Modularly clustered radiotelephone system

• US 5,528,585 A
• Filed: 05/15/1995
• Issued: 06/18/1996
• Est. Priority Date: 09/30/1993
• Status: Expired due to Term

• Current Assignee: David M. Cooley, David Vessal, Eric Johns, John D. Kaewell, Joseph J. Digiovanni, Mark A. Lemmo, Michael W. Regensburg, Scott D. Kurtz
• Original Assignee: David M. Cooley, David Vessal, Eric Johns, John D. Kaewell, Joseph J. Digiovanni, Mark A. Lemmo, Michael W. Regensburg, Scott D. Kurtz
• Inventors: Cooley, David M., Lemmo, Mark A., Kaewell, John D., Regensburg, Michael W., Kurtz, Scott D., DiGiovanni, Joseph J., Johns, Eric, Vessal, David
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Jung, Min
• Application Number:
  US08/441,220
• Time in Patent Office: 400 Days
• Field of Search: 370/50, 370/95.1, 370/95.3, 370/69.1, 370/85.6, 370/56, 379/58
• US Class Current: 370/347
• CPC Class Codes: H04B 1/1615 Switching on; Switching off, e.g. remotely battery saving circuits associated with selective call operation H04W52/00; details of power consumption reduction in a PLL, H03L7/0802, H03L7/14, H03L2207/08, H03L2207/18; muting amplifiers by gain control see H03G3/34
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04J 3/0685 Clock or time synchronisation in a node; Intranode synchronisation
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/56 based on priority criteria
• CPC Class Codes: H04W 74/0891 for synchronized access
• CPC Class Codes: H04W 84/14 WLL [Wireless Local Loop]; RLL [Radio Local Loop]
• CPC Class Codes: H04W 88/00 Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
• CPC Class Codes: H04W 88/021 adapted for Wireless Local Loop operation
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A power-conserving time division multiple access (TDMA) radio telephone system is disclosed in which a cluster of subscriber stations, remote from a base station, employs a common pool of frequency-agile modems each of which digitally synthesizes, on a timeSlot-by-timeSlot basis, the different channel-identifying intermediate frequencies needed to support communications between several of the subscriber stations and the base station. Power conservation is facilitated inter alia by controlling the assignment of modems to calls, maintaining unassigned modems in a powered-down state and by controlling the number of calls using the same time slot. Delay in assigning a powered-down modem to a call is eliminated by making available to all modems the highest quality synchronization information obtained by any of the active modems.

Claims

1. In a radio telephone system having a central office base station, a plurality of remote subscriber stations, means defining a repetitive set of time slots for supporting radio telephone calls between said subscriber stations and said central office station, a group of modems, each of said modems being capable of handling a plurality of said telephone calls on successive ones of said time slots, the process of assigning said time slots to said calls, comprising the steps of:

a. ascertaining which active modems have idle time slots;

b. assigning preference ratings to said idle time slots at said group of modems;

c. ascertaining which of said time slots has the highest of said preference ratings;

d. assigning the time slot corresponding to said ascertained highest preference rating to the next one of said calls.

2. In a radio telephone system having a central office base station, a plurality of remote subscriber stations, means defining a repetitive set of time slots for supporting radio telephone calls between said subscriber stations and said central office station, a group of modems, each of said modems being capable of handling a plurality of said telephone calls on successive ones of said time slots, the process of assigning said time slots to said calls comprising the steps of:

a. ascertaining which active modems have idle time slots;

b. assigning preference ratings to said idle time slots at said group of modems;

c. ascertaining which of said time slots has the highest of said preference ratings;

d. assigning the time slot corresponding to said ascertained highest preference rating to the next one of said calls;

wherein said step of assigning said preference ratings includes the steps of;

i. ascertaining which time slots are in use by

more than one modem;

ii. ascertaining which modems have adjacent time slots available to handle a call;

iii. ascertaining whether a modem has a time slot available to handle the synchronization task.

3. The process of assigning time slots to calls according to claim 2 wherein said step of assigning said preference ratings assigns the highest priority to a slot which is (a) available on an active modem, (b) is not a slot available for the synchronization task, (c) leaves adjacent slots available for QPSK calls and (d) does not increase the number of modems using a slot beyond a predetermined threshhold.

4. The process of assigning time slots to calls according to claim 3 wherein said step of assigning said preference ratings assigns the second highest priority to a slot which is (a) available on an active modem, (b) leaves adjacent slots available for QPSK calls, and (c) does not increase the number of modems using a slot beyond a predetermined threshhold.

5. The process of assigning time slots to calls according to claim 4 wherein said step of assigning said preference ratings assigns the third highest priority to a slot which is (a) available on an active modem and (b) leaves adjacent slots available for QPSK calls.

6. The process of assigning time slots to calls according to claim 5 wherein said step of assigning said preference ratings assigns the fourth highest priority to a slot which is available on an active modem.