Adaptive handover measurement interval
AssigneeNokia Corporation
InventorsHarri J Pekonen, Jussi Vesma
Life of this patent
Estimating the term…
Abstract
Apparatus and methods are provided for adaptively determining a handover measurement interval. Power savings are achieved when a mobile terminal in a digital broadcast broadband network does not constantly attempt to measure the signal strength of nearby cells. By determining cell parameters, such as size and carrier frequency, and also determining dynamic information, such as signal strength and mobile speed over time, the time until the next handover measurement is adjusted up or down. When a mobile terminal is moving towards a transmitter in a cell, the handover measurement interval may be lengthened, and when a mobile terminal is moving away from a transmitter, the interval may be shortened.
Claims27
A method comprising:
- determining cell parameters for a current cell, wherein the current cell broadcasts a broadband digital signal;
- determining a handover measurement interval based on the cell parameters;
- determining that a signal is scheduled to be received at a predetermined time;
- adjusting the handover measurement interval so that a handover measurement is scheduled to coincide with the predetermined time;
- and
- measuring a signal quality of one or more candidate cells at a time varying based on the handover measurement interval.
An apparatus comprising:
- a receiver configured to receive a digital broadband broadcast signal from a transmitter in a current cell;
- a processor configured to:
- determine parameters for the current cell;
- determine a handover measurement interval based on the current cell parameters;
- determine that a signal is scheduled to be received at a predetermined time;
- adjust the handover measurement interval so that a handover measurement is scheduled to coincide with the predetermined time;
- and
- schedule a handover measurement at a time based on the handover measurement interval.
An apparatus comprising:
- a receiver configured to receive digital broadband broadcast burst signals from a transmitter in a cell;
- a memory configured to store information relevant to the cell;
- and
- a processor, configured to:
- determine a size of the cell;
- retrieve signal quality measurements from the receiver;
- store signal quality measurements in the memory;
- determine a handover measurement interval based on the size of the cell;
- adjust the handover measurement interval based on the signal quality measurements stored in the memory;
- and
- schedule handover measurements at a time based on the handover measurement interval.
An apparatus, comprising:
- circuitry configured to perform the following:
- determining a speed of the apparatus moving through a current cell by performing the following:
- receiving a channel impulse response of a Doppler shifted signal;
- performing a Fast Fourier Transform on the channel impulse response to produce a Doppler power spectrum;
- estimating a Doppler spread frequency based on the Doppler power spectrum;
- and
- calculating the speed of the apparatus by dividing the Doppler spread frequency by a carrier frequency and multiplying the resulting ratio by the speed of light;
- and
- determining at least a portion of a handover measurement interval based on the speed of the apparatus.
One or more computer readable media storing computer code that, when executed, cause a computer to perform a method comprising:
- determining parameters for a current cell;
- determining a handover measurement interval based on the parameters;
- determining that a signal is scheduled to be received at a predetermined time;
- adjusting the handover measurement interval so that a handover measurement is scheduled to coincide with the predetermined time;
- and
- measuring the signal quality of one or more candidate cells at a time varying based on the handover measurement interval.
Dependencies are inferred from the claim text.