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A Method For Extending The Battery Life For Mobile Terminals With Stringent Call Setup Time Requirements

IP.com Disclosure Number: IPCOM000005671D
Original Publication Date: 2001-Oct-24
Included in the Prior Art Database: 2001-Oct-24
Document File: 3 page(s) / 305K

Publishing Venue

Motorola

Related People

Valentin Oprescu-Surcobe: AUTHOR [+2]

Related Documents

US6041241: PATENT

Abstract

Reducing call setup time is a general objective that is unrelated to radio technology, be it 2G, 2.5G, 3G or beyond. However, the requirement is more stringent for dispatch services (push-to-talk), which, in many cases, are mobile-to-mobile calls, thus involving paging. Since most of the mobile stations monitor paging channels in slotted mode to preserve battery life, the length of the paging slotting cycle may easily become a significant component of the overall call setup time. The obvious solution, reducing the length of the slotting cycle, comes at the price of reduced battery life. This paper proposes a very simple, yet effective and practical way, to reduce the paging slotting cycle in circumstances when power is not at a premium.

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                  A Method For Extending The Battery Life For Mobile Terminals With Stringent Call Setup Time Requirements

by Valentin Oprescu-Surcobe and Ronald Crocker

Abstract

Reducing call setup time is a general objective that is unrelated to radio technology, be it 2G, 2.5G, 3G or beyond. However, the requirement is more stringent for dispatch services (push-to-talk), which, in many cases, are mobile-to-mobile calls, thus involving paging. Since most of the mobile stations monitor paging channels in slotted mode to preserve battery life, the length of the paging slotting cycle may easily become a significant component of the overall call setup time. The obvious solution, reducing the length of the slotting cycle, comes at the price of reduced battery life. This paper proposes a very simple, yet effective and practical way, to reduce the paging slotting cycle in circumstances when power is not at a premium.

Call setup time vs. battery life

The figure below shows the theoretical dependencies between the call setup time and the standby battery time, when the repetition period for the paging time slot changes between 80 and 1280 ms. It is clear that requiring lower call setup times results in lower paging slot times, and consequently in increased power consumption.

Dynamic adjustment of the slot cycle

Even for a mobile station, power is not always at a premium: e.g. a mobile station that is installed in a car (or temporarily plugged in) can use a lower paging time slot period, without any penalty. The trend to ban the use of cell phones while driving, except if they use hands-free operation, will likely result in more and more cell phones either permanently installed in the cars or temporarily docked there. Such cell phones will run off the power provided by the car, and in these cases, the amount of power that they use is not important. As such, a smaller paging time slot period can be adopted, resulting in faster delivery for call terminations. It is proposed that mobile stations detect when they start operating off external power rather than own battery and use the event to reduce their paging slot period. The mobile station will start operating in slotted mode at a lower paging slot period or start working in non-slotted mode (i.e. monitor the paging channel continuously). The event of moving from own battery to an external power source could trigger a notification to the infrastructure of the new paging time slot period observed by the mobile station. The notification will typically take the form of a registration, in which the new slotting parameters will be communicated to the infrastructure. The infrastructure will send pages and individually addressed messages in the slots that are determined based on the new information.

The mobile station may provide a way to disable this capability in case it is not desi...