Background technology
As everyone knows, in recent years, adopt the mobile radio communicaltions system of CDMA mode to make one notice.This system adopts the communication mode of spread spectrum communication mode as it.
Here, with reference to Fig. 1, the existing mobile radio terminal in the above-mentioned mobile communication system is described.Here especially the receiving system relevant with the present invention is illustrated as the center.
The digital modulation mode of emitter 12 usefulness PSK (phase shift keying) modulation etc. is modulated the emission data of audio communication and data communication etc., with spreading code these modulated data is extended to wide band baseband signal.
Then, emitter 12 is up-converted into radio frequency signals with above-mentioned baseband signal, is input to first antenna 10 by antenna multicoupler 11, by first antenna 10 above-mentioned signal is transmitted in the space then and goes unillustrated base station in figure.
On the other hand, the radio signal in that first antenna 10 receives by above-mentioned base station is input to receiving system 13 by antenna multicoupler 11 with it.Receiving system 13 is by radio circuit 14, and intermediate-frequency circuit 15 and Rake (separating multiple diameter) receiver 16 is formed.
At first, in radio circuit 14, will be input to attenuator 14a from the radio signal that antenna multicoupler 11 receives, at this attenuator 14a, predefined amount only decays.By the signal of attenuator 14a, in amplifier 14b, be amplified to behind the fixed level, in frequency mixer 14c, carry out mixing with the signal that in frequency synthesizer 14d, generates, be downconverted into intermediate-freuqncy signal.
The signal that is downconverted into this intermediate frequency is input to intermediate-frequency circuit 15, in amplifier 15a, be amplified to fixed level.Amplify among the result at this, have only desired frequency band, be input to frequency mixer 15c by band pass filter (BPF) 15b.
At frequency mixer 15c, carry out mixing by the signal of band pass filter 15b and the signal that in frequency synthesizer 15d, generates, be transformed into baseband signal.In A/D (analog/digital) converter (A/D) 15e, this baseband signal is transformed into digital signal, is input to Rake receiver 16.
Rake receiver 16 is by searcher 16a, the 16b of branch, and 16c, 16d and symbol combiner 16e form.Above-mentioned digital signal is input to searcher 16a respectively, the 16b of branch, 16c, 16d.
Searcher 16a, in order to detect the signal that mulitpath is come the terminal of controlling oneself that passes through from above-mentioned base station, carry out so-called multipath detected, use with the identical spreading code that is used to expand in emission side and in all timings, above-mentioned digital signal is carried out contrary expansion.
Then, searcher 16a from above-mentioned contrary spreading result, asks the Ec/Io (Io is the total electrical power spectrum density in the frequency acceptance band, and Ec is the pilot energy of putting aside) of mulitpath during the IPN chip, and asks the delay-time difference (postponing to distribute) of these road warps.Then,, ask the reception timing (contrary expansion regularly) in the path that is suitable for receiving, it is distributed to the 16b of branch, 16c, 16d respectively according to these results.
The 16b of branch, 16c, 16d use with the identical spreading code that is used in emission side expand above-mentioned digital signal are implemented contrary extension process in the contrary expansion regularly that is distributed by searcher 16a.
Symbol combiner 16e considers and distributes to each 16b of branch, 16c, the contrary expansion of 16d regularly, to respectively at the 16b of branch, 16c, the multipath composition of 16d superinverse expansion carries out symbol combination.
In the Signal Processing Element 17 of back, the signal through symbol combination on symbol combiner 16e is carried out the demodulation corresponding with the digital modulation of emission side, receive data thereby produce again.
In addition, on this mobile radio terminal, unillustrated control assembly carries out the control for handover according to the Ec/Io of the pilot signal of trying to achieve among the figure on searcher 16a.
In this control, when in waiting for the accepting state that receives, carrying out receiving intermittence, above-mentioned Ec/Io, if satisfied (1) is lower than setting, relatively be reduced to more than the setting during (2) with last time reception, or the difference of the Ec/Io of (3) and neighbor base station at setting with interior etc. condition, then in order to carry out handover, measure Ec/Io from the pilot signal of other base station.Then, when the Ec/Io of the pilot signal of other base station is bigger than setting, proceed to the handover of other base station.
Then, in addition, when mobile radio terminal is in the state of conversing, the Ec/Io of the pilot signal of the base station that is now just connecting becomes lower than setting, and when the Ec/Io of the pilot signal of neighbor base station becomes bigger than setting, though do not communicate in interior a plurality of base stations, carry out handover with comprising the base station of satisfying institute's fixed condition.
Advantage as above such CDMA mode, we can enumerate (1) so because with spread spectrum remarkable communication security is arranged, (2) so because very high anti-decline is arranged with the Rake receive mode, (3) can carry out not can instantaneous trip communication stable handover, so-called soft handover etc.
; in the mobile radio terminal of existing CDMA mode; because the multipath resolution of searcher 16a is the inverse by spreading rate; promptly determine during PN chip; so in the little situation of the width of time of delay of the multi-path signal that causes by this resolution, can not use the 16b of branch, 16c as described above; 16d separates the multipath composition respectively, carries out symbol combination.
That is, by the 16b of branch, 16c, the multi-path signal (ground wave, first reflected wave, second reflected wave) that 16d receives, the width of time of delay is little, the above delay of spreading rate inverse does not take place and can not carry out Rake to receive.
Like this, because because the delay-time difference between the multi-path signal can not produce the reflected wave more late than ground wave, again so exist anti-decline reduction can not guarantee stable problems such as communication quality.These problems take place in the low speed of walking degree in addition, more significantly when moving with inactive state than high-speed mobile.
In addition, like this, so because time of delay of multi-path signal little can not carrying out in the situation that Rake receives, the decline of generation multipath, although temporarily the frame error from the pilot signal of present base station is carried out institute's fixed number when detecting, the loss of decision-making system, catch from system.
In addition, this is as shown in Figure 2, under the influence that received energy is declined, relies on the place that received energy reduces once in a while and receives.
As mentioned above, judge the loss of system, carry out again when the processing of beginning is caught by system that conversation is interrupted and waited for the outer demonstration of unexpected occurrence scope when receiving when conversing, all needs is time-consuming up to the state that enters the wait reception.All with unnecessarily consuming cells is relevant for these.
Embodiment
Below, with reference to all figure, example of the present invention is described.
Fig. 3 is the figure of expression according to the formation of the mobile radio terminal of the CDMA mode of first example of the present invention.But, in Fig. 3, add that on the parts identical identical symbol represents with Fig. 1 of formation of the mobile radio terminal of the existing CDMA mode of expression, particularly here the receiving system relevant with the present invention described as the center.
The digital modulation mode of emitter 12 usefulness PSK modulation etc. is modulated the emission data of audio communication and data communication etc., with spreading code these modulated data is extended to wide band baseband signal.
Then, emitter 12 is up-converted into radio frequency signals with above-mentioned baseband signal, is input to first antenna 10 by antenna multicoupler 11, by first antenna 10 above-mentioned signal is transmitted in the space then and goes unillustrated base station in figure.
On the other hand, the radio signal with first antenna 10 receives by above-mentioned base station is input to receiving system 13a by antenna multicoupler 11 with it.Receiving system 13a is by adapter 20, radio circuit 14, and intermediate-frequency circuit 15 and Rake (separating multiple diameter) receiver 16 is formed.
At first, adapter 20 will be input to the described control assembly 100 in back from the received signal of antenna multicoupler 11 inputs and the received signal that is limited in by band pass filter (BPF) 19 in the desired frequency band that receives at second antenna 18, carry out switching controls with control assembly 100, and be input to radio circuit 14 one in two above-mentioned received signals.
Second antenna 18 is installed in the casing inside of this mobile radio terminal.
In radio circuit 14, will be input to attenuator 14a from the radio signal that adapter 20 receives, there, predefined amount only decays.By the signal of attenuator 14a, in amplifier 14b, be amplified to behind the fixed level, in frequency mixer 14c, carry out mixing with the oscillation signals according that in frequency synthesizer 14d, generates, be downconverted into intermediate-freuqncy signal.
The signal that is downconverted into this intermediate frequency is input to intermediate-frequency circuit 15, in amplifier 15a, be amplified to fixed level.Amplify among the result at this, have only desired frequency band, be input to frequency mixer 15c by band pass filter (BPF) 15b.
At frequency mixer 15c, carry out mixing by the signal of band pass filter 15b and the signal that in frequency synthesizer 15d, generates, be transformed into baseband signal.This baseband signal is transformed into digital signal in that A/D (analog/digital) converter (A/D) 15e is last, is input to Rake receiver 16.
Rake receiver 16 is by searcher 16a, the 16b of branch, and 16c, 16d and symbol combiner 16e form, and above-mentioned digital signal is input to searcher 16a and the 16b of branch, 16c, 16d respectively.
Searcher 16a, in order to detect the signal that mulitpath is come own terminal that passes through from above-mentioned base station, perhaps carry out so-called multipath detected, use with the identical spreading code that is used to expand in emission side and in all timings, above-mentioned digital signal is carried out contrary expansion.
Then, searcher 16a from above-mentioned contrary spreading result, asks the Ec/Io of mulitpath, and asks the delay-time difference (postponing to distribute) of these road warps.Then,, ask the reception timing (contrary expansion regularly) in the path that is suitable for receiving, it is distributed to the 16b of branch, 16c, 16d respectively according to these results.
The 16b of branch, 16c, 16d use with the identical spreading code that is used in emission side expand above-mentioned digital signal are implemented contrary extension process in the contrary expansion regularly that is distributed by searcher 16a.
Symbol combiner 16e considers and distributes to each 16b of branch, 16c, the contrary expansion of 16d regularly, to respectively at the 16b of branch, 16c, 16d is last to be carried out symbol combination by the contrary multipath composition of expanding.
In the Signal Processing Element 17 of back, the signal synthetic to symbols on symbol combiner 16e carries out the demodulation corresponding with the digital modulation of emission side, receives data thereby produce again.
Control assembly 100 has CPU (CPU (central processing unit)), ROM (read-only memory) and RAM (random access memory) etc., above-mentioned CPU is according to the control program and the control data that are stored among the above-mentioned ROM, each parts of this mobile radio terminal are united control, for example carry out the control relevant with handover.
In addition, in order to realize new controlled function, control assembly 100 has received energy decision maker 100a and adapter switching control 100b.
Received energy decision maker 100a according to respectively at above-mentioned searcher 16a, the 16b of branch, 16c, the Ec/Io of the received signal of trying to achieve among the 16d judges that the Ec/Io of the signal that receives in first antenna 10 and second antenna 18 which is bigger.
Adapter switching control 100b is according to the result of determination of received energy decision maker 100a, adapter 20 is carried out switching controls, the antenna that is used to communicate by letter is controlled to the switching of first antenna 10 from 10 to second antennas 18 of first antenna or from second antenna 18.
In addition, have the power supply unit as the inscape of this device, it has the battery of supply for the electric power that makes above-mentioned each parts work, but in diagram it has been omitted.
Below, the antenna switching controls work of the mobile radio terminal of above-mentioned formation is described.Fig. 4 is the program operation chart that is used to illustrate above-mentioned Control work, when the user implements the exhalation requirement by unillustrated user interface among the figure, reception when receiving from signal of base station continuously by paging channel, begins this Control work from the incoming signal of base station.
At step 4a, when receiving from signal of base station, detect the Ec/Io of pilot channel by paging channel, advance to step 4b.In addition, at this moment,, from first antenna 10 or second antenna 18, select any one antenna, with the received signal of receiving system 13a reception from the antenna of selecting by adapter 20.
At step 4b, received energy decision maker 100a judges whether do not reach pre-set threshold at the detected Ec/Io of step 4a.Here, when the detected Ec/Io of step 4a does not reach above-mentioned threshold value, advance to step 4c, on the other hand, when the detected Ec/Io of step 4a when above-mentioned threshold value is above, advance to step 4g.
At step 4c, adapter switching control 100b carries out switching controls to adapter 20, switch in first antenna 10 or second antenna 18 on the non-selected antenna of step 4a, advance to step 4d.
At step 4d, be used in the antenna that step 4c selects, by paging channel, receive from signal of base station, detect the Ec/Io of pilot channel, advance to step 4e.
At step 4e, relatively detect Ec/Io that obtains and the Ec/Io that obtains in above-mentioned step 4a detection at step 4d.Here,, advance to step 4g, on the other hand, when detect the Ec/Io that obtains at step 4d be not bigger, advance to step 4f when detecting the Ec/Io obtain at step 4d when big.
At step 4f, adapter switching control 100b carries out switching controls to adapter 20, switch in first antenna 10 or second antenna 18 on the selecteed antenna of step 4a, advance to step 4g.
At step 4g, whether exhalation or incoming call are finished when judging this processing beginning.Here, when finishing, finish this processing, on the other hand, when not finishing, advance to step 4a.
Below, the antenna switching controls work during to conversation describes.Fig. 5 is the program operation chart of the antenna switching controls work in when conversation, offer and the base station between communication link begin conversation, when receiving from signal of base station continuously, this Control work is begun by communication channel.
At step 5a, by communication channel, receive continuously from signal of base station, detect the Ec/Io of pilot channel, advance to step 5b.In addition, at this moment,, from first antenna 10 or second antenna 18, select antenna whichsoever, will be used for receiving system 13a from the received signal of the antenna of selecting by adapter 20.
At step 5b, received energy decision maker 100a judges whether do not reach pre-set threshold at the detected Ec/Io of step 5a.Here, when the detected Ec/Io of step 5a does not reach pre-set threshold, advance to step 5c, on the other hand, when the detected Ec/Io of step 5a when above-mentioned threshold value is above, advance to step 5g.
At step 5c, adapter switching control 100b carries out switching controls to adapter 20, switch in first antenna 10 or second antenna 18 on the non-selected antenna of step 5a, advance to step 5d.
At step 5d, be used in the antenna that step 5c selects, by communication channel, receive continuously from signal of base station, detect the Ec/Io of pilot channel, advance to step 5e.
At step 5e, relatively detect Ec/Io that obtains and the Ec/Io that obtains in above-mentioned step 5a detection at step 5d.Here,, advance to step 5g, on the other hand,, advance to step 5f. when detecting the Ec/Io that obtains at step 5d when big when detecting the Ec/Io obtain at step 5d when big
At step 5f, adapter switching control 100b carries out switching controls to adapter 20, switch in first antenna 10 or second antenna 18 on the selecteed antenna of step 5a, advance to step 5g.
At step 5g, whether conversation finishes when judging this processing beginning.Here, when finishing, finish this processing, on the other hand, when not finishing, advance to step 5a.
Below, the antenna switching controls work when receiving incoming call to waiting for describes.Fig. 6 is a program operation chart of waiting for the antenna switching controls work when receiving incoming call.In addition, when waiting for the reception incoming call, receive from signal of base station off and on as illustrated in fig. 7 by paging channel.
The above-mentioned paging channel of the interval reception of Idle shown in Figure 7 (free time), on the other hand, Sleep (sleep) interval is the state of the power-off of receiving system 13a.In addition, the Idle interval is by up to the heat temperature raising of the working stability of the receiving system 13a of energized interval and be used for the reception interval that incoming signal monitors is formed.
At first, at step 6a, judge that present timing is whether during heat temperature raising.Here, when during heat temperature raising, advance to step 6b.On the other hand, when not during heat temperature raising, advance to step 6a once more, wait for the arrival during the heat temperature raising.
At step 6b, adapter switching control 100b carries out switching controls to adapter 20, during heat temperature raising in by first antenna 10, detect the Ec/Io of the pilot channel of paging channel, advance to step 6c.
At step 6c, adapter switching control 100b carries out switching controls to adapter 20, during heat temperature raising in by second antenna 18, detect the Ec/Io of the pilot channel of paging channel, advance to step 6d.
At step 6d, received energy decision maker 100a judge the Ec/Io that obtains from first antenna 10 that detects at step 6b and step 6c detect from the Ec/Io that second antenna 18 obtains, which is bigger.
Here, when the Ec/Io that obtains from first antenna 10 that detects at step 6b is big, advance to step 6e, on the other hand, when the Ec/Io that obtains from second antenna 18 that detects at step 6c is big, advance to step 6f.
At step 6e, adapter switching control 100b carries out switching controls to adapter 20, communicates at reception interval, but receives by first antenna 10, advances to step 6g.
At step 6f, adapter switching control 100b carries out switching controls to adapter 20, communicates at reception interval, but receives by second antenna 18, advances to step 6g.
At step 6g, judge the exhalation requirement that whether does not have from the user, perhaps not at the incoming signal that receives from the base station.Here,, perhaps when the incoming signal that receives from the base station, finish this processing, on the other hand, when not from user's exhalation requirement, perhaps not when the incoming signal that receives from the base station, advance to step 6a as exhalation requirement from the user.
As implied above, in the mobile radio terminal of above-mentioned formation, during the exhalation incoming call, perhaps when conversation, when the Ec/Io of the received signal by selecteed antenna is lower than predefined level, an antenna by remainder temporarily receives and detects Ec/Io, after this, will receive with the good antenna of Ec/Io.
That is, during the exhalation incoming call, perhaps when conversation, even if Ec/Io, will receive with the good antenna of Ec/Io when worry can not be guaranteed stable communication quality because the multipath decline temporarily reduces.
Because the reflected wave more late than ground wave can not be deferred to more than certain setting (inverse of spreading rate), receive in the time of to produce again so can not carry out Rake, Ec/Io is reduced owing to above-mentioned reflected wave with from other signal of base station formation interference wave.
For this reason, as mentioned above, when the Ec/Io reduction, when worry can not be guaranteed stable communication quality, by receiving, improved the possibility that to catch the reflected wave that the delay more than the above-mentioned setting is arranged from ground wave with good (for example directionality the is different) antenna of Ec/Io.
Therefore, if with the mobile radio terminal of above-mentioned formation, then when the exhalation incoming call, perhaps when conversing, even if under the electric wave environment that fierce decline takes place, also can guarantee stable communication quality.
In addition, in the mobile radio terminal of above-mentioned formation, when waiting for the reception incoming call, establish the reception in reception interval earlier, in during heat temperature raising, detect and switch two each Ec/Io that antenna receives, after this, in reception interval, will receive with the good antenna of Ec/Io.
Therefore, if with the mobile radio terminal of above-mentioned formation, then when waiting for when receiving incoming call, even if under the electric wave environment that fierce decline takes place, also can guarantee stable communication quality.
In addition, the present invention is not limited in the above-mentioned example, for example, in above-mentioned example, during the exhalation incoming call, perhaps in when conversation, when the Ec/Io of the received signal by selecteed antenna was lower than predefined level, an antenna by remainder temporarily received and detects Ec/Io.
Replace this, when handoff condition is set up and base station can not catch the time, or frame error is continuous when fixing a number, an antenna by remainder temporarily receives and detects Ec/Io, after this, even if receive, also can obtain same effect with the good antenna of Ec/Io.
Below, the mobile radio terminal according to the CDMA mode of second example of the present invention is described.Fig. 8 is the figure of its formation of expression.But, in Fig. 8, add that on the parts identical identical symbol represents with Fig. 1 of formation of the mobile radio terminal of the existing CDMA mode of expression, especially here, the receiving system relevant with the present invention described as the center.
The digital modulation mode of emitter 12 usefulness PSK modulation etc. is modulated the emission data of audio communication and data communication etc., with spreading code these modulated data is extended to wide band baseband signal.
Then, emitter 12 is up-converted into radio frequency signals with above-mentioned baseband signal, is input to first antenna 10 by antenna multicoupler 11, by first antenna 10 above-mentioned signal is transmitted in the space then and goes unillustrated base station in figure.
On the other hand, the radio signal in that first antenna 10 receives by above-mentioned base station is input to receiving system 13b by antenna multicoupler 11 with it.Receiving system 13b is by adapter 20, radio circuit 14, and intermediate-frequency circuit 15 and Rake (separating multiple diameter) receiver 16 is formed.
At first, adapter 20 inputs are from the received signal of antenna multicoupler 11 inputs and the received signal that is limited in the desired frequency band by band pass filter (BPF) 19 that receives at second antenna 18, carry out switching controls with the described control assembly 101 in back, be input to radio circuit 14 one in two above-mentioned received signals.
Second antenna 18 is installed in the casing inside of this mobile radio terminal.
In radio circuit 14, will be from the radio signal input attenuator 14a of adapter 20 receptions, there, predefined amount only decays.By the signal of attenuator 14a, in amplifier 14b, be amplified to behind the fixed level, in frequency mixer 14c, mix with the oscillation signals according that in frequency synthesizer 14d, generates, be downconverted into intermediate frequency.
The signal that is downconverted into this intermediate frequency is input to intermediate-frequency circuit 15, in amplifier 15a, be amplified to fixed level.In this result amplified, have only desired frequency band by band pass filter (BPF) 15b, be input to frequency mixer 15c.
At frequency mixer 15c, mix by the signal of band pass filter 15b and the signal that in frequency synthesizer 15d, generates, be transformed into baseband signal.This baseband signal is transformed into digital signal in that A/D (analog/digital) converter (A/D) 15e is last, is input to Rake receiver 16.
Rake receiver 16 is by searcher 16a, the 16b of branch, and 16c, 16d and symbol combiner 16e form, and above-mentioned digital signal are input to searcher 16a respectively, the 16b of branch, 16c, 16d.
Searcher 16a, in order to detect the signal that mulitpath is come the terminal of controlling oneself that passes through from above-mentioned base station, perhaps carry out so-called multipath detected, use with the identical spreading code that is used to expand in emission side and in all timings, above-mentioned digital signal is carried out contrary expansion.
Then, searcher 16a from above-mentioned contrary spreading result, asks the Ec/Io of mulitpath, and asks the delay-time difference (delayed profile) of these road warps.Then,, ask the reception timing (contrary expansion regularly) in the path that is suitable for receiving, it is distributed to the 16b of branch, 16c, 16d respectively according to these results.
The 16b of branch, 16c, 16d use with the identical spreading code that is used in emission side expand above-mentioned digital signal are implemented contrary extension process in the contrary expansion regularly that is distributed by searcher 16a.
Symbol combiner 16e considers and distributes to each 16b of branch, 16c, the contrary expansion of 16d regularly, to respectively at the 16b of branch, 16c, the multipath composition of 16d superinverse expansion carries out symbol combination.
In the Signal Processing Element 17 of back, the signal synthetic to symbols on symbol combiner 16e carries out the demodulation corresponding with the digital modulation of emission side, receives data thereby produce again.
Control assembly 101 has CPU, ROM and RAM etc., and above-mentioned CPU basis is stored in control program and the control data of above-mentioned ROM, each parts of this mobile radio terminal is united control, and for example carries out the control relevant with handover.
In addition, in order to realize new controlled function, control assembly 101 has frame error decision maker 101a and adapter switching control 101b.
Frame error decision maker 101a judges about above-mentioned reception data with being included in the CRC spreading rate in the demodulated received data in the Signal Processing Element 17, frame error whether not more than the fixed frame number continuously.
Adapter switching control 101b is according to the result of determination of above-mentioned frame error decision maker 101a, adapter 20 is carried out switching controls, the antenna that is used to communicate by letter is controlled to the switching of first antenna 10 from 10 to second antennas 18 of first antenna or from second antenna 18.
In addition, have the power supply unit as the inscape of this device, it has the battery of supply for the electric power that makes above-mentioned each parts work, but in diagram it has been omitted.
Below, the antenna switching controls work of the mobile radio terminal of above-mentioned formation is described.This Control work is to implement by above-mentioned control assembly 101.
At first, to when breathing out, or the antenna switching controls work when incoming call describes.Fig. 9 is the program operation chart that is used to illustrate above-mentioned Control work, and the user implements the exhalation requirement by unillustrated user interface among the figure, receives the incoming signal from the base station, when receiving from signal of base station by paging channel, this Control work is begun.
At step 9a, paging channel is scanned, determine the base station, advance to step 9b.
At step 9b, receive from signal of base station by paging channel, advance to step 9c.In addition, at this moment,, from first antenna 10 or second antenna 18, select antenna whichsoever, will be used for receiving system 13a from the received signal of selecteed antenna by adapter 20.
At step 9c, frame error decision maker 101a judges about above-mentioned reception data with being included in the CRC spreading rate in the demodulated received data in the Signal Processing Element 17, frame error whether not more than the fixed frame number continuously.
Here, when frame error the fixed above consecutive hours of frame number, advance to step 9d, on the other hand, when frame error not the fixed above consecutive hours of frame number, advance to step 9a.
At step 9d, adapter switching control 101b carries out switching controls to adapter 20, to the antenna that is used to communicate by letter from the antenna that now using to not controlling in the switching of the antenna that uses, advance to step 9e.
At step 9e, carry out CRC spreading rate in the reception data that demodulation obtains with being included in 17 pairs of Signal Processing Elements by the received signal of the antenna that switched at step 9d, frame error decision maker 101a judges about above-mentioned reception data, frame error whether not more than the fixed frame number continuously.
Here, when frame error the fixed above consecutive hours of frame number, advance to step 9a, on the other hand, when frame error not the fixed above consecutive hours of frame number, advance to step 9f.
At step 9f, whether exhalation or incoming call are finished when judging this processing beginning.Here, when finishing, finish this processing, on the other hand, when not finishing, advance to step 9a.
Below, the antenna switching controls work during to conversation describes.Figure 10 is the program operation chart of the antenna switching controls work in when conversation, by offer and the base station between communication link begin conversation, when receiving from signal of base station continuously, this Control work is begun by communication channel.
At step 10a, by communication channel, receive continuously from signal of base station, advance to step 10b.In addition, at this moment,, from first antenna 10 or second antenna 18, select any one antenna, will be used for receiving system 13a from the received signal of selecteed antenna by adapter 20.
At step 10b, frame error decision maker 101a with being included in CRC spreading rate in the reception data that demodulation obtains in the Signal Processing Element 17, judges about above-mentioned reception data, frame error whether not more than the fixed frame number continuously.
Here, when frame error the fixed above consecutive hours of frame number, advance to step 10c, on the other hand, when frame error not the fixed above consecutive hours of frame number, advance to step 10a.
At step 10c, adapter switching control 101b carries out switching controls to adapter 20, to the antenna that is used to communicate by letter from the antenna that now using to not controlling in the switching of the antenna that uses, advance to step 10d.
At step 10d, carry out CRC spreading rate in the reception data that demodulation obtains with being included in 17 pairs of Signal Processing Elements by the received signal of the antenna that switches at step 10c, frame error decision maker 101a judges about above-mentioned reception data, frame error whether not more than the fixed frame number continuously.
Here, when frame error the fixed above consecutive hours of frame number, advance to step 10f, on the other hand, when frame error not the fixed above consecutive hours of frame number, advance to step 10e.
At step 10e, whether conversation finishes when judging this processing beginning.Here, when finishing, finish this processing, on the other hand, when not finishing, advance to step 10a.
At step 10f, implement to finish the processing of conversation, finish this processing.
As implied above, in the mobile radio terminal of above-mentioned formation, have two antennas 10,18, paging channel when being received in the exhalation incoming call with selecteed antenna respectively and the communication channel when conversation.Then, as shown in figure 11, when the frame error of this received signal (in the example at Figure 11 two more than the frame) consecutive hours more than the fixed number, the antenna that uses is received from the antenna that the antenna that is now using switches to other.
That is, during the exhalation incoming call, perhaps in when conversation because the multipath decline, even if temporarily frame error continuously fix a number more than, in the time of can not guaranteeing stable communication quality, will receive with other antenna.
Therefore, exist because receive the variation that the position of RF signal has only distance between two antennas from the space, so as shown in figure 12, this position receives variation regularly before and after enoughly switching by antenna, switches to the possibility that another antenna behind the very little RF signal of influence of fading receives.
So, if, then when the exhalation incoming call, perhaps when conversation,, can prevent system loss even if under the electric wave environment that fierce decline takes place, can improve the possibility of guaranteeing stable communication quality with the mobile radio terminal of above-mentioned formation.
Like this, by preventing system loss, can prevent to converse when conversing and interrupt, required battery waste is caught by demonstration when waiting for reception outside the occurrence scope and system.
In addition, the present invention is not limited in the above-mentioned example, for example, in above-mentioned example, when frame error at the above consecutive hours of fix a number, receive by an antenna of remainder, replace this situation, when frame error at the above consecutive hours of fix time, even if receive, also can obtain same effect by an antenna of remainder.
In addition, in the scope that does not break away from main idea of the present invention, even if apply all variations, it is self-evident also can similarly implementing the present invention.