Radio communication device and semiconductor integrated circuit device used for the same
View Patent ↗A semiconductor integrated circuit for a radio communication terminal sequentially uses a plurality of frequency channels by instructions from a hopping frequency decision unit to receive packet data by a reception unit. When the integrated circuit cannot detect the head of the packet data in reception operations, the integrated circuit cannot receive packet data should be received originally then assumes that the received packet data is a packet error. And the integrated circuit calculates packet error rates for each frequency channel on the basis of the number of times of reception operations performed for each frequency channel and of the number of times of packet errors to estimate channel qualities by using the packet error rates.
1. A semiconductor integrated circuit device for a radio communication terminal of a frequency hopping system to transmit/receive packet data by sequentially using a plurality of frequency channels, comprising:
a hopping frequency decision unit configured to select a frequency channel from among the plurality of frequency channels as frequency hopping;
a transmission unit configured to assign transmission packet data to the frequency channel selected by the hopping frequency decision unit to transmit the transmission packet data using the frequency channel selected by the hopping frequency decision unit;
a reception unit configured to receive reception packet data using the frequency channel selected by the hopping frequency decision unit; and
a control unit configured to estimate channel qualities of the frequency channels used by the reception unit, and which makes the hopping frequency decision unit perform the frequency hopping,
wherein the control unit is configured to execute control of:
firstly calculating packet error rates of frequency channels of which the channel qualities are assumed to be good and used in reception operations of the reception packet data to estimate channel qualities,
secondly measuring field strengths in idle slots of frequency channels of which the channel qualities are assumed to be bad and not used in the reception operations of the reception packet data to estimate channel qualities,
thirdly determining whether the frequency channels are usable or not on a basis of an estimation result of channel qualities of frequency channels being estimation targets of the channel qualities, and
fourthly avoiding frequency channels determined to be unusable, and
wherein the control unit is configured to refrain from determining whether the channel qualities are good and used if the reception packet data is not detected by the reception unit at a time when the reception unit is expected to receive the reception packet data, and
wherein each of the hopping frequency decision unit, transmission unit, reception unit, and control unit are embodied as a processor and non-transitory processor readable medium storing software or as hardware.
2. A radio communication terminal comprising:
a semiconductor integrated circuit device according to claim 1 ;
a radio antenna connected to the semiconductor integrated circuit device; and
a host connected to the semiconductor integrated circuit device and configured to transmit and receive data and commands to and from the semiconductor integrated circuit device.
3. The device according to claim 1 ,
wherein the reception unit is configured to receive a radio wave of a specified frequency to demodulate the radio wave, search Sync Word of a preset pattern from demodulated data to detect a head of the reception packet data,
wherein the control unit is configured to refrain from determining whether the channel qualities are good and used if a head of the reception packet data is not detected by the reception unit.
4. The device according to claim 3 , wherein the control unit is configured to refrain from determining whether the channel qualities are good and used if searching the Sync Word times out.