responsive to a determination by the second means that receptions of the second packets at the packets at the cell lag the second windows, for causing the clock signal generating means to decrease the amounts of the offsets of both the third and the fifth phases from the first phase by a same amount.

21. The apparatus of claim 20 wherein:

the third means are responsive to a determination by the second means that receptions of the second packets at the cell lead the second windows, for causing the clock signal generating means to increase the amounts of the offsets of both the third and the fifth phases from the first phase by a same amount.

22. The apparatus of claim 17 wherein:

the third means cause the clock signal generating means to adjust either the first and the third amounts of offset or the second and the fourth amounts of offset, in one step by any amount required to move any packet receptions that fall outside of their corresponding windows into the corresponding windows at a commencing of a communication, and cause the clock signal generating means to adjust either the first and the third amounts of offset or the second and the fourth amounts of offset by an integral multiple of a same predetermined amount in each step of a series of sequential steps to move packet receptions that fall outside of their corresponding windows into the corresponding windows during the communication.

23. The apparatus of claim 17 further including:

means cooperative with the third means for causing the outgoing vocoder means to insert traffic additional to the outgoing call traffic received by the outgoing vocoder means into second frames transmitted by the outgoing vocoder means while the amounts of the offsets of the third and the fifth phases are being increased, causing the outgoing vocoder means to delete a portion of the outgoing call traffic received by the outgoing vocoder means from the second frames transmitted by the outgoing vocoder means while the amounts of the offsets of the third and fifth phases are being decreased, causing the incoming vocoder means to insert traffic additional to the incoming call traffic received by the incoming vocoder means into the first digital stream transmitted by the incoming vocoder means while the amounts of the offsets of the fourth and the sixth phase are being increased, and causing the incoming vocoder means to delete a portion of the incoming call traffic received by the incoming vocoder means from the first digital stream transmitted by the incoming vocoder means while the amounts of the offsets of the fourth and the sixth phase are being decreased.

24. A method of operating an apparatus that comprises a first operating unit, a second operating unit, and a third operating unit for interfacing the operations of the first unit with the operations of the second unit, the method comprising the steps of:

synchronizing operations of the first operating unit with first clock signals;

synchronizing operations of the second operating unit with second clock signals which are asynchronous with the first clock signals;

nominally synchronizing operations of the third unit with the operations of the first unit;

monitoring an extent of asynchrony between the operations of the second and the third units, to determine whether the extent of asynchrony lies outside of a predetermined range of allowed asynchrony; and

adjusting the synchronization of the operations of the third unit with the operations of the first unit, in response to a determination that the extent of asynchrony does lie outside of the predetermined range, to move the extent of asynchrony between the operations of the second and the third units to within the range.

25. The method of claim 24 wherein:

the step of synchronizing operations of the first unit comprises the step of

synchronizing the operations of the first operating unit with first timing signals having a nominal frequency and a first phase;

the step of synchronizing operations of the second unit comprises the step of

synchronizing the operations of the second operating unit with second timing signals having the nominal frequency and a second phase different from and fluctuating with respect to the first phase;

the step of nominally synchronizing operations of the third unit comprises the step of

synchronizing operations of the third operating unit with third timing signals having the nominal frequency and a third offset by an adjustably fixed amount from the first phase;

the step of monitoring comprises the step of

determining whether the third phase falls outside of a predetermined range of allowed offset from the second phase; and

the step of adjusting comprises the step of

adjusting the fixed offset of the third phase from the first phase, in response to a determination that the third phase falls outside of the predetermined range, to move the third phase to within the range.

26. A method of operating a communications system comprising a first unit for transmitting incoming communications, a second unit for receiving incoming communications, and a third unit for interfacing communications between the first and the second units, the method comprising the steps of:

transmitting incoming communication traffic from the first unit at times dictated by first clock signals having a nominal frequency and a first phase different from and fluctuating with respect to a second phase;

receiving the transmitted incoming communication traffic at the third unit;

transmitting from the third unit to the second unit incoming communication traffic received from the first unit at times dictated by second clock signals having nominal frequency and having a third phase that is offset by an adjustably fixed amount from the second phase;

receiving incoming communication traffic transmitted from the third unit at the second unit at times dictated by third clock signals having the nominal frequency and the second phase;

determining whether the third unit receives incoming communication traffic from the first unit within predetermined windows of time prior to the times of transmission by the third unit of the received incoming communication traffic; and

either increasing or decreasing the amount of the offset of the third phase from the second phase, in response to a determination that receptions of the incoming communication traffic at the third unit fall outside of the windows, to move the receptions into the windows.

27. A method of claim 26 wherein

the step of either increasing or decreasing the amount of the offset comprises the steps of:

adjusting the offset at commencing of a communication in one step by any amount required to move the receptions substantially into centers of the windows; and

adjusting the offset during the communication in a series of sequential steps.

28. The method of claim 26 further comprising the steps of :

inserting additional traffic into the incoming communication traffic received by the third unit transmitting the additional traffic to the second unit while the amount of the offset is being increased; and

deleting a portion of the incoming communication traffic received by the third unit from the incoming communication traffic transmitted to the second unit while the amount of the offset is being decreased.

29. A method of operating a communications system comprising a first unit for transmitting communications, a second unit for receiving outgoing communications, and a third unit for interfacing communications between the first and the second units, the method comprising the steps of:

transmitting outgoing communication traffic from the first unit at times dictated by the first clock signals having nominal frequency and a first phase;

receiving at the third unit the outgoing communication traffic transmitted by the first unit;

transmitting from the third unit to the second unit outgoing communication traffic received from the first unit at times dictated by second clock signals having the nominal frequency and having a second phase that is offset by an adjustably fixed amount from the first phase;

receiving at the second unit the outgoing communication traffic transmitted by the third unit;

transmitting outgoing communication traffic from the second unit at times dictated by third clock signals having the nominal frequency and a third phase different from and fluctuating with respect to the first phase;

determining whether the second unit receives outgoing communication traffic from the third unit within predetermined windows of the time prior to the times of transmission by the second unit of the received outgoing communication traffic; and

either increasing or decreasing the amount of the offset of the second phase from the first phase, in the response to a determination that receptions of the outgoing communication traffic at the second unit fall outside of the windows, to move the receptions into the windows.

30. The method of claim 29 wherein

the step of either increasing or decreasing the amount of the offset comprises the steps of:

adjusting the offset at commencing of a communication in one step by any amount required to move the receptions substantially into centers of the windows; and

adjusting the offset during the communication in a series of sequential steps.

31. The method of claim 29 further comprising the steps of:

inserting additional traffic into the outgoing communication traffic transmitted from the first unit causing the third unit to receive the additional traffic while the amount of the offset is being increased; and

deleting a portion of the outgoing communication traffic transmitted by the first unit from the outgoing communication traffic received by the third unit while the amount of the offset is being decreased.

32. A method of operating a communications system comprising a first unit for transmitting outgoing communication traffic and receiving incoming communication traffic, a second unit for transmitting received incoming and outgoing communication traffic, and a third unit for interfacing communications between the first and the second units, the method comprising the steps of:

transmitting outgoing communication traffic from the first unit and receiving incoming communication traffic at the first unit at times dictated by first clock signals having a nominal frequency and a first phase;

transmitting received incoming and outgoing communication traffic from the second unit at times dictated by the second clock signals having the nominal frequency and a second phase different from and fluctuating with respect to the first phase;

receiving at the third unit the outgoing communication traffic transmitted by the first unit;

transmitting from the third unit to the second unit outgoing communication traffic received from the first unit at times dictated by third clock signals having the nominal frequency and having a third phase that is offset by an adjustably fixed first amount from the first phase;

receiving at the third unit the incoming communication traffic transmitted by the second unit;

transmitting from the third unit to the first incoming communication traffic received from the second unit at times dictated by fourth clock signals having the nominal frequency and having a fourth phase that is offset by an adjustably fixed second amount from the first phase;

determining whether the second unit receives outgoing communication traffic from the unit within first predetermined windows of the time prior to the times of transmission by the second unit of the received outgoing communication traffic;

determining whether the third unit receives incoming communication traffic from the second unit within second predetermined windows of time prior to the times of transmission by the third unit of the received incoming communication traffic; and

either increasing or decreasing the amount of the offset of either the third phase or the fourth phase from the first phase, in response to a determination that either receptions of the outgoing communication traffic at the second unit fall outside of the first windows or receptions of the incoming communication traffic at the third unit fall outside of the second windows, to move the receptions that fall outside of their corresponding windows into the corresponding windows.

33. The method of claim 32 wherein

the step of either increasing or decreasing the amount of the offset comprises the step of:

decreasing the amount of the offset of the third phase from the first phase, in response to a determination that receptions of the outgoing communication traffic at the second unit lag the first windows.

34. The method of claim 33 wherein

the step of either increasing or decreasing the amount of the offset further comprises the step of:

increasing the amount of the offset of the third phase from the first phase, in response to a determination that receptions of the outgoing communication traffic at the second unit lead the first windows.

35. The method of claim 32 wherein

the step of either increasing or decreasing the amount of the offset comprises the step of:

increasing the amount of the offset of the fourth phase from the first phase, in response to a determination that receptions of the incoming communication traffic at the third unit lag the second windows.

36. The method of claim 35 wherein

the step of either increasing or decreasing the amount of the offset further comprises the step of:

decreasing the amount of the offset of the fourth phase from the first phase, in response to a determination that receptions of the incoming communication traffic at the third unit lead the second windows.

37. The method of claim 32 wherein

the step of either increasing or decreasing the amount of the offset comprises the step of:

adjusting the first amount and the second amount of the offset at commencing of a communication each in one step by any amount required to move the receptions that fall outside of their corresponding windows into the corresponding windows; and

adjustment the first amount and the second amount of offset during the communication in a series of sequential steps by an integral multiple of the same predetermined amount during each step.

38. The method of claim 32 further comprising the steps of:

inserting additional traffic into the outgoing communication traffic transmitted from the first unit and causing the third unit to receive the additional traffic while the amount of the offset of the third phase is being increased;

deleting a portion of the outgoing communication traffic transmitted by the first unit from the outgoing communication traffic received by the third unit while the amount of the offset of the third phase is being decreased;

inserting additional traffic into the incoming communication traffic received by the third unit and transmitting the additional traffic to the first unit while the amount of the offset of the fourth phase is being increased; and

deleting a portion of the incoming communication traffic received by the third unit from the incoming communication traffic transmitted to the first unit while the amount of the offset of the fourth phase is being decreased.

39. The amount of claim 32 in a communications system wherein the first unit is for transmitting a stream of outgoing communication traffic and receiving a stream of incoming communication traffic, and the second unit is for transmitting packets of received incoming communication traffic, and receiving packets of outgoing communication traffic for transmission of the outgoing communication traffic, wherein:

the step of receiving at the third unit the outgoing communication traffic transmitted by the first means comprises the steps of

receiving the stream of outgoing communication traffic from the first unit, and

packetizing the received outgoing communication traffic;

the steps of transmitting from the third unit to the second unit outgoing communication traffic comprises the step of

transmitting the packets of the received outgoing communication traffic to the second unit at times dictated by the third clock signals;

the step of receiving at the third unit the incoming communication traffic transmitted by the second unit comprises the steps of

receiving the packets of the incoming communication traffic from the second unit, and

depacketizing the received incoming communication traffic;

the step of transmitting from the third unit to the first incoming communication traffic comprises the step of

transmitting the depacketized received incoming communication traffic toward the first unit at times dictated by the fourth clock signals;

the step of determining whether the second unit receives outgoing communication traffic comprises the step of

determining whether the second unit receives the packets of outgoing communication traffic from the third unit within the first predetermined windows; and

the step of determining whether the third unit receives incoming communication traffic comprises the steps of

determining whether the third unit receives the packets of incoming communication traffic from the second unit within the second predetermined windows.

40. A method of processing call traffic in an interface arrangement of a cellular radio-telephone system that includes the arrangement, at least one cell each for transmitting first packets containing first frames of coded incoming call traffic received from a radio telephone to the arrangement and for transmitting to the radio telephone outgoing call traffic received from the arrangement in second packets containing second frames of coded outgoing call traffic, and a mobile-telephone switching system for interconnecting cells with each other and with a telephone network by routing a first digital stream of incoming call traffic received from the arrangement to a destination and by routing a second digital stream of outgoing call traffic received from a source to the arrangement and wherein the first and the second digital streams are synchronized with first clock signals having a nominal frequency and a first phase and derived from the telephone network and the transmissions of the incoming and the outgoing call traffic by the cell are synchronized with second clock signals having the nominal frequency and a second phase that is different from and fluctuates with respect to the first phase, the method comprising the steps of:

receiving the second digital stream of outgoing call traffic synchronously with the first clock signals;

coding the received outgoing call traffic;

transmitting second frames of the coded outgoing call traffic synchronously with third clock signals having the nominal frequency and a third phase that is offset by an adjustably fixed first amount from the first phase;

receiving the second frames of the coded outgoing call traffic;

packetizing the received second frames into the second packets;

transmitting the second packets to the cell synchronously with fifth clock signals having the nominal frequency and a fifth phase that is offset by an adjustably fixed third amount from the first phase;

receiving the first packets from the cell;

depacketizing the received first packets into the first frames;

transmitting the first frames synchronously with sixth clock signals having the nominal frequency and a sixth phase that is offset by an adjustably fixed fourth amount from the first phase;

receiving the first frames of coded incoming call traffic synchronously with fourth clock signals having the nominal frequency and a fourth phase that is offset by an adjustably fixed second amount from the first phase;

decoding the received incoming call traffic;

transmitting the second digital stream of incoming call traffic synchronously with the first clock signals;

determining whether the interface arrangement receives the first packets within first predetermined windows of time prior to the times of transmission of the first frames by the interface arrangement;

determining whether the cell receives the second packets within second predetermined windows of time prior to the times of transmission by the cell of the received outgoing call traffic to the mobile telephone; and

either increasing or decreasing the amounts of the offsets of either both the third and the fifth phases or both the fourth and the sixth phases, with respect to the first phase, in response to a determination that either receptions of the first packets fall outside of the first windows or receptions of the second packets fall outside of the second windows, to move the packet receptions that fall outside of their corresponding windows into the corresponding windows.

41. The method of claim 40 wherein

the step of either increasing or decreasing the amounts of the offsets comprises the step of:

increasing the amounts of the offsets of both the fourth and the sixth phases from the first phase by a same amount, in response to a determination that receptions of the first packets at the interface arrangement lag the first windows.

42. The method of claim 41 wherein

the step of either increasing or decreasing the amounts of the offsets further comprises the step of:

decreasing the amounts of the offsets of both the fourth and the sixth phases from the first phase by a same amount, in response to a determination that receptions of the first packets at the interface arrangement lead the first windows.

43. The method of claim 40 wherein

the step of either increasing or deceasing the amounts of the offsets comprises the step of:

decreasing the amounts of the offsets of both the third and the fifth phases from the first phase by a same amount, in response to a determination that receptions of the second packets at the cell lag the second windows.

44. The method of claim 43 wherein

the step of either increasing of decreasing the amounts of the offsets further comprises the step of:

increasing the amounts of the offsets of both the third and the fifth phases from the first phase by a same amount, in response to a determination that receptions of the second packets at the cell lead the second windows.

45. The method of claim 40 wherein

the step of either increasing or decreasing the amounts of the offsets comprises the steps of:

adjusting either the first and the third amounts of offset or the second and the fourth amounts of offset, in one step by any amount required to move any packet receptions that fall outside of their corresponding windows into the corresponding windows at a commencing of a communication; and

adjusting either the first and the third amounts of offset or the second and the fourth amounts of offset by an integral multiple of a same predetermined amount in each step of a series of sequential steps to move packet receptions that fall outside of their corresponding windows into the corresponding windows during the communication.

46. The method of claim 40 further comprising the steps of:

inserting traffic additional to the outgoing call traffic into the second frames while the amounts of the offsets of the third and the fifth phases are being increased;

deleting a portion of the outgoing call traffic from the second frames while the amounts of the offsets of the third and the fifth phases are being decreased;

inserting traffic additional to the incoming call traffic into the first digital stream while the amounts of the offsets of the fourth and the sixth phases are being increased; and

deleting a portion of the incoming call traffic from the first digital stream while the amounts of the offsets of the fourth and the sixth phases are being decreased.