Communication units, integrated circuits and methods therefor

Patent metadata

Field	Value
Publication number	US-2016183154-A1
Application number	US-201414907546-A
Country	US
Kind code	A1
Filing date	Jul 23, 2014
Priority date	Jul 23, 2013
Publication date	Jun 23, 2016
Grant date	—

Abstract

A wireless communication unit capable of moving between communication cells is described. The wireless communication unit comprises: a receiver arranged to receive a wireless signal; and a controller operably coupled to the receiver and comprising a layer 1 filtering module and a layer 3 filtering module. The controller is arranged to implement on the received wireless signal both: layer 1 filtering by the layer 1 filtering module at a physical layer; and layer 3 filtering by the layer 3 filtering module at a radio resource control layer. The layer 3 filtering module is operably coupled to a gradient calculation module arranged to calculate a gradient change that is representative of at least one of: a rate of change of received signal strength with a serving cell; a rate of received signal strength difference between a neighbour cell and a serving cell, such that at least a portion of layer 3 filtering of the received wireless signal is based on the calculated gradient change.

First claim

1 . A wireless communication device configured to move between communication cells, the wireless communication device comprising:
a receiver configured to receive a wireless signal; and a controller operably coupled to the receiver and comprising a layer 1 filtering device and a layer 3 filtering device, wherein the controller is configured to implement on the received wireless signal the layer 1 filtering by the layer 1 filtering device at a physical layer and the layer 3 filtering by the layer 3 filtering device at a radio resource control layer, wherein the layer 3 filtering device is operably coupled to a gradient calculation device configured to calculate a gradient change that is representative of at least one of: a rate of change of received signal strength with a serving cell, or a rate of received signal strength difference between a neighbor cell and a serving cell, such that at least a portion of layer 3 filtering of the received wireless signal is based on the calculated gradient change.

2 . The wireless communication device of claim 1 , wherein the layer 3 filtering device is configured to apply a filtering coefficient representative of a gradient change of the received wireless signal.

3 . The wireless communication device of claim 1 , wherein the layer 3 filtering device is operably coupled to the gradient calculation device configured arranged to calculate a gradient change that is representative of the rate of received signal strength difference between the neighbor cell and the serving cell at substantially equal time intervals.

4 . The wireless communication device of claim 1 , wherein the layer 3 filtering device is configured to provide a first output to a measurement evaluation device and a second output to the measurement evaluation device via the gradient calculation device such that the layer 3 filtering is arranged to smooth a calculated gradient change.

5 . The wireless communication device of claim 1 , wherein the layer 1 filtering device comprises at least a first output and a second output, wherein the first output is provided to a measurement evaluation device via at least a first portion of the layer 3 filtering device and the second output is provided to the measurement evaluation device via the gradient calculation device.

6 . The wireless communication device of claim 5 , wherein the first output is configured to provide an update to the measurement evaluation device every 40 ms averaged over the last 200 ms.

7 . The wireless communication device of claim 5 , wherein the second output of the layer 1 filtering device is configured to provide to the measurement evaluation device additionally via at least a second portion of the layer 3 filtering device.

8 . The wireless communication device of claim 4 , wherein the gradient calculation device is configured to output a gradient change value to a scaling calculation device configured to scale one or more parameters when the measurement evaluation device is performing measurement evaluation.

9 . The wireless communication device of claim 1 , wherein the layer 3 filtering device is divided into a plurality of layer 3 filtering devices, with at least one of the plurality of layer 3 filtering devices is configured to apply layer 3 filtering after the gradient calculation device calculates a gradient change.

10 . The wireless communication device of claim 9 , wherein at least one of the plurality of layer 3 filtering device is configured to apply layer 3 filtering before the gradient calculation device calculates a gradient change.

11 . The wireless communication device of claim 10 , wherein an output of the at least one of the plurality of layer 3 filtering devices configured to apply layer 3 filtering before the gradient calculation device is only used as input for the gradient calculation device.

12 . The wireless communication device of claim 5 , wherein the scaling calculation device is configured to determine from a number (m) of samples of the gradient change values whether a minimum portion (n) of the number of samples is reached to trigger a scaling operation.

13 . The wireless communication device of claim 12 , wherein the scaling calculation device is configured to scale the gradient change value in response to the minimum portion (n) exceeding a threshold.

14 . The wireless communication unit of claim 13 , wherein the scaling calculation device is arranged to scale the gradient change value to expedite handover in response to the minimum portion (n) exceeding a first threshold and avoid handover if the minimum portion (n) exceeds a second threshold.

15 . The wireless communication device of claim 5 , wherein the scaling calculation device is configured to apply a ratio based hysteresis scaling when determining whether to transition between two of: an expedite handover state, an avoid handover state, or a normal no gradient calculation state.

16 . The wireless communication device of claim 1 , wherein the controller is configured to not consider previous calculated gradient values or scaling values when performing at least one of: gradient specific filtering or ratio based gradient scaling upon an occurrence of a specific event.

17 . The wireless communication device of claim 16 , wherein the specific event comprises one of: a change of communication cell through handover, a change of communication cell through re-establishment, or a passing through a center of the communication cell resulting in a change in a sign of the calculated gradient value.

18 . The wireless communication device of claim 16 , wherein in response to the specific event the gradient change calculation is reset.

19 . The wireless communication device of claim 1 , further comprising a memory operably coupled to the controller and configured to store filtering parameters of layer 3 filtering device in order to facilitate layer 3 filtering.

20 . The wireless communication device of claim 1 , wherein the wireless communication device is configured to operate in a heterogeneous network comprising a plurality of macro cells and a plurality of small cells deployed on the same frequency.

21 . A method implemented by a wireless communication device to reduce a number of handovers of a wireless communication device configured to move between communication cells, the method comprising:
receiving a wireless signal; performing on the received wireless signal:
layer 1 filtering by a layer 1 filtering device at a physical layer, and
layer 3 filtering by a layer 3 filtering device at a radio resource control layer; and
calculating a gradient change that is representative of at least one of:
a rate of change of received signal strength with a serving cell, or
a rate of received signal strength difference between a neighbor cell and a serving cell such that at least a portion of layer 3 filtering of the received wireless signal is based on the calculated gradient change.

22 . A base station to reduce a number of handovers of a wireless communication device capable of moving between communication cells, the base station comprising:
a transmitter configured to send instructions to a wireless communication device, and a signal processing device operably coupled to the transmitter and configured to generate the instructions, wherein the instructions instruct the wireless communication device to perform at least one unfiltered measurement or at least one measurement to be filtered at both a layer 1 physical layer

Assignees

• Samsung Electronics Co Ltd

Inventors

• Van Der Velde Himke
• Van Lieshout Gert Jan
• Jeong Kyeong-Ln
• Ingale Mangesh Abhimanyu

Classifications

• H04W36/0083

  Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists · CPC title

• H04W36/30 Primary

  by measured or perceived connection quality data · CPC title

• H04L69/325

  in the network layer [OSI layer 3], e.g. X.25 (H04L69/16 takes precedence) · CPC title

• H04W36/04

  Reselecting a cell layer in multi-layered cells · CPC title

• H04W36/304

  due to measured or perceived resources with higher communication quality · CPC title