Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
2001-08-10
2003-10-21
Vuong, Quochien (Department: 2685)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S426100, C455S343200, C455S574000, C370S311000
Reexamination Certificate
active
06636745
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of wireless communications and, more particularly, to shortening call-setup time in wireless communication systems that page call participants.
BACKGROUND OF THE INVENTION
Many battery powered communication units have a sleep mode in which they are able to conserve power by powering down components such as their receivers. These communication units then “wake up” periodically to determine if any messages (pages) are going to be transmitted to them. If there are no messages that the communication unit needs to receive, it will power down in order to extend its battery life. Next generation Code-Division Multiple-Access (CDMA) cellular communication systems, more commonly referred to as CDMA 2000 or Wideband CDMA systems, incorporate such power saving techniques. Each communication unit within a CDMA 2000 system is normally able to determine to which group of four, 20 millisecond (ms), synchronous frames on its paging channel (PCH) it is assigned. This group of frames, referred to as its “paging slot,” is used by the infrastructure to transmit messages to the particular unit. Thus, a communication unit in so-called “slotted mode” operation exits its sleep mode in order to monitor transmissions associated with its assigned paging slot. The more quickly a communication unit can determine that it has no messages or no more messages to receive, the more quickly it can return to sleep mode and conserve power, further extending its battery life.
CDMA 200 also incorporates a Quick Paging Channel (QPCH) to reduce the time a communication unit must monitor the PCH. QPCH slots comprise four, 20 millisecond (ms), synchronous frames. However, QPCH frames are transmitted 100 ms earlier than their corresponding PCH slot. A couple of paging indicator bits are transmitted in the QPCH slot that tell each communication unit whether it may be addressed by any of the upcoming PCH messages. Because the QPCH does not employ error correction coding or interleaving as the PCH does, the time required for a communication unit to receive and process its bits is small compared to the time required to monitor the PCH slot. Thus, the QPCH allows communication units to determine whether they need to monitor the upcoming corresponding PCH slot at all. Normally, a large number of communication units determine, based on the QPCH indicators, that they do not need to monitor the PCH during the upcoming corresponding slot and they can rapidly re-enter a “sleep mode,” where battery power is conserved.
While the QPCH enables communication units to save battery life, it also introduces 100 ms of delay (on average) to call-setup time. For dispatch calls, however, call-setup time is very important. A dispatch user expects to “push-to-talk” and begin conversing with other call participants in a very short period of time, usually 1 second or less. Thus, a communication unit, a communication infrastructure, and method that shorten this call-setup time while still providing the benefit of the QPCH are needed.
REFERENCES:
patent: 6072987 (2000-06-01), Willey
patent: 6138034 (2000-10-01), Willey
patent: 6216004 (2001-04-01), Tiedemann, Jr. et al.
patent: 6317607 (2001-11-01), Tomcik et al.
patent: 6519239 (2003-02-01), Panchal et al.
patent: WO 99 67972 (1999-12-01), None
Sarkar, S. et al. “Phone Standby Time and The Quick Paging Channel.”IEEE International Symposium on Personal, Indoor and Mobile Radio Communications; vol. 3, Sep. 1999, pp. 1341-1345.
Sarkar, S. et al. “Soft Handoff on the Quick Paging Channel.”IEEE Global Telecommunications Conference—Globecom '99, pp. 2794-2798.
Crocker Ronald T.
Harris John M.
Oprescu-Surcobe Valentin
Jacobs Jeffrey K.
Motorola Inc.
Vuong Quochien
LandOfFree
Method and apparatus to shorten call-setup time does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus to shorten call-setup time, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus to shorten call-setup time will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3117602