JP3991909B2 - Wireless communication device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wireless communication device such as a mobile phone, and more particularly to a wireless communication device configured to control transmission power of data transmitted via an antenna.
[0002]
[Prior art]
In the conventional wireless communication apparatus, the adder / subtracter adds / subtracts the band limiting data output from the band limiting ROM and the ramp data output from the lamp ROM at a predetermined timing, thereby eliminating the multiplier. However, it is possible to form a ramp portion that gently changes before and after the burst data (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
JP-A-9-224061 (stage 0014 to stage 0025, FIG. 1)
[0004]
[Problems to be solved by the invention]
In the conventional wireless communication device, the transmission power is always controlled to a constant value except for the ramp parts before and after the transmission data. Therefore, when the reception electric field level of the other station is low, the transmission data is synchronized. The bit cannot be accurately identified from the received data, and the establishment of synchronization at the partner station becomes unstable.
[0005]
The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a wireless communication apparatus capable of stably establishing synchronization and improving communication quality. is there.
[0006]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a radio communication device including a waveform generation unit that converts transmission data into a baseband signal, an orthogonal modulation unit that modulates the baseband signal converted by the waveform generation unit, and the orthogonal modulation unit. A transmission corresponding to a bit position for synchronization in transmission data, comprising: a power amplification unit that amplifies the modulated modulated wave into a transmission wave transmitted from the antenna; and a control unit that controls transmission power of the transmission wave. The transmission power of the wave portion is made larger in a ramp shape than the predetermined transmission power in the other transmission wave portions.
[0007]
According to a second aspect of the present invention, there is provided a radio communication device comprising: a waveform generation unit that converts transmission data into a baseband signal; an orthogonal modulation unit that modulates a baseband signal converted by the waveform generation unit; A power amplifying unit that amplifies the modulated wave modulated by the unit into a transmission wave transmitted from the antenna, and a control unit that maintains constant transmission power during a burst period for transmitting the transmission data, The transmission power at the position corresponding to the bit for synchronization is increased in a ramp shape from the constant transmission power.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
In Embodiment 1, a two-stage ramp process of transmission power according to the reception level when the TDMA system is used as the mobile communication system will be described.
[0009]
The mobile communication system includes a plurality of base stations and a plurality of wireless communication devices that transmit and receive radio waves to and from each base station. In the TDMA system, radio waves of a certain frequency are time-divided, and a plurality of wireless communication apparatuses establish synchronization with each of the time-divided slots, and transmit and receive signals to and from the base station at a predetermined timing. A plurality of wireless communication devices can use the channel.
[0010]
First, FIG. 1 is a block diagram showing a configuration of a wireless communication apparatus according to the present invention. In the figure, audio input from a microphone 1 is converted into a digital signal by an audio CODEC (Compression / DECompression) 2 and input to a TDMA (Time Division Multiple Access) circuit 3. The TDMA circuit 3 converts the input digital signal into a frame to generate transmission data, and inputs the transmission data to the waveform generation unit 4. The waveform generation unit 4 generates two sets of baseband modulation signals of an in-phase signal (hereinafter referred to as Ich) and a quadrature signal (hereinafter referred to as Qch) from the input transmission data, and a quadrature modulator Enter 5. The quadrature modulator 5 modulates a carrier wave generated by a PLL (Phase Locked Loop) 6 based on the input baseband modulation signal. The modulated wave modulated by the quadrature modulator 5 is amplified by the power amplifier 7 and transmitted from the antenna 9 to the base station (not shown) via the duplexer 8.
Next, the received signal received from the base station is received by the antenna 9 and input to the receiver 10 via the duplexer 8. The received signal input to the receiver 10 is converted into an intermediate frequency band using a local frequency generated by the PLL 6. The received signal converted to the intermediate frequency band is input to the demodulator 11, which performs demodulation control of the received signal, generates a received baseband signal, and inputs it to the TDMA circuit 3. The TDMA circuit 3 establishes frame synchronization from the generated received baseband signal, and the voice CODEC 2 reproduces the received baseband signal to the original voice and outputs it from the speaker 12.
The transmission / reception control and the display operation unit 13 are controlled by a control unit 14 equipped with a CPU (Central Processing Unit).
[0011]
Next, FIG. 2 is a diagram illustrating an example of a time slot configuration when the PDC method (Personal Digital Cellular telecommunication system) is used as the TDMA method. In the figure, RX is a reception slot, TX is a transmission slot, and # 0 to 2 are slot numbers used by the wireless communication apparatuses A to C. The transmission timing of the base station in the transmission slot TX # 2 is the reception timing of the reception slot RX of the wireless communication apparatus C, and the transmission timing of the wireless communication apparatus C in the transmission slot TX of the reception slot RX # 2 of the base station. Reception timing. Similarly, TX # 0 and RX # 0 of the base station are used by another radio communication apparatus A, and TX # 1 and RX # 1 are used by another radio communication apparatus B (not shown) for transmission / reception.
[0012]
FIG. 3 is a diagram showing a transmission slot configuration for transmitting data from a PDC wireless communication apparatus to a base station. The wireless communication device C transmits 280 bits of information to RX # 2 of the base station reception channel. Ramp bit (hereinafter R) used as burst transient response guard time, preamble for synchronization (hereinafter P), information channel for transferring voice (hereinafter TCH) / temporarily TCH in time series order High-speed associated channel (hereinafter referred to as FACCH) that performs high-speed data transfer by stealing, synchronization word (hereinafter referred to as SW) that synchronizes with the base station, color code for identifying the base station code and preventing interference with other base stations (Hereinafter referred to as CC), steal flag (hereinafter referred to as SF) for identifying TCH and FACCH, low-speed associated channel (hereinafter referred to as SACCH), TCH / FACCH, and guard bits for ramp-down (hereinafter referred to as G). In these transmission slots, important information for the base station to establish synchronization is SW, CC, SF, and SACCH, and among them, SW and CC are particularly important.
[0013]
Now, if the transmission power at which the wireless communication apparatus transmits transmission data is too large, the transmission power is standardized because it becomes an interference wave to the adjacent channel. In addition, the rise and fall time of the transmission output of the wireless communication device may cause the TCH to be missed or affect the adjacent channel if the time is long, and if the time is short, the leakage power to the adjacent channel increases and The rise and fall times of the transmission output of the wireless communication apparatus are also standardized because this is a cause of interference with the channel. That is, the wireless communication apparatus must make a transient response to the start and end of transmission in accordance with the mobile station burst transmission transient response characteristic standard, and perform transmission within the range from the upper limit to the lower limit of the instantaneous power during the transmission burst stabilization period.
[0014]
FIG. 4 is a diagram showing the ramp processing at the time of transmission burst according to the present invention. (1) and (3) are ramped up to a predetermined transmission power in the 4-bit period of R, and the transmission is turned off in the first 4-bit period of G. Ramp down to the state. (2) and (4) are ramped up to a predetermined transmission power in the last 2 bit period of the first TCH, and a predetermined transmission power in the 1 bit of SF and the first 1 bit period of SACCH, or the first 2 bit period of the second TCH. The ramp is down. In all of (1) to (4), the transmission power is within the standard range.
[0015]
FIG. 5 is a flowchart showing the operation of the two-stage ramp process according to the first embodiment.
First, when the receiver 10 detects reception of a received signal from the base station, ST5-1 measures the reception level of the received signal ST5-2.
The control unit 14 determines whether or not the transmission process is executed in ST5-3. If it is determined that the transmission process is not started in this determination, the control unit 14 returns to ST5-1.
[0016]
If it is determined in ST5-3 that the transmission process is started, ST5-4 compares the reception level measured in ST5-2 with the predetermined value A.
As a result of the comparison, if the reception level is greater than the predetermined value A, the reception level on the base station side can be assumed to be a super-strong electric field level, so that it is determined that communication quality can be ensured even with a small transmission power. A power save ramp process is instructed to the waveform generator 4 via the circuit 3. The waveform generation unit 4 multiplies Ich and Qch generated in the transmission burst transmission start timing, that is, the Rch 4-bit section, by power save ramp-up data, and the Ich and Qch subjected to the power save ramp-up process are quadrature modulators. 5 is ramped up to the transmission power saved in R as shown in FIG. 4 (3). Thereafter, the transmission signal is transmitted while maintaining a constant transmission power, and the waveform generation unit 4 multiplies the data for power save ramp down by the transmission end timing, that is, the first 4 bit section of G, and performs the power save ramp down process. By inputting Ich and Qch to the quadrature modulator 5, as shown in FIG. 4 (3), the signal is ramped down at G and the transmission power is lowered to the transmission off state, and the process ends in ST5-5. As a result, since the transmission power is saved at the time of an ultra-high electric field level, the power consumption can be reduced.
[0017]
Next, when the reception level is less than the predetermined value A in the comparison result of ST5-4, next, the measured reception level is compared with the predetermined value B ST5-6.
As a result of the comparison, when the reception level is larger than the predetermined value B, the reception level on the base station side can be assumed to be a slightly strong electric field level, so it is determined that the call quality can be secured even with a small transmission power. A two-stage power save ramp process is instructed to the waveform generator 4 via the TDMA circuit 3. The waveform generation unit 4 multiplies the Ich and Qch generated in the 4-bit section of R by the data for power save ramp-up, and inputs the Ich and Qch subjected to the power save ramp-up process to the quadrature modulator 5. As shown in 4 (3), the power is ramped up to the transmission power saved at R. After that, after the first TCH is transmitted with the transmission power saved, the waveform generation unit 4 uses the two-stage ramp to the power save ramp-up data at the timing immediately before the establishment of synchronization, that is, the last 2 bits of the first TCH. The data obtained by adding up data is multiplied by the Ich and Qch generation waveforms, and the Ich and Qch subjected to the two-stage ramp-up process are input to the quadrature modulator 5, so that the TCH of the first TCH as shown in FIG. After ramping up to a predetermined transmission power at the end, synchronization is established. Then, the waveform generation unit 4 multiplies the Ich and Qch generation waveform by the data obtained by adding the two-stage ramp-down data to the power save ramp-down data in the first 2-bit section of the SF or TCH, and performs the two-stage ramp-down Ich And Qch are input to the quadrature modulator 5 to ramp down to the transmission power saved in the first 2-bit section of the SF or the second TCH as shown in FIG. 4 (2) or (2 ′). Thereafter, the second TCH is transmitted with the transmission power saved, and the power save ramp-down data is multiplied in the first 4-bit section of G, and the Ich and Qch subjected to the power save ramp-down process are input to the quadrature modulator 5. Then, as shown in FIG. 4 (3), the ramp-down is performed at G, the transmission power is lowered to the transmission off state, and the process ends in ST5-7. As a result, the SW, CC for synchronization and the transmission power for transmitting SF and SACCH in addition to these are ramped up to a predetermined level at a slightly strong electric field level, so that synchronization establishment at the base station is stable. In addition, power consumption can be reduced by power saving while ensuring communication quality.
[0018]
Next, when the reception level is less than the predetermined value B in the comparison result of ST5-6, next, the measured reception level is compared with the predetermined value C ST5-8.
As a result of the comparison, if the reception level is greater than the predetermined value C, it is determined that there is a possibility that stable communication quality cannot be secured with a small transmission power, and transmission processing is performed with the predetermined transmission power. That is, the control unit 14 instructs the waveform generation unit 4 to perform normal ramp processing via the TDMA circuit 3. The waveform generation unit 4 multiplies Ich and Qch generated in the 4-bit section of R by normal ramp-up data, and inputs the Ich and Qch subjected to the normal ramp-up process to the quadrature modulator 5 as shown in FIG. As in 1), R is ramped up to a predetermined transmission power. Thereafter, a transmission signal is transmitted while maintaining a constant transmission power, and the waveform generator 4 multiplies the normal ramp-down data in the first 4-bit section of G, and quadrature modulators the Ich and Qch subjected to the normal ramp-down process 5, as shown in FIG. 4 (1), the power is ramped down at G to reduce the transmission power to the transmission off state, and the process ends in ST 5-9.
[0019]
If the reception level is less than the predetermined value C in the comparison result of ST5-8, it is determined that there is a possibility that stable communication quality cannot be secured with normal transmission power due to the weak electric field. 3 is used to instruct the waveform generation unit 4 to perform a two-step normal ramp process. The waveform generation unit 4 multiplies Ich and Qch generated in the 4-bit section of R by normal ramp-up data, and inputs the Ich and Qch subjected to the normal ramp-up process to the quadrature modulator 5 as shown in FIG. As in 1), R is ramped up to a predetermined transmission power. After that, after the first TCH is transmitted with the normal transmission power, the waveform generation unit 4 generates Ich and Qch data obtained by adding the two-stage ramp-up data to the normal ramp-up data in the last 2-bit section of the TCH. By multiplying the waveform and inputting the Ich and Qch subjected to the two-stage ramp-up process to the quadrature modulator 5, the signal is ramped up to a strong transmission power at the end of the first TCH as shown in FIG. 4 (4). Then, the waveform generation unit 4 multiplies the Ich and Qch generation waveforms by the data obtained by adding the two-stage ramp-down data to the normal ramp-down data in the first 2-bit section of the SF or TCH, and the Ich and Qch generated by the two-stage ramp-down process. By inputting Qch to the quadrature modulator 5, as shown in FIG. 4 (4) or (4 ′), it is ramped down to a predetermined transmission power in the first 2-bit section of SF or TCH. After that, after the second TCH is transmitted with the normal transmission power, the normal ramp-down data is multiplied in the first 4-bit section of G, and the Ich and Qch subjected to the normal ramp-down process are input to the quadrature modulator 5. As shown in FIG. 4 (1), the ramp-down is performed at G, the transmission power is lowered to the transmission off state, and the process ends in ST5-10. As a result, SW and CC for synchronization at the weak electric field level or transmission power for transmitting SF and SACCH in addition to these are ramped up to a level exceeding a predetermined level, so that establishment of synchronization of the base station is stable. Communication quality by transmission can be improved.
[0020]
As described above, according to the first embodiment, by controlling the transmission power as necessary according to the reception level, it is possible to reduce the power consumption and improve the communication quality in the weak electric field. .
[0021]
The reception level used in the first embodiment may be any value as long as A>B> C.
[0022]
Embodiment 2. FIG.
In the second embodiment, transmission power two-stage ramp processing according to the remaining battery capacity will be described.
FIG. 6 is a flowchart showing the operation of the ramp processing according to the second embodiment.
[0023]
First, the control unit 14 monitors the remaining battery capacity at regular intervals, determines whether the transmission process is performed in ST6-1, ST6-2, and in this determination, if the transmission process is not started, Return to ST6-1.
[0024]
If the transmission process is started in ST6-2, ST6-3 compares the remaining battery capacity monitored in ST6-1 with the predetermined value D.
As a result of the comparison, if the remaining battery capacity is smaller than the predetermined value D, it is determined that the remaining battery capacity is very low, and the power saving ramp process, that is, transmission similar to ST5-5 in the first embodiment is performed. The transmission process is performed with power, and the process ends in ST6-4. As a result, when the remaining battery capacity is very low, power consumption due to transmission can be reduced.
[0025]
Next, when the battery remaining capacity is equal to or greater than the predetermined value D in the comparison result of ST6-3, the monitored battery remaining capacity is compared with the predetermined value E in ST6-5.
As a result of the comparison, if the remaining battery capacity is smaller than the predetermined value E, it is determined that the remaining battery capacity is slightly reduced, and the two-stage power save ramp process similar to ST5-7 in the first embodiment is performed. ST6-6, the process ends. As a result, when the remaining battery capacity is reduced, it is possible to reduce power consumption by transmission while ensuring communication quality.
[0026]
If the remaining battery capacity is equal to or greater than the predetermined value E in the comparison result of ST6-5, it is determined that the remaining battery capacity is still sufficient, and the normal ramp process similar to ST5-9 of the first embodiment is performed to perform ST6- 7. End the process.
[0027]
In this way, by controlling the transmission power according to the battery remaining capacity, the power consumption when the remaining battery capacity is reduced can be reduced, and the communication time can be extended.
[0028]
Note that the remaining battery capacity used in Embodiment 2 may be any value as long as D> E.
[0029]
In the first and second embodiments, the ramp-up and ramp-down control is processed by the waveform generation unit 4, but may be processed by the TDMA circuit 3, or may be processed after modulation by the quadrature modulator 5. Alternatively, the power amplifier 7 may process so that the power is changed only in the corresponding bit portion.
[0030]
In Embodiments 1 and 2, the PDC communication method has been described. However, any communication method can be applied as long as it is a communication method that establishes synchronization and transmits transmission data.
[0031]
Further, in Embodiments 1 and 2, only TCH transmission has been described, but the present invention can also be applied to packet transmission and VOX transmission that is transmitted instead of TCH during a silence period.
[0032]
【The invention's effect】
In the wireless communication device according to the present invention, the transmission power of the transmission wave portion corresponding to the bit position for synchronization in the transmission data is increased in a ramp shape from the predetermined transmission power in the other transmission wave portions. The establishment of station synchronization can be stabilized, and the communication quality can be improved reliably.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a conventional wireless communication apparatus according to the present invention.
FIG. 2 is a diagram showing a time slot configuration example of a conventional and the PDC system according to the present invention.
FIG. 3 is a diagram illustrating a transmission slot configuration of a conventional wireless communication apparatus according to the present invention.
FIG. 4 is a diagram showing a ramp process during a transmission burst according to the present invention.
FIG. 5 is a flowchart showing an operation of ramp processing according to the first embodiment.
FIG. 6 is a flowchart showing an operation of ramp processing according to the second embodiment.
[Explanation of symbols]
4 Waveform Generation Unit 5 Quadrature Modulator 7 Power Amplifier 10 Receiver 14 Control Unit

Claims (3)

A waveform generation unit that converts transmission data into a baseband signal, an orthogonal modulation unit that modulates the baseband signal converted by the waveform generation unit, and a transmission wave that is transmitted from the antenna by the modulated wave modulated by the orthogonal modulation unit A power amplifying unit for amplifying, and a control unit for controlling the transmission power of the transmission wave, wherein the transmission power of the transmission wave part corresponding to the bit position for synchronization in the transmission data is predetermined in the other transmission wave part A wireless communication device characterized in that the transmission power is larger in a ramp shape than the transmission power. A waveform generation unit that converts transmission data into a baseband signal, an orthogonal modulation unit that modulates the baseband signal converted by the waveform generation unit, and a transmission wave that is transmitted from the antenna by the modulated wave modulated by the orthogonal modulation unit A power amplifying unit for amplifying, and a control unit for maintaining constant transmission power during a burst period for transmitting the transmission data, and transmitting power at a position corresponding to a bit for synchronization in the transmission data A wireless communication apparatus characterized in that it is larger than a certain transmission power in a ramp shape. The reception unit for detecting a reception level of a signal received via an antenna is provided, and the transmission power of the transmission wave is changed according to the reception level received by the reception unit. Wireless communication device.

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