# US 8,786,352 B2 · Threshold computation apparatus and threshold computation program

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- Number: US 8,786,352 B2
- Document ID: US8786352B2
- Status: Granted
- Kind: B2
- Application number: 13/402,155
- Filed: 2012-02-22
- Published: 2012-08-30
- Granted: 2014-07-22
- Earliest claimed: 2011-02-24
- Assignees: Kddi Corporation
- Applicants: Toshihiko Komine; Toshiaki Yamamoto; Satoshi Konishi
- Inventors: Toshihiko Komine; Toshiaki Yamamoto; Satoshi Konishi
- Web page: https://patentgrep.com/patent/US8786352B2

## CPC

- H04W 36/008375: {based on historical data}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A threshold computation apparatus obtains estimated interference power for an uplink from a terminal to a base station; a predetermined communication quality value necessary for the uplink; a maximum value of transmission power of the terminal; and transmission power of the base station for a downlink from the base station to the terminal. The apparatus subtracts a logarithmic value of the maximum value of the transmission power of the terminal from a logarithmic value of the transmission power of the base station for the downlink; adds a logarithmic value of the communication quality value and a logarithmic value of the estimated interference power to a result of the subtraction; and determines a result of the addition to be a logarithmic value of received power at the terminal; and computes a threshold based on the logarithmic value of the received power at the terminal and predetermined conditions.

## Claims

### Claim 1

A threshold computation apparatus comprising:
an estimator configured to compute and output estimated interference power that is an estimated value of interference power for an uplink as a communication link from a terminal to a base station;
a storage unit configured to store a predetermined communication quality value necessary for the uplink, a maximum value of transmission power of the terminal, and transmission power of the base station for a downlink as a communication link from the base station to the terminal;
a received power computation unit that is connected to the estimator and the storage unit, configured to:
obtain the estimated interference power from the estimator; the predetermined communication quality value; the maximum value of transmission power of the terminal; and the transmission power of the base station from the storage;
subtract a logarithmic value of the maximum value of the transmission power of the terminal from a logarithmic value of the transmission power of the base station for the downlink; adds a logarithmic value of the communication quality value and a logarithmic value of the estimated interference power to a result of the subtraction; and
determine a result of the addition to be a logarithmic value of received power at the terminal; and
a threshold computation unit that is connected to the received power computation unit and configured to compute a threshold based on the logarithmic value of the received power at the terminal and a predetermined condition.

### Claim 2 (depends on 1)

The threshold computation apparatus in accordance with claim 1, wherein: the threshold computation unit sends the threshold via a communication apparatus to the terminal, where the threshold is used in a determination as to whether or not the terminal will send the base station, information necessary for a determination as to whether or not a handover process should be executed.

### Claim 3 (depends on 1)

The threshold computation apparatus in accordance with claim 1, wherein: the threshold computation unit sends the threshold via a communication apparatus to the terminal, where the threshold is used in a determination as to whether or not the terminal will select a base station which the terminal accesses.

### Claim 4 (depends on 1)

The threshold computation apparatus in accordance with claim 1, wherein: the threshold computation unit sends the threshold via a communication apparatus to the terminal, where the threshold is used in a determination as to whether or not the terminal will send the base station, information used in a determination as to whether or not a different system or a different frequency band should be searched for by the terminal.

### Claim 5

A non-transitory computer-readable storage medium which stores a threshold computation program that makes a computer execute:
a received power computation process that:
obtains estimated interference power that is an estimated value of interference power for an uplink as a communication link from a terminal to a base station; a predetermined communication quality value necessary for the uplink; a maximum value of transmission power of the terminal; and transmission power of the base station for a downlink as a communication link from the base station to the terminal;
subtracts a logarithmic value of the maximum value of the transmission power of the terminal from a logarithmic value of the transmission power of the base station for the downlink;
adds a logarithmic value of the communication quality value and a logarithmic value of the estimated interference power to a result of the subtraction; and
determines a result of the addition to be a logarithmic value of received power at the terminal; and
a threshold computation process that computes a threshold based on the logarithmic value of the received power at the terminal and a predetermined condition.