Call set-up in a transmission trunking radio system

• US 5,697,058 A
• Filed: 05/25/1995
• Issued: 12/09/1997
• Est. Priority Date: 11/27/1992
• Status: Expired due to Fees

• Current Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Original Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Inventors: Paavonen, Tapio
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US08/446,635
• Time in Patent Office: 929 Days
• Field of Search: 455/34.1, 455/34.2, 455/54.1, 455/54.2, 455/67.1, 455/63, 370/17, 370/85.3, 370/85.2
• US Class Current: 455/509
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

A call control method in a transmission trunking radio system, in which (i) M traffic channels are simultaneously allocated to at most N mobile stations for a call, N and M being positive integers and N>M; and (ii) a mobile station is commanded to go onto one of the M traffic channels during a call for the duration of the call transactions only and onto a control channel at other times. The number N of calls can be optimized by (iii) collecting data about collisions of call transactions of different calls on the M traffic channels, and (iv) automatically adjusting the maximum number N of simultaneously allowed calls in accordance with the collected data.

Claims

1. A call control method in a transmission trunking radio system, comprising the steps of:

sharing M traffic channels by simultaneous on-going calls of N mobile stations in maximum according to a transmission trunking method, N and M being positive integers and N>

M;

requesting traffic channel for each call transaction by said mobile stations via a control channel during said calls;

allocating to any one of said N mobile stations requesting a traffic channel any one of said M traffic channels, if available, for a duration of a call transaction, and deallocating said traffic channel and commanding said one mobile station to return onto said control channel after completion of said call transaction;

registering collision of call transactions, if the radio system, due to a lack of available traffic channels, fails to immediately allocate any one of said M traffic channels to any one of said N mobile stations requesting a traffic channel;

collecting data about collisions of call transactions of different calls on said M traffic channels; and

automatically adjusting the allowed maximum number N of simultaneous calls in accordance with the collected data.

2. The method of claim 1, further comprising the steps of:

initiating the call transaction by activating a pressel in the mobile station; and

terminating the call transaction by releasing the pressel in the mobile station.

3. The method of claim 1, further comprising the step of:

adjusting the allowed maximum number N of simultaneous calls in accordance with the number of collisions of call transactions.

4. The method of claim 3, further comprising the step of:

adjusting the allowed maximum number N of simultaneous calls in accordance with the frequency of collisions of call transactions.

5. The method of claim 3 further comprising the step of:

adjusting the allowed maximum number N of simultaneous calls in accordance with a ratio of such channel allocation attempts which have caused collisions to the total number of allocation attempts in a time unit.

6. The method of claim 1, further comprising the step of:

adjusting the allowed maximum number N of simultaneous calls in accordance with the frequency of collisions of call transactions.

7. The method of claim 6, further comprising the step of:

adjusting the allowed maximum number N of simultaneous calls in accordance with the ratio of such channel allocation attempts which have caused collisions to a total number of allocation attempts in a time unit.

8. The method of claim 1, further comprising the step of:

adjusting the allowed maximum number N of simultaneous calls in accordance with a ratio of such channel allocation attempts which have caused collisions to the total number of allocation attempts in a time unit.

9. The method of claim 1, wherein said step of adjusting comprises, in connection with every channel allocation attempt, the further steps of:

measuring a time elapsed since a previous collision;

integrating the maximum number N of simultaneous calls downwards if the allocation attempt causes collision of call transactions; and

integrating the maximum number N of simultaneous calls upwards if the allocation does not cause collision of call transactions.

10. Transmission trunking radio system, comprising:

a plurality of base station sites;

a plurality of mobile stations;

at least one of said base station sites having at least one control channel and at least M traffic channels for shared use of simultaneous on-going calls of N mobile stations in maximum according to a transmission trunking method, N and M being positive integers and N>

M;

said N mobile stations being arranged to request traffic channel for each call transaction via said control channel during said calls;

a call control unit arranged to allocate to any one of said N mobile stations requesting a traffic channel any one of said M traffic channels, if available, for a duration of a call transaction, and to deallocate said traffic channel and to command said one mobile station to return onto said control channel after completion of said call transaction;

means for collecting data on collisions of call transactions of different calls on said M traffic channels, a collision of call transactions being detected, if said call control unit, due to a lack of available traffic channels, fails to immediately allocate any one of said M traffic channels to any one of said N mobile stations requesting a traffic channel; and

means for automatically adjusting the allowed maximum number of simultaneous calls in accordance with the collected data.