Receiver of carrier sense multiplexing connection method and interference suppressing method thereof
First Claim
1. An interference suppression method for a receiver in a packet radio communication system using the carrier sense multiple access method, comprising the sequential steps of:
- filtering a received signal by narrowband filtering;
at a received signal strength indicator, detecting an electric field strength of the received signal;
at a carrier sense judgment device, receiving an output from the received signal strength indicator indicating the electric field strength of the received signal;
at the carrier sense judgment device, determining, based on the output from the received signal strength indicator, whether the received signal is a carrier; and
upon a determination at the carrier sense judgment device that the received signal is a carrier, changing the filtering of the received signal from narrowband filtering to wideband filtering without being subjected to the narrowband filtering, and causing a demodulator to begin demodulating the received signal filtered by wideband filtering; and
wherein the filtering, in a first mode having the narrowband characteristic, is configured with a passband that is narrower than a one-channel modulation occupied bandwidth and the filtering, in a second mode having the wideband characteristic, is configured with a passband equal to or wider than the one-channel modulation occupied bandwidth.
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Accused Products
Abstract
A broad band packet radio communication system is characterized by the carrier sense multiplexing connection method operated on a harsh frequency arrangement where an occupied band width of a modulation transmission/reception wave and a modulation side lobe are wide and the frequency channel interval is narrow. It is possible to improve the reception adjacent channel interference characteristic among a plurality of terminals belonging to the respective cells existing in the vicinity of adjacent frequency cell boundary area. The RSSI system is subjected to a narrow-band channel filtering (a narrow-band filter (BPF or LPF) having a band narrower than one-channel occupied band width) while the reception/demodulation system is subjected to a wide-band channel filtering (a wide-band filter (BPF or LPF) having a pass band equal to or wider than the one-channel occupied band width).
38 Citations
19 Claims
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1. An interference suppression method for a receiver in a packet radio communication system using the carrier sense multiple access method, comprising the sequential steps of:
- filtering a received signal by narrowband filtering;
at a received signal strength indicator, detecting an electric field strength of the received signal;
at a carrier sense judgment device, receiving an output from the received signal strength indicator indicating the electric field strength of the received signal;
at the carrier sense judgment device, determining, based on the output from the received signal strength indicator, whether the received signal is a carrier; and
upon a determination at the carrier sense judgment device that the received signal is a carrier, changing the filtering of the received signal from narrowband filtering to wideband filtering without being subjected to the narrowband filtering, and causing a demodulator to begin demodulating the received signal filtered by wideband filtering; and
wherein the filtering, in a first mode having the narrowband characteristic, is configured with a passband that is narrower than a one-channel modulation occupied bandwidth and the filtering, in a second mode having the wideband characteristic, is configured with a passband equal to or wider than the one-channel modulation occupied bandwidth. - View Dependent Claims (2, 3, 4)
- filtering a received signal by narrowband filtering;
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5. An interference suppression method for a superheterodyne receiver in a packet radio communication system using the carrier sense multiple access method, comprising the steps of:
- filtering a received signal through a bandpass filter configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to intermediate frequency;
receiving, at a received signal strength indicator, the narrowband filtered signal, the received signal strength indicator generating an RSSI output that indicates an electric field strength of the narrowband filtered signal; and
at a carrier sense judgment device, receiving the RSSI output and generating a carrier sense judgment based on a detected strength of the narrowband filtered signal as indicated by the RSSI output, and in the case where the received signal is regarded as a carrier, based on the carrier sense judgment, causing a demodulator to demodulate the received signal whose frequency has been converted to the intermediate frequency and filtered by the bandpass filter reconfigured with a wideband characteristic, wherein the wideband characteristic is wider than the narrowband characteristic; and
wherein the bandpass filter, in a first mode having the narrowband characteristic, is configured with a passband that is narrower than a one-channel modulation occupied bandwidth and the bandpass filter, in a second mode having the wideband characteristic, is configured with a passband equal to or wider than the one-channel modulation occupied bandwidth. - View Dependent Claims (6)
- filtering a received signal through a bandpass filter configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to intermediate frequency;
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7. An interference suppression method for a superheterodyne receiver in a packet radio communication system using the carrier sense multiple access method, comprising the steps of:
- filtering a received signal through a bandpass filter configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to a baseband frequency;
receiving, at a received signal strength indicator, the narrowband filtered signal, the received signal strength indicator generating an RSSI output that indicates an electric field strength of the narrowband filtered signal;
at a carrier sense judgment device, receiving the RSSI output and generating a carrier sense judgment based on a detected strength of the narrowband filtered signal as indicated by the RSSI output; and
at the carrier sense judgment device, upon a determination that the received signal is a carrier based on the carrier sense judgment, causing the bandpass filter to be reconfigured to operate with a wideband characteristic and causing a demodulator to demodulate the received signal whose frequency has been converted to the baseband frequency and filtered by the bandpass filter reconfigured with the wideband characteristic, wherein the wideband characteristic is wider than the narrowband characteristic;
wherein the bandpass filter, in a first mode having the narrowband characteristic, is configured with a passband that is narrower than a one-channel modulation occupied bandwidth and the bandpass filter, in a second mode having the wideband characteristic, is configured with a passband equal to or wider than the one-channel modulation occupied bandwidth. - View Dependent Claims (8, 9, 10)
- filtering a received signal through a bandpass filter configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to a baseband frequency;
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11. An interference suppression method for a direct conversion receiver in a packet radio communication system using the carrier sense multiple access method, comprising the steps of:
- filtering a received signal through a bandpass filter configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to a baseband frequency;
receiving, at a received signal strength indicator, the narrowband filtered signal, the received signal strength indicator generating an RSSI output that indicates an electric field strength of the narrowband filtered signal; and
at a carrier sense judgment device, receiving the RSSI output and generating a carrier sense judgment based on a detected strength of the narrowband filtered signal as indicated by the RSSI output, and in the case where the received signal is regarded as a carrier, based on the carrier sense judgment, causing a demodulator to demodulate the received signal whose frequency has been converted to the baseband frequency and filtered by the bandpass filter reconfigured with a wideband characteristic, wherein the wideband characteristic is wider than the narrowband characteristic;
wherein the bandpass filter, in a first mode having the narrowband characteristic, is configured with a passband that is narrower than a one-channel modulation occupied bandwidth and the bandpass filter, in a second mode having the wideband characteristic, is configured with a passband equal to or wider than the one-channel modulation occupied bandwidth. - View Dependent Claims (12)
- filtering a received signal through a bandpass filter configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to a baseband frequency;
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13. An interference suppression method for a superheterodyne receiver in a packet radio communication system using the carrier sense multiple access method, comprising the steps of:
- filtering a received signal through two bandpass filters each configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to intermediate frequency;
receiving, at a received signal strength indicator, the narrowband filtered signal from both bandpass filters, the received signal strength indicator generating an RSSI output that indicates an electric field strength of the narrowband filtered signal; and
at a carrier sense judgment device, receiving the RSSI output and generating a carrier sense judgment based on a detected strength of the narrowband filtered signal as indicated by the RSSI output, and in the case where the received signal is regarded as a carrier, based on the carrier sense judgment, causing a demodulator to demodulate the received signal whose frequency has been converted to the intermediate frequency and filtered by the two bandpass filters reconfigured by the carrier sense judgment device to have a wideband characteristic, wherein the wideband characteristic is wider than the narrowband characteristic;
wherein the two bandpass filters, in a first mode having the narrowband characteristic, are configured with a passband that is narrower than a one-channel modulation occupied bandwidth and the two bandpass filters, in a second mode having the wideband characteristic, are configured with a passband equal to or wider than the one-channel modulation occupied bandwidth. - View Dependent Claims (14)
- filtering a received signal through two bandpass filters each configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to intermediate frequency;
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15. An interference suppression method for a superheterodyne receiver in a packet radio communication system using the carrier sense multiple access method, comprising the steps of:
- filtering a received signal through two bandpass filters each configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to baseband frequency;
receiving, at a received signal strength indicator, the narrowband filtered signal from both bandpass filters, the received signal strength indicator generating an RSSI output that indicates an electric field strength of the narrowband filtered signal; and
at a carrier sense judgment device, receiving the RSSI output and generating a carrier sense judgment based on a detected strength of the narrowband filtered signal as indicated by the RSSI output, and in the case where the received signal is regarded as a carrier, based on the carrier sense judgment, causing a demodulator to demodulate the received signal whose frequency has been converted to the baseband frequency and filtered by the two bandpass filters reconfigured by the carrier sense judgment device to have a wideband characteristic, wherein the wideband characteristic is wider than the narrowband characteristic;
wherein the two bandpass filters, in a first mode having the narrowband characteristic, are configured with a passband that is narrower than a one-channel modulation occupied bandwidth and the two bandpass filters, in a second mode having the wideband characteristic, are configured with a passband equal to or wider than the one-channel modulation occupied bandwidth. - View Dependent Claims (16, 17)
- filtering a received signal through two bandpass filters each configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to baseband frequency;
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18. An interference suppression method for a direct conversion receiver in a packet radio communication system using the carrier sense multiple access method, comprising the steps of:
- filtering a received signal through two bandpass filters each configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to baseband frequency;
receiving, at a received signal strength indicator, the narrowband filtered signal from both bandpass filters, the received signal strength indicator generating an RSSI output that indicates an electric field strength of the narrowband filtered signal; and
at a carrier sense judgment device, receiving the RSSI output and generating a carrier sense judgment based on a detected strength of the narrowband filtered signal as indicated by the RSSI output, and in the case where the received signal is regarded as a carrier, based on the carrier sense judgment, causing a demodulator to demodulate the received signal whose frequency has been converted to the baseband frequency and filtered by the two bandpass filters reconfigured by the carrier sense judgment device to have a wideband characteristic, wherein the wideband characteristic is wider than the narrowband characteristic;
wherein the two bandpass filters, in a first mode having the narrowband characteristic, are configured with a passband that is narrower than a one-channel modulation occupied bandwidth and the two bandpass filters, in a second mode having the wideband characteristic, are configured with a passband equal to or wider than the one-channel modulation occupied bandwidth. - View Dependent Claims (19)
- filtering a received signal through two bandpass filters each configured with a narrowband characteristic to produce a narrowband filtered signal, the received signal having undergone frequency conversion from radio to baseband frequency;
Specification