Radio communication system

• US 6,763,062 B1
• Filed: 05/23/2000
• Issued: 07/13/2004
• Est. Priority Date: 05/24/1999
• Status: Expired due to Term

• Current Assignee: Ryuji Kohno, Toshiba Tec Corporation (Toshiba Corporation)
• Original Assignee: Ryuji Kohno, Toshiba Tec Corporation (Toshiba Corporation)
• Inventors: Kohno, Ryuji, Mochizuki, Hiroki
• Primary Examiner(s): Corrielus, Jean B.
• Assistant Examiner(s): GHULAMALI, QUTBUDDIN
• Application Number:
  US09/576,291
• Time in Patent Office: 1,512 Days
• Field of Search: 375/219, 375/220, 375/221, 375/222, 375/261, 375/264, 375/285, 370/334
• US Class Current: 375/220
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]

Abstract

When the average received signal level falls below a given threshold level, a received level detecting/monitoring section informs a microprocessor of it. The microprocessor then collects information of the arrival direction and received power of desired radiation from each terminal station and the arrival direction and received power of undesired radiation from each source of undesired radiation and recalculates amplitude and phase weight values. The microprocessor rewrites weight values already entered into a weight value table by the recalculated weight values to thereby alter amplitude and phase weight values for antenna elements of an array antenna. Thereby, the directivity of the array antenna is subjected to optimum control according to variations in electromagnetic radiation propagation environment, allowing good radio communications at all times.

Claims

1. In a radio communication system comprising a base station having an array antenna including a plurality of antenna elements, a receiving section which weights the amplitude and phase of each of received signals from the plurality of antenna elements by amplitude and phase weight values of each of the antenna elements set in the receiving section, then combines the weighted signals into a composite signal and demodulates the resultant composite signal and a transmitting section which divides a modulated signal into a plurality of transmit signals, then weights the amplitude and phase of each of the transmit signals by amplitude and phase weight values of each of the antenna elements set in the transmitting section and radiates each of the weighted transmit signals from a corresponding respective one of the antenna elements, and a number of terminal stations each of which is adapted to perform radio communications with the base station, the base station comprising:

a desired/undesired wave information input section which stores an arrival direction and received power of a desired wave from each of the terminal stations and an arrival direction and received power of an undesired wave from an undesired wave source; and

weight value rewrite means for recalculating an amplitude and phase weight values of each of the antenna elements to be used in the receiving and transmitting sections based on the information of the desired/undesired wave information input sections and rewriting the amplitude and phase weight values of each of the antenna elements already set in the receiving and transmitting sections with the recalculated weight values.

2. The radio communication system according to claim 1 wherein the base station further comprises:

receiving condition detecting means for detecting a variation in the receiving condition of the receiving section,

wherein when a variation in the receiving condition of the receiving section is detected by the receiving condition detecting means, the weight value rewrite means recalculates amplitude and phase weight values of each of the antenna elements to be used in the receiving and transmitting sections.

3. The radio communication system according to claim 1, wherein radio communications are performed between the base station and each of the terminal stations by a frequency hopping spectrum spreading technique, the receiving condition detecting means includes error rate detecting means for detecting an increase in error rate of a demodulated signal by the receiving section, and the weight value rewrite means recalculates and rewrites the weight values in the receiving and transmitting sections when an increase in error rate is detected by the error rate detecting means.

4. The radio communication system according to claim 1, wherein radio communications are performed between the base station and each of the terminal stations by a direct spread spectrum spreading technique, the receiving condition detecting means includes communication disabled state detecting means for detecting a communications disabled state of the base station, and the weight value rewrite means recalculates and rewrites the weight values in the receiving and transmitting sections when a communications disabled state of the base station is detected by the communications disabled state detecting means.

5. In a radio communication system comprising a base station installed in a store and having an array antenna including a plurality of antenna elements, a receiving section which weights the amplitude and phase of each of received signals from the plurality of antenna elements by amplitude and phase weight values of each of the antenna elements set in the receiving section, then combines the weighted signals into a composite signal and demodulates the resultant composite signal and a transmitting section which divides a modulated signal into a plurality of transmit signals, then weights the amplitude and phase of each of the transmit signals by amplitude and phase weight values of each of the antenna elements set in the transmitting section and radiates each of the weighted transmit signals from a corresponding respective one of the antenna elements, a number of terminal stations each of which is installed in the store, connected to a corresponding one of registration terminals for registering data on sales of goods and adapted to perform radio communications with the base station, and host equipment for collecting the data on sales of goods registered by each of the registration terminals via the base station, the base station comprising:

a desired/undesired wave information input section which stores an arrival direction and received sower of a desired wave from each of the terminal stations and an arrival direction and received power of an undesired wave from an undesired wave source,

weight value rewrite means for recalculating amplitude and phase weight values of each of the antenna elements to be used in the receiving and transmitting sections based on the information of the desired/undesired wave information input section and rewriting the amplitude and phase weight values of each of the antenna elements already set in the receiving and transmitting sections with the recalculated weight values; and

receiving condition detecting means for detecting a variation in the receiving condition of the receiving sections,

wherein when a variation in the receiving condition of the receiving section is detected, the weight value rewrite means recalculates amplitude and phase weight values of each of the antenna elements to be used in the receiving and transmitting sections and rewrites the amplitude and phase weight values of each of the antenna elements already set in the receiving and transmitting sections with the recalculated weight values.

6. The radio communication system according to claim 5, wherein the receiving condition detecting means includes time setting means for setting times of recalculating the weight values and a clock for measuring time, and the weight value rewrite means recalculates and rewrites the weight values in the receiving and transmitting sections when a time of recalculating the weight values set by the time setting means is reached by the time measured by the clock.

7. The radio communication system according to claim 5, wherein radio communications are performed between the base station and each of the terminal stations by a frequency hopping spectrum spreading technique, the receiving condition detecting means includes error rate detecting means for detecting an increase in error rate of a demodulated signal by the receiving section, and the weight value rewrite means recalculates and rewrites the weight values in the receiving and transmitting sections when an increase in error rate is detected by the error rate detecting means.

8. The radio communication system according to claim 5, wherein radio communications are performed between the base station and each of the terminal stations by a direct spread spectrum spreading technique, the receiving condition detecting means includes communication disabled state detecting means for detecting a communications disabled state of the base station, and the weight value rewrite means recalculates and rewrites the weight values in the receiving and transmitting sections when a communications disabled state of the base station is detected by the communications disabled state detecting means.

9. A base station adapted to perform radio communications with a number of terminal stations and having an array antenna including a plurality of antenna elements, a receiving section which weights the amplitude and phase of each of received signals from the plurality of antenna elements by amplitude and phase weight values of each of the antenna elements set in the receiving section, then combines the weighted signals into a composite signal and demodulates the resultant composite signal and a transmitting section which divides a modulated signal into a plurality of transmit signals, then weights the amplitude and phase of each of the transmit signals by amplitude and phase weight values of each of the antenna elements set in the transmitting section and radiates each of the weighted transmit signals from a corresponding respective one of the antenna elements, the base station comprising:

a desired/undesired wave information input section which stores an arrival direction and received power of a desired wave from each of the terminal stations and an arrival direction and received power of an undesired wave from an undesired wave source,

weight value rewrite means for recalculating amplitude and phase weight values of each of the antenna elements to be used in the receiving and transmitting sections based on the information of the desired/undesired wave information input section and rewriting the amplitude and phase weight values of each of the antenna elements already set in the receiving and transmitting sections with the recalculated weight values; and

receiving condition detecting means for detecting a variation in the receiving condition of the receiving sections, wherein when a variation in the receiving condition of the receiving section is detected by the receiving condition detecting means, the weight value rewrite means recalculates amplitude and phase weight values of each of the antenna elements to be used in the receiving and transmitting sections and rewrites the amplitude and phase weight values of each of the antenna elements already set in the receiving and transmitting sections with the recalculated weight values.

10. The base station according to claim 9, wherein radio communications are performed between the base station and each of the terminal stations by a frequency hopping spectrum spreading technique, the receiving condition detecting means includes error rate detecting means for detecting an increase in error rate of a demodulated signal by the receiving section, and the weight value rewrite means recalculates and rewrites the weight values in the receiving and transmitting sections when an increase in error rate is detected by the error rate detecting means.

11. The base station according to claim 9, wherein radio communications are performed between the base station and each of the terminal stations by a direct spread spectrum spreading technique, the receiving condition detecting means includes communication disabled state detecting means for detecting a communications disabled state of the base station, and the weight value rewrite means recalculates and rewrites the weight values in the receiving and transmitting sections when a communications disabled state of the base station is detected by the communications disabled state detecting means.

12. In a radio communication system comprising a base station installed in a store and having an array antenna including a plurality of antenna elements, a receiving section which weights the amplitude and phase of each of received signals from the plurality of antenna elements by amplitude and phase weight values of each of the antenna elements set in the receiving section, then combines the weighted signals into a composite signal and demodulates the resultant composite signal and a transmitting section which divides a modulated signal into a plurality of transmit signals, then weights the amplitude and phase of each of the transmit signals by amplitude and phase weight values of each of the antenna elements set in the transmitting section and radiates each of the weighted transmit signals from a corresponding respective one of the antenna elements, a number of terminal stations each of which is installed in the store, connected to a corresponding one of registration terminals for registering data on sales of goods and adapted to perform radio communications with the base station, and host equipment for collecting the data on sales of goods registered by each of the registration terminals via the base station, the base station comprising:

receiving condition detecting means for detecting a variation in the receiving condition of the receiving section; and

weight value rewrite means for, when a variation in the receiving condition of the receiving section is detected, recalculating amplitude and phase weight values of each of the antenna elements to be used in the receiving and transmitting sections and rewriting the amplitude and phase weight values of each of the antenna elements already set in the receiving and transmitting sections with the recalculated weight values,

wherein the receiving condition detecting means comprises time setting means for setting times of recalculating the weight values and a clock for measuring time, and the weight value rewrite means recalculates and rewrites the weight values in the receiving and transmitting sections when a time of recalculating the weight values set by the time setting means is reached by the time measured by the clock.