US6157836A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Portable communications and data terminal operating to optimize receipt of both incoming CDPD and AMPS messages
Assignee: Cirrus Logic Inc
•
Filing: 1998-09-30
•
Granted: 2000-12-05
•
Expires: 2018-09-30
Abstract
Abstract A portable radio telephone handset operates as a data transfer terminal as well as an analog cellular telephone subscriber station. Two modes of operation, an analog cellular communication mode and a Cellular Digital Packet Data (CDPD) mode, are available in the handset. The handset distinguishes between paging signals indicating CDPD mode communications and those indicating analog cellular communications. The handset also automatically preempts CDPD communications in favor of analog cellular communications such as those carried out in an AMPS configuration. The handset maintains an active status on a CDPD communication channel during a "sleep mode", when the handset can carry out AMPS activity.
Inventors
- 👤 Russell P. Cashman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:55
CPC Classifications
H; H04; H04W; H04W36/00; H04W36/0005; H04W36/0083; H04W36/0085; H04W36/0088; H04W68/00; H04W88/00; H04W88/02; H04W88/06
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
165 words
A method of affecting handoff of a wireless subscriber station from a first cell to a second cell in a Cellular Digital Packet Data (CDPD) system, where said wireless subscriber station contains a first cell transfer database pertaining to radio frequency characteristics of said first cell, said method comprising steps of: (a) sending a polling receiver ready (RR) signal from said wireless subscriber station to a CDPD Mobile Data Base Station (NDBS) in said second cell; (b) determining a first time interval for a complete Received Signal Strength Indication (RSSI) scan of said second cell by said wireless subscriber station; (c) dividing said first time interval into a plurality of sequential overlapping time slots; (d) alternately scanning said CDPD channel and an Advanced Mobile Phone Service (AMPS) control channel during successive time slots, thereby creating a second cell transfer data base transfer data base pertaining to said second cell; and (e) deleting said first cell transfer database upon acquisition of said second cell transfer database.
Claim 2
Independent Claim
165 words
A method of affecting handoff of a wireless subscriber station from a first cell to a second cell in a Cellular Digital Packet Data (CDPD) system, where said wireless subscriber station contains a first cell transfer database pertaining to radio frequency characteristics of said first cell, said method comprising steps of: (a) sending a polling receiver ready (RR) signal from said wireless subscriber station to a CDPD Mobile Data Base Station (NDBS) in said second cell; (b) determining a first time interval for a complete Received Signal Strength Indication (RSSI) scan of said second cell by said wireless subscriber station; (c) dividing said first time interval into a plurality of sequential overlapping time slots; (d) alternately scanning said CDPD channel and an Advanced Mobile Phone Service (AMPS) control channel during successive time slots, thereby creating a second cell transfer data base transfer data base pertaining to said second cell; and (e) deleting said first cell transfer database upon acquisition of said second cell transfer database.
Claim 3
Dependent Claim
72 words
The method of claim 1, wherein step (d) comprises substeps of: (i) repeating said alternating scan of said CDPD and AMPS control channels for at least a second time interval for a complete RSSI scan wherein scanning on said CDPD channels is carried out in timeslots not scanned for CDPD activity in said first time interval; and (ii) repeating sub-step (i) until all said time slots have been scanned for CDPD activity.
Claim 4
Dependent Claim
15 words
The method of claim 2, wherein each said time slot has the same time duration.
Claim 5
Dependent Claim
29 words
The method of claim 3, wherein said time slot duration is selected based upon intervals between transmission channel stream identification messages broadcast by said MDBS in said second cell.
Claim 6
Dependent Claim
24 words
The method of claim 2, wherein step (a) comprises the sub-steps of determining the number of CDPD channel streams existing in said second cell.
Claim 7
Dependent Claim
33 words
The method of claim 5, wherein said time slots are selected to be of unequal duration when said wireless subscriber station determines that a single CDPD channel stream exists in said second cell.
Claim 8
Dependent Claim
28 words
The method of claim 6, wherein said time slots used for scanning for AMPS activity have a greater duration than time slots used for scanning for CDPD activity.
Claim 9
Dependent Claim
43 words
The method of claim 2, further comprising the steps of: (f) selecting a second time interval greater than said first time interval; and (g) sending a polling RR from said subscriber station to said MDBS once during each of said second time intervals.
Claim 10
Dependent Claim
22 words
The method of claim 2, wherein said second time interval has a duration in the range of five minutes to one hour.
References Cited (Backward Citations)
US3564150A
Cited
US3575558A
Cited
US3627955A
Cited
US3906166A
Cited
US4005388A
Cited
US3976995A
Cited
US4095215A
Cited
US3976840A
Cited
US4268721A
Cited
US4352955A
Cited
US4279021A
Cited
US4613990A
Cited
US4661972A
Cited
US4802200A
Cited
US4850006A
Cited
US4812843A
Cited
US5168574A
Cited
US5115514A
Cited
US4825456A
Cited
US4962523A
Cited
US5203020A
Cited
US5054052A
Cited
US5257401A
Cited
US4947420A
Cited
US5212722A
Cited
US5128980A
Cited
WO1991007044A1
Cited
US5117449A
Cited
US5008925A
Cited
US5020091A
Cited
EP0439926A2
Cited
US5166973A
Cited
GB2241854A
Cited
US5247566A
Cited
GB2239567A
Cited
US5119397A
Cited
EP0473297A2
Cited
US5199031A
Cited
US5253287A
Cited
US5265270A
Cited
US5153903A
Cited
WO1992009178A1
Cited
US5396539A
Cited
US5228074A
Cited
EP0514360A2
Cited
US5349632A
Cited
EP0521609A2
Cited
EP0521610A2
Cited
US5148473A
Cited
GB2260064A
Cited
US5249218A
Cited
US5274699A
Cited
US5533029A
Cited
US5544222A
Cited
US5434853A
Cited
US5574979A
Cited
US5594943A
Cited
US5548805A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-12-05 | 2004-06-05 | 2004-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-12-05 | 2008-06-05 | 2008-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-12-05 | 2012-06-05 | 2012-12-05 | $7700.00 | Window Closed / Lapsed |