Browse Prior Art Database

Begrenzung der Verlustleistung eines HF-Leistungsverstaerkers im Multislot Betrieb durch Beschraenkung der Anzahl der TX Slots in Abhaengigkeit spezifischer Umgebungsbedingungen

IP.com Disclosure Number: IPCOM000029117D
Original Publication Date: 2004-Jul-25
Included in the Prior Art Database: 2004-Jul-25
Document File: 2 page(s) / 28K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

In a mobile phone being operated in GPRS (Radio Frequency) class 12 mode (4TX) the heat generation caused by the RF (Radio Frequency) power amplifier can not be neglected despite the reduction of maximum output power in multi slot mode (e.g. up to 6dB for 4TX). Detailed evaluations show that permanent class 12 operation in HTR (High Temperature Range) is not feasible with standard components even at NCD (Normal Conditions for PA Power Dissipation). Only short-term operation is possible in HTR whereby the duration depends on dissipated power and ambient temperature. The evaluations are valid for the case that no special HW (hardware) measures are implemented inside the phone to reduce power dissipation of RF power amplifier (e.g. buck converter, switched matching, high efficiency PA). If the critical temperature is exceeded it's compulsory to reduce the power dissipation to prevent the PA or other components from being damaged by overheat or to avoid that these components are operated outside their specified temperature range. The reduction of dissipation power can be achieved by reducing GPRS class or PA output power. The reduction of GPRS class is advantageous, because it is preferred to continue transmission with reduced data rate than to increase the risk of dropped packet transfer due to low radiated power. Changing the GPRS class during data transfer is not supported by every base station. So it is necessary to reduce the PA output power if the request to change GPRS class is ignored by the base station. Derating the output power results in reduced radiated power which increases the risk of dropped packet transfer.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 2

S

Begrenzung der Verlustleistung eines HF-Leistungsverstaerkers im Multislot Betrieb durch Beschraenkung der Anzahl der TX Slots in Abhaengigkeit spezifischer Umgebungsbedingungen

Idea: Andreas Langer, DE-Muenchen; Christian Bildl, DE-Muenchen

In a mobile phone being operated in GPRS (Radio Frequency) class 12 mode (4TX) the heat generation caused by the RF (Radio Frequency) power amplifier can not be neglected despite the reduction of maximum output power in multi slot mode (e.g. up to 6dB for 4TX). Detailed evaluations show that permanent class 12 operation in HTR (High Temperature Range) is not feasible with standard components even at NCD (Normal Conditions for PA Power Dissipation). Only short-term operation is possible in HTR whereby the duration depends on dissipated power and ambient temperature. The evaluations are valid for the case that no special HW (hardware) measures are implemented inside the phone to reduce power dissipation of RF power amplifier (e.g. buck converter, switched matching, high efficiency PA).

If the critical temperature is exceeded it's compulsory to reduce the power dissipation to prevent the PA or other components from being damaged by overheat or to avoid that these components are operated outside their specified temperature range. The reduction of dissipation power can be achieved by reducing GPRS class or PA output power. The reduction of GPRS class is advantageous, because it is preferred to continue transmission with reduced data rate than to increase the risk of dropped packet transfer due to low radiated power. Changing the GPRS class during data transfer is not supported by every base station. So it is necessary to reduce the PA output power if the request to change GPRS class is ignored by the base station. Derating the output power results in reduced radiated power which increases the risk of dropped packet transfer.

A major finding is that in HTR and class 12 mode the critical temperature will be exceeded for NCD. So after a few minutes it is unavoidable to reduce either output power or GPRS class. Such behavior is highly critical since reproducible call drops may occur due to reduction of radiated power. Therefor it makes no sense to support class 12 in HTR since stable operation can not be guaranteed even for NCD. In NTR (Normal Temperature Range) permanent class 12 operation for NCD is feasible. Only for ECD (Extreme Conditions for PA Power Dissipation) critical temperature states may occur.

The objective of the invention report is to bring out a device and method to adapt the number of supported TX slots depending on environmental conditions like ambient temperature and antenna mode. The method shall compromise between number of supported TX slots and QoS (Quality of Service) which depends on radiated power and data rate.

As al...