Radio communication apparatus

• US 5,918,164 A
• Filed: 03/19/1997
• Issued: 06/29/1999
• Est. Priority Date: 09/09/1994
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Takahashi, Akira, Fujii, Hironori
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Armstrong, Darnell R.
• Application Number:
  US08/825,709
• Time in Patent Office: 832 Days
• Field of Search: 455/132, 455/133, 455/134, 455/135, 455/277.1, 455/277.2, 455/504, 455/506, 455/65
• US Class Current: 455/134
• CPC Class Codes: H04B 7/0814 based on current reception conditions, e.g. switching to different antenna when signal level is below threshold
• CPC Class Codes: H04B 7/082 selecting best antenna path

Abstract

A mean value of a received signal level is calculated by a mean value computing unit, a product of multiplying this received signal mean level by a prescribed ratio is calculated by a threshold computing unit and used as a first threshold value, and when the received signal level drops below this first threshold value, communication is performed by making a switch to an antenna that receives signals at a received signal level that is higher than the first threshold value. Switching of receiving antennas is not made when the received signal mean level calculated by the mean value computing unit falls below a second threshold value. This allows antenna switching to be performed in accordance with changes in the received signal level and prevents unnecessary antenna switching from being made when the level falls below the second threshold value.

Claims

1. A radio communication apparatus for use in a radio communication system, having a radio circuit, the apparatus comprising:

a first antenna connected with the radio circuit for receiving first and second signals, wherein the second signal is received earlier in time than the first signal;

a second antenna;

first detecting means for detecting a first level of the first signal and a second level of the second signal;

first average calculating means responsive to the first detecting means for calculating a first average level from the first and second levels;

comparing means responsive to the first average calculating means for comparing the first average level with a predetermined value; and

control means for maintaining a status in which the first antenna is connected with the radio circuit when the first average level is smaller than the predetermined value.

2. A radio communication apparatus for use in a radio communication system, having a radio circuit, the apparatus comprising:

a first antenna connected with the radio circuit for receiving first and second signals, wherein the second signal is received earlier in time than the first signal;

first detecting means for detecting a first level of the first signal and a second level of the second signal;

first average calculating means responsive to the first detecting means for calculating a first average level from the first and second levels;

a second antenna for receiving third and fourth signals, wherein the fourth signal is received earlier in time than the third signal;

second detecting means for detecting a third level of the third signal and a fourth level of the fourth signal;

second average calculating means responsive to the second detecting means for calculating a second average level from the third and fourth levels;

comparing means responsive to the first and second calculating means for comparing each of the first and second average levels with a predetermined value; and

control means for maintaining a status in which the first antenna is connected with the radio circuit only when each of the first and second average levels is smaller than the predetermined value.

3. A radio communication apparatus for use in a radio communication system, having a transmit circuit and a receive circuit, the apparatus comprising:

a first antenna for receiving first and second signals, wherein the second signal is received earlier in time than the first signal;

a second antenna;

selecting means for selecting one of the first and second antennas;

connecting means for selectively connecting the selecting means with the transmit circuit for a transmit period and selectively connecting the selecting means with the receive circuit for a receive period and selectively disconnecting the selecting means from any one of the transmit and receive circuits for an idle period, the first antenna being connected with the connecting means by the selecting means;

first detecting means for detecting a first level of the first signal and a second level of the second signal for the idle period;

first average calculating means responsive to the first detecting means for calculating a first average level of a signal received by the first antenna from at least the first and second levels;

comparing means responsive to the first average calculating means for comparing the first average level with a predetermined value; and

control means for maintaining a status in which the first antenna is connected with the connecting means when the first average level is smaller than the predetermined value.

4. The apparatus of claim 3, wherein the second antenna receives third and fourth signals, the fourth signal is received earlier in time than the third signal, the apparatus further comprising:

second detecting means for detecting a third level of the third signal and a fourth level of the fourth signal;

second average calculating means responsive to the second detecting means for calculating a second average level of a signal received by the second antenna from the third and fourth levels;

second comparing means responsive to the first and second average calculating means for comparing each of the first and second average levels with a second predetermined value; and

second control means for maintaining a status in which the first antenna is connected with the connecting means when each of the first and second average levels is smaller than the second predetermined value.

5. The apparatus of claim 4, wherein the second detecting means detects the third level and the fourth level for the idle period.