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METHOD FOR ADJUSTING TRANSMIT POWER IN HALF-DUPLEX MOBILE RADIOS

IP.com Disclosure Number: IPCOM000242375D
Original Publication Date: 2015-Jul-10
Included in the Prior Art Database: 2015-Jul-10
Document File: 3 page(s) / 55K

Publishing Venue

Motorola

Related People

Jurzak, Pawel: INVENTOR [+2]

Abstract

Half-duplex mobile radio typically transmits call with the default transmit power even though the power could be reduced when mobile radio is close to the base station and/or RF conditions are good. On the other hand transmit power shall be increased quickly when audio fades condition due to transitional obstacles (like a tunnel, building etc.). The method described in this publication allows half-duplex mobile radios to dynamically adjust transmit power during a call by extending the power control loop with additional mobile device in proximity. Mobile radio in proximity receives information about transmission quality like Received Signal Strength Indicator (RSSI)/Bit Error Rate (BER)/Carrier Squelch(CSQ) or simple instructions to gain/lower down transmit power, embedded by base station in downlink frames and provides this data to transmitting mobile radio via wired connection or wireless short range protocol (WiFi, Bluetooth, etc) so that the transmitting half-duplex mobile radio can efficiently adjust transmit power during the call. The proxy mobile device may be one of the subscribers involved in group or individual communication sourced by transmitting mobile radio, or it may be other mobile device utilizing different Radio Access Technology (RAT) and/or Radio Access Network (RAN). In some embodiments both radio modems could be embedded in one mobile device, like for example device combining Land Mobile Radio (LMR) and Long Term Evolution (LTE) RATs capabilities in single device.

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METHOD FOR ADJUSTING TRANSMIT POWER IN HALF-DUPLEX MOBILE RADIOS

by Pawel Jurzak, Grzegorz Szyszka

Motorola Solutions, Inc.

 

ABSTRACT

A half-duplex mobile radio typically transmits with the default transmit power even though the power could be reduced when the mobile radio is close to the base station and/or RF conditions are good. On the other hand, transmit power needs to be increased quickly when audio fades due to transitional obstacles (like a tunnel, building etc.).

The method described in this publication allows half-duplex mobile radios to dynamically adjust transmit power during a call by extending the power control loop with an additional mobile device in close proximity.

A mobile radio in proximity receives information about transmission quality like Received Signal Strength Indicator (RSSI)/Bit Error Rate (BER)/Carrier Squelch(CSQ) or simple instructions to gain/lower down transmit power, embedded by base station in downlink frames and provides this data to transmitting mobile radio via wired connection or wireless short range protocol (WiFi, Bluetooth, etc) so that the transmitting half-duplex mobile radio can efficiently adjust transmit power during the call.

The proxy mobile device may be one of the subscribers involved in group or individual communication sourced by a transmitting mobile radio, or it may be other mobile device utilizing different Radio Access Technology (RAT) and/or Radio Access Network (RAN).

In some embodiments both radio modems could be embedded in one mobile device, like for example device combining Land Mobile Radio (LMR) and Long Term Evolution (LTE) RATs capabilities in single device.

PROBLEM

A transmitting radio with excess transmit power drains the battery quickly and may cause unnecessary interference. On the other hand, not enough transmit power may cause signal fades and this can lead to audio issues or loss of data.

Therefore, it is important to adjust mobile radio transmit power to save the battery power and improve the user’s experience.

Adjusting transmit power in a half-duplex mobile radio commonly used today may be difficult as such mobile radio cannot transmit and receive a signal simultaneously, especially as it cannot get feedback related to its signal quality received by base station when transmitting.

The above problem exists in both conventional and trunked FDMA systems like P25 Phase 1 and DMR systems Tier I and II. Even though it is possible to establish power feedback loop between mobile radio and base station in some TDMA trunked systems, like P25 Phase 2, TETRA and DMR Tier III, it may not be sufficient as opportunity to receive power feedback from base station may be too rare to efficiently adjust transmit power and to avoid signal fades.

SOLUTION

The solution is to extend the power control loop by adding additional mobile devices in proximity to transmitting device as a proxy between base station and that device. Such a proxy can be a mobile radio installed in a car or portable...