JPH08274756A - Radio communication system - Google Patents

Abstract

PURPOSE: To secure the transmission quality of a down link and simplify the constitution of a portable electronic device. CONSTITUTION: The transmission rate change request signal detection part 005 of a base station 000 extracts a signal requesting a change in the signal transmission rate (signal transmission rate of down link) at the time of the transmission of a signal from the base station 000 to the portable electronic device 001, and performs operation for changing the signal transmission rate of the down link. A modulation part 007 changes the signal transmission speed and outputs a modulated signal to the portable electronic device 001. A propagation path estimation part 013 estimates a propagation path between the base station 000 and portable electronic device 001 and outputs the estimation result to a control part 014. The control part 014 judges whether or not the signal transmission rate of the down link is changed from the output of the propagation path estimation part 013 and generates and outputs a change request signal to a modulation part 015 when the transmission rate is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a downlink transmission rate at which a base station transmits a signal to the portable electronic device faster than an uplink transmission rate at which the portable electronic device transmits a signal to a base station. In the wireless communication system in which the uplink transmission rate and the downlink transmission rate are asymmetric,
The present invention relates to a wireless communication system in which a downlink is faster than an uplink and a large amount of information is transmitted from a base station to a portable electronic device in response to a small amount of information transmission request from the portable electronic device.

[0002]

2. Description of the Related Art In wireless communication, as a conventional example of a transmission system characterized by a variable transmission rate, there is a technical report, RCS94-
64 (1994-09), pp. 31-36, “Transmission Characteristic Analysis of Symbol Rate / Modulation Multilevel Variable Adaptive Modulation Method”. The above document discloses a method of changing the modulation multi-level number and the symbol rate according to the transmission path condition under the constraint that the transmission quality is kept constant. Since the multiplexing method is TDMA / TDD, the radio signal output from the base station to the mobile electronic device and the radio signal output from the mobile electronic device to the base station are subject to the same channel fluctuation. Utilizing this reversibility, the transmission channel condition estimation unit of the base station calculates the instantaneous C / N and estimates the transmission channel. In this method, since the multiplexing method is TDMA / TDD, the base station can estimate the transmission path. Conversely, the applicable system is limited because the multiplexing method is limited.

FIG. 33 shows types of selectable transmission rates in the above literature. The change of multi-level number is QPSK, 16Q
AM, 64QAM and 256QAM. The change in symbol rate is 8 ksymbol / s, 16 ksy
mb / s, 32 ksymbol / s, 64 ksym
bol / s. As described above, the signal transmission speed of the system which has been conventionally transmitted by radio is at most several tens of ksym.
bol / s, and the occupied frequency band is about several tens of kHz.

Transmission line distortion occurs due to multipath and fading. Multipath occurs because the propagation path between the base station and the portable electronic device is not only a component that directly reaches it but also a component that is multiply propagated by the building. The delayed wave component due to multiple propagation is generated at a constant value regardless of changes in the signal transmission rate. Therefore, the influence of transmission path distortion due to multipath becomes more severe as the signal transmission speed increases. In addition, when trying to perform high-speed transmission under a multipath environment, it is usually necessary to use a very complex and large-scale adaptive equalization circuit.

By the way, as a method for ensuring high transmission quality and improving reliability of information communication, there is a method using an error correction code. In communication using an error correction code, a signal encoded by an encoding device on the information transmitting side is decoded by a decoding device on the receiving side. Satellite communication is an example of communication using error correction codes. In satellite communication, error correction technology is used to reduce the power consumed by the satellite itself. In addition, various error correction codes have been developed for use in various applications.

Like satellite communication, it is necessary to suppress power consumption on the transmitting side (satellite), and there is an apparent power difference such that there is virtually no restriction on the receiving side (base station) on the ground. In this case, the encoding device has a simple configuration so that the power consumption is small, and the decoding device is complicated even if the power consumption is large.

Further, normally, in information communication using an error correction code, decoding processing is troublesome. In principle, the decoding process has an enormous table that lists all possible received codes and the corresponding information symbols, and refers to this table to correct the received code. is there. In fact, the structure having a table is used to enable efficient decoding processing (rather than drawing a table). It is necessary to lengthen the code length in order to improve the error correction capability, but if the code length is lengthened, the processing device becomes complicated and power consumption increases. Furthermore, when performing high-speed processing, pipeline processing must be performed using multiple error correction devices, which means that multiple error correction devices with the same structure are prepared. Power consumption is further increased.

In the communication system using the conventional error correction device, the error correction decoding device is always operated to perform information communication using the error correction code regardless of the quality of the transmission path. In other words, it means that the transmission line quality is good and the device is operating even if error correction is not required, and it means that the device that consumes a lot of power is operating wastefully. By the way, in recent years, "you can communicate with anyone anytime, anywhere"
There is an increasing demand for mobile communication using portable electronic devices. In addition, multimedia communication that "can communicate with anything" is also attracting attention. That is, in the past, when a portable electronic device was used, communication using only voice was mainly performed, but in recent years, in addition to voice, various types of information communication such as character information, image information, and moving image information are performed. Therefore, the demand for reliability of communication is increasing. Furthermore, multimedia type mobile communication in which "anytime, anywhere, with anyone" and "anything" are integrated can be considered, and it can be considered that the demand for reliability of communication is further increased.

The problem of reliability in the portable electronic device of multimedia type mobile communication is opposite to that of the satellite communication described above. That is, although the same is true in that communication using an error correction code is performed in order to increase the reliability of communication, the relationship of power that can be consumed is reversed. The portable electronic device has a limitation in power that can be consumed for size reduction and weight reduction, and cannot consume a large amount of power for error correction. In this case, the transmitting station is the base station, and compared to the portable electronic device,
There are few restrictions on power consumption.

In other words, the demand for communication reliability is increasing in a situation where the power limit is severer.

[0011]

As described above, in the conventional wireless communication, when the downlink from the wireless base station to the portable electronic device is constructed at a fixed transmission rate, for example, a high-speed transmission of about 150 Mbps is attempted. , There was a problem that communication could not be performed at all in the place where multipath existed. Furthermore, if a line design is performed in consideration of multipath, only a low speed link can be realized, and only a low speed transmission can be performed even in a place where there is no multipath. Also, when trying to perform high-speed transmission in a multipath environment, a very complicated and large-scale adaptive equalization circuit is used, which causes obstacles to downsizing of a terminal (portable electronic device) and low power consumption. Was becoming.

Further, in the mobile electronic device of multimedia type mobile communication for performing information communication by using the error correction code, there is a problem that the demand for reliability is high in spite of the large restriction on power consumption. Therefore, a wireless communication system capable of reducing the power consumption of the portable electronic device while ensuring high reliability has been demanded.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to reduce an error generated in a signal transmitted from a base station to a portable electronic device and to determine whether or not multipath exists. Despite this, it is an object of the present invention to provide a wireless communication system capable of improving overall transmission efficiency while ensuring high downlink transmission quality and further simplifying the configuration of a portable electronic device.

Another object of the present invention is to secure a high transmission quality by using an error correction code, reduce power consumption, enable a simple portable electronic device configuration, and improve the overall transmission efficiency. It is to provide a wireless communication system capable of performing the above.

[0015]

In order to solve the above problems, in a wireless communication system according to the present invention, the downlink transmission rate is controlled in a wireless communication system in which the downlink transmission rate and the uplink transmission rate are asymmetric. It is characterized by being independently variable.

Further, in the conventional variable transmission rate wireless communication system, since the multiplexing system is TDMA / TDD, the communication from the base station to the portable electronic device and the communication from the portable electronic device to the base station are performed. From either direction of
Radio propagation characteristics between the base station and the portable electronic device are assumed to exhibit substantially equivalent characteristics. However, when the premised system is a wireless communication system in which the transmission rate is asymmetric, the radio propagation characteristics between the base station and the portable electronic device are not reversible, and therefore the base station cannot estimate the transmission path. Can not. As described above, the conventional system in which the base station determines the transmission rate cannot realize the variable transmission rate.

Therefore, in the present invention, the portable electronic device has means for estimating the radio propagation state with the base station, and transmits the radio propagation state obtained by the estimating means to the base station by a radio signal. It is characterized by changing the downlink transmission rate.

Further, the portable electronic device has means for estimating a radio propagation state with the base station and means for determining a downlink transmission rate from the radio propagation state obtained by the means, and the portable electronic device is a base station. It is characterized in that a request for changing the downlink transmission speed is transmitted to the station by a radio signal.

In order to use the radio wave propagation state from the base station to the portable electronic device as an index when changing the downlink transmission rate, the portable electronic device estimates the transmission path, and the maximum is obtained from the obtained results. It is necessary to provide a circuit that determines the transmission rate. However, the configuration of the portable electronic device needs to be simple as described above.

In order to meet these conflicting requirements, in the present invention, the base station changes the downlink transmission rate for each predetermined period, and the base station changes the maximum transmission rate that the portable electronic device can receive. To a wireless signal,
The transmission rate of the downlink is determined.

Further, a changing method for changing the downlink transmission rate for each predetermined period is characterized in that the high transmission rate is sequentially changed to the low transmission rate.

Further, in a wireless communication system with asymmetric transmission rates, the amount of signal transmission from the portable electronic device to the base station is smaller than the amount of signal transmission that can be transmitted from the base station to the portable electronic device. Therefore, it is desired that the amount of uplink transmission be as small as possible.

Therefore, according to the present invention, in a wireless communication system in which a downlink transmission rate is discretely determined in advance between the base station and the portable electronic device, the portable electronic device moves from the base station to the portable electronic device. The portable electronic device comprises: means for detecting an error in a signal wirelessly transmitted to the electronic device; and means for determining a transmission rate of the downlink according to a transmission error situation obtained from the means, It is characterized in that the base station is requested to increase or decrease the transmission rate by one step.

From the viewpoint of effective use of channels, it is desirable that there is no useless communication in the portable electronic device that makes reception impossible. When the transmission line characteristics fluctuate due to shadowing or the like and the transmission quality deteriorates, the base station and the portable electronic device make settings so as to slow down the downlink signal transmission speed in order to improve the communication quality. If the communication quality cannot be secured even if the communication is performed at the lowest transmission rate, the operation of slowing the transmission rate becomes useless.

Therefore, in the present invention, in a wireless communication system in which the downlink transmission rate is determined in advance between the base station and the portable electronic device, a signal in which the downlink transmission rate is determined in advance is provided. When the portable electronic device issues a request to further reduce the downlink transmission speed at the lowest transmission speed, the communication from the base station to the portable electronic device is cut off. It is characterized by

In a communication system having an asymmetric transmission rate, the transmission rate from the base station to the portable electronic device is larger than that in the uplink because the downlink transmission rate is high. Therefore, it is possible to frequently insert a known signal for channel estimation.

Therefore, the present invention is characterized in that the base station device periodically inserts a known signal for channel estimation into communication from the base station to the portable electronic device.

As described above, in the conventional variable transmission rate communication system, the access system is TDMA / TDD.
Is assumed. Therefore, when the signal transmission rate is changed according to the transmission path condition, the uplink transmission rate and the downlink transmission rate are changed at the same time. In addition, since the base station can estimate the transmission path, the base station can change the transmission rate only by notifying the change in the transmission rate. However, if the base station cannot estimate the transmission path, the base station alone cannot determine the transmission rate.

Therefore, in the present invention, the base station or the portable electronic device makes a decision to change the transmission rate of the downlink based on the radio propagation state obtained by the estimating means, and the downlink and It is characterized in that the base station and the portable electronic device determine the timing of changing the signal transmission rate using a control channel prepared for the uplink.

A portable electronic device equipped with a wireless device,
A downlink transmission speed for transmitting a signal to the portable electronic device, the base station receiving a wireless signal from the portable electronic device and transmitting information to the portable electronic device by a wireless signal. However, in a wireless communication system in which the mobile electronic device transmits a signal to the base station at a speed higher than an uplink transmission speed, the mobile electronic device can obtain an information sequence by only removing redundancy. A signal representing a symbol string that has been error-correction-encoded by using a radio signal is transmitted as a radio signal, the receiving device converting the transmitted signal into a symbol string, and the symbol string obtained by the receiving device are decoded. Error correction decoding device for performing error correction, and redundancy for removing only the redundancy without decoding the symbol string obtained by the reception device Removing device, a transmission quality estimating device that estimates the transmission quality of the transmission path on which the wireless signal received by the receiving device is transmitted, and the transmission quality estimated by the transmission quality estimating device is determined to be inferior to the reference quality. In this case, the error composed of the switching means for processing the symbol string by the error correction decoding device and processing it by the redundancy removing device when it is determined that the transmission quality satisfies the reference quality. It is characterized by comprising a correction device.

In addition to the estimation of the transmission quality by the transmission quality estimation device, the error correction device can control the selection of the processing of the symbol string, that is, the selection of the error correction device and the redundancy removal device from an external device. Is characterized by.

Further, even if the transmission quality estimating apparatus has an error detecting apparatus capable of detecting that the symbol string contains an error and the transmission quality estimating apparatus selects the redundancy removing apparatus, the error detecting apparatus detects an error. It is an error correction device characterized by detecting.

There are several types of information to be transmitted, and the information is error-correction-coded from among a plurality of error-correcting codes, which is most suitable for the type of information. An error correction device having a plurality of decoding devices corresponding to an error correction code and selecting a decoding device from the decoding devices according to the form of the information.

Further, it comprises a portable electronic device equipped with a wireless device and a base station for receiving a wireless signal from the portable electronic device and transmitting information to the portable electronic device by a wireless signal. In a wireless communication system in which a downlink transmission rate for transmitting a signal to the portable electronic device is higher than an uplink transmission rate for transmitting a signal to the base station by the portable electronic device,
The base station has an error correction coding device that performs error correction coding on a wireless signal to be transmitted to the mobile electronic device, and the mobile electronic device performs error correction to perform error correction decoding on the error correction coded wireless signal. It has a decoding device and a transmission line quality estimation device for estimating the transmission line quality of the transmission line on which the wireless signal is transmitted, and the transmission quality estimation device of the portable electronic device determines that the transmission quality is lower than the reference quality. If the error correction coding device transmits the error-correction coded wireless signal and the error correction decoding device decodes the signal, it is determined that the transmission quality satisfies the reference quality. It is characterized in that the error correction decoding apparatus is stopped without performing correction coding.

Further, in the wireless communication system using error correction, when it is determined that the transmission quality satisfies the reference quality, the error correction device is stopped and the error correction coding is performed by the transmitting station. It is characterized in that the transmission rate is increased by notifying that the device is not used and embedding information without performing error correction coding on the transmitting station side.

Further, the transmitting station has a plurality of error correction coding devices for processing different error correction codes, and the receiving station has a plurality of error correction decoding devices corresponding to the plurality of error correction coding devices of the transmitting station. The receiving station estimates the transmission quality by the transmission quality estimation device, selects the most suitable error correction decoding device among the plurality of error correction decoding devices according to the transmission quality, and uses which error correction decoding device To the transmitting station, the transmitting station decides to use the error correction code corresponding to the error correction decoding device used by the receiving station, changes the error correction coding device to be used, and The wireless communication system is characterized in that the receiving station side is notified that the correction coding device has been changed, and the receiving station side that has received the notification changes the error correction decoding device.

Further, the receiving station notifies the transmitting station of the estimation of the transmission quality by the transmission quality estimating apparatus, and the transmitting station side selects the error correction code to be used, and the communication system using the error correcting apparatus. Is.

[0038]

According to the present invention, in a wireless transmission system having an asymmetrical transmission rate, it is possible to set the highest signal transmission rate under the condition of wireless propagation from the base station to the portable electronic device, and the total transmission capacity ( Throughput) can be improved.

The principle of the present invention will be described based on an example in which multipath distortion that fluctuates in the transmission path from the base station to the portable electronic device exists. In this wireless communication system, since the downlink transmission speed is increased, many errors occur in the transmission signal in the multipath environment. In the portable electronic device, the wireless propagation situation from the base station to the portable electronic device is estimated based on the signal transmitted wirelessly from the base station, and the estimated result is the fastest transmittable speed in the portable electronic device or the base station. Determine the transmission rate of. The portable electronic device requests to reduce the signal transmission rate when the propagation condition between the base station and the portable electronic device is bad. When the transmission speed is reduced, the amount of signal transmission that can be transmitted within a unit time is reduced, but the error of the transmission signal is reduced.

Further, when the radio propagation condition is bad, ARQ is performed to compensate for a code error. That is,
ARQ is frequently performed due to many code errors. This reduces throughput. In the present invention, it is possible to reduce the occurrence of code errors by lowering the signal transmission rate and improving the noise resistance characteristics. As described above, by reducing the signal transmission rate, the amount of information transmission itself decreases, but the ARQ due to the reduction of code errors.
The reduced transmission improves the overall transmission capacity.

On the other hand, when the influence of multipath distortion is small, sufficient performance cannot be obtained with a fixed transmission rate. This is because the signal is transmitted at a fixed low signal transmission rate although the transmission can be performed at a higher transmission rate. According to the present invention, the portable electronic device observes the radio propagation situation, and when it determines that the signal transmission rate can be further increased, it requests the base station to increase the signal transmission rate. In response to this request signal, the base station performs processing for increasing the downlink signal transmission rate. With the above method, it is possible to transmit the maximum rate according to the state of the transmission path, and the total transmission rate can be increased.

Further, since the downlink transmission rate is changed by the communication relating to the change of the transmission rate between the portable electronic device and the base station, the access method other than TDMA / TDD, which makes it impossible to estimate the transmission path on the base station side. Even in, the variable transmission rate can be realized and the total throughput is improved.

Further, since the predetermined downlink transmission rate is changed with time, the optimum signal transmission rate can be easily obtained in the portable electronic device, which can simplify the circuit configuration of the portable electronic device.

Further, by changing the signal transmission rate between the base station and the portable electronic device and determining the switching timing by the control channel, only the uplink transmission rate or only the downlink transmission rate is changed. It becomes possible.

Further, in order to secure high transmission quality and enhance reliability of information communication, a radio communication system which performs communication using an error correction code has the following effects.

In a situation where the transmission quality is good, error correction is not always necessary. Therefore, the power consumption is reduced by not operating the error correction device, which is expensive in terms of power consumption.

Further, the selection of the error correction decoding device and the redundancy removing device can be controlled by a device other than the transmission quality estimating device. For example, since the remaining amount of power stored in the terminal has decreased, you can tolerate some errors, so if you want to get the information to the end, the user must not operate the error correction device. Can be selected as desired.

Further, even if an error occurs when the error correction device is not operating to reduce power consumption, the error detection device detects the existence of the error and corrects the error by means such as retransmission. It is also possible to guarantee high reliability. Since the error detection device generally has a smaller circuit size and lower power consumption than the error correction device, compared to the case where the error correction device is always operated,
It is possible to reduce power consumption.

Further, by making it possible to select the most suitable error correction decoding device according to the form of information from among a plurality of prepared devices, efficient communication can be performed.

Further, since the error correction is performed when the transmission quality is poor, highly reliable transmission can be performed, and when the transmission quality is good, the error correction is not performed, so that the power consumption is suppressed and further the error correction is performed. It is possible to increase the transmission rate as compared with the case of performing it.

Since the information is embedded in the redundant portion of the error correction code, the length of the code word does not change apparently.
Another feature is that the device is simple.

Further, since the most suitable code can be selected from the plurality of error correction codes according to the transmission quality, power consumption can be suppressed and communication efficiency can be improved.

Although the receiving station side estimates the transmission quality, the transmitting station side determines what operation is to be performed based on the estimation result. Therefore, the receiving side determines the circuits, power, etc. required for the determination. It is not necessary to have it, and the circuit scale and power consumption are saved. Furthermore, when making a decision, the transmitting station side can use not only the report from the receiving station side but also various other information. For example, when there is a correlation between the position of the receiving station and the transmission quality, such as radio waves, the transmitting station can improve the accuracy of the estimation of the transmission quality by creating a database regarding the position and the transmission quality. .

[0054]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a data communication system using a wireless communication system according to the present invention. A wireless communication system according to the present invention includes a portable electronic device including a wireless device and a base station that receives a wireless signal from the portable electronic device and transmits information to the portable electronic device by the wireless signal.

In a wireless transmission system for performing wireless communication between a base station and a portable electronic device, the signal transmission rate is asymmetric, that is, the downlink transmission rate at which the base station 12 transmits a signal to the portable electronic device is portable. The SDL (Super high speed DownLink) system is faster than the uplink transmission speed for transmitting a signal from the electronic device 10 to the base station 12. Here, the downlink transmission is narrow (there may be a wide-area downlink), and the uplink transmission is wide.

For example, the base station uses a high-bandwidth signal for downlink transmission to provide services (multimedia services) such as communication including images, voice, file editing, information distribution / publicity, and broadcasting to the portable electronic device. To provide. Portable electronic devices use narrowband signals for uplink transmission,
Information for controlling the downlink, channel selection, control signals for media selection in the case of multimedia, voice data, etc. are transmitted to the base station.

When there are a plurality of portable electronic devices in the area covered by the base station (communicable with the portable electronic devices), the portable electronic devices are updated to the maximum extent possible. Establish link and downlink circuits.

The base station is connected to, for example, a network, and acquires the above-mentioned service via the network and provides it to the portable electronic device in response to a request from the portable electronic device. As shown in FIG. 1, in addition to a plurality of base stations, a database system, various control systems, terminals (not shown), etc. are connected to the network so that information can be mutually transmitted and received. ing. The portable electronic device can use various information services via a network by using a wireless transmission system with the base station.

In the SDL system, a large amount of data can be transferred from the base station to the portable electronic device in order to realize a multimedia service for providing arbitrary information to the portable electronic device from an arbitrary point. Need to be
Therefore, the downlink transmission rate is desired to be as high as possible. Moreover, it is desired that the portable electronic device be as small as possible. The miniaturization of portable electronic devices is realized by sacrificing the signal transmission speed from the portable electronic devices to the base station.

Consider the adoption of the TDD scheme in a multimedia wireless communication system that uses a high-speed downlink and provides various information from a base station to a portable electronic device.
The distance between the base station and the mobile station is arbitrary and therefore TDD
In order to prevent the transmission from the mobile station and the transmission from other mobile stations from colliding with the transmission from the base station, the uplink of the system is provided with a time interval called a guard time.

Such a multimedia wireless communication system assumes a very high speed line. The time due to the guard time means that the time during which the information signal can be transmitted is reduced, which causes a reduction in the total transmission speed. Further, when the TDD method is used, the base station and the portable electronic device need to use the same frequency band and signal transmission speed. However, this restriction imposes a great burden on the transmitter of the portable electronic device, and makes it difficult to realize downsizing and low power consumption of the portable electronic device that constitutes the portable electronic device.

Further, in the SDL system, since the downlink transmission rate is higher than the uplink transmission rate, it is difficult to adopt TDMA / TDD as the multiplexing system. Therefore, as in the conventional method, TD
This means that the radio base station cannot directly estimate the transmission path between the base station and the portable electronic device by taking advantage of the characteristic of D. The portable electronic device is required to be as simple as possible in configuration, but the fact that the transmission path cannot be estimated by the base station is a factor that impedes this request for simplification.

In a wireless communication system having an asymmetric transmission rate such as the SDL system, the downlink transmission rate at which the base station transmits a signal to the portable electronic device is the downlink transmission rate at which the portable electronic device transmits a signal to the base station. Since the uplink transmission speed is higher than the uplink transmission speed, an error is likely to occur in the signal transmitted from the base station to the portable electronic device.

However, dozens of ksym that have been conventionally performed.
At a transmission rate of about bol / s, this did not pose a problem. In addition, the influence of the transmission path distortion due to the multipath also appears prominently as the downlink speed increases, and becomes a factor that hinders the downlink transmission quality. When multimedia services are provided by a wireless communication system with asymmetric transmission rates, the downlink transmission rate is up to several hundreds Msymb.
ol / s is also expected, and from this,
There is a need for means for compensating for errors due to channel distortion.

In the conventional wireless communication system of variable transmission rate, the transmission rates of the uplink and the downlink are about the same, and since the multiplexing system is TDMA / TDD, the communication from the base station to the portable electronic device is performed. From both directions of communication from the portable electronic device to the base station, the radio propagation characteristics between the base station and the portable electronic device show substantially equivalent characteristics. However, if the base system is a wireless communication system with asymmetric transmission rates, the wireless propagation characteristics between the base station and the portable electronic device are not reversible, and therefore the base station must estimate the transmission path. I can't. As described above, it has been difficult to apply the conventional method to an asymmetric wireless communication method such as an SDL system in which the transmission rate differs by one digit or more.

A specific structure for solving these problems will be described below.

First, a wireless communication system according to the first embodiment of the invention will be described with reference to FIG. The wireless communication system of the first embodiment can change the downlink transmission rate. FIG. 2 is a block diagram showing the configurations of the base station 000 and the portable electronic device 001 of the wireless communication system in the first example.

Although one base station 000 and one portable electronic device 001 are shown in FIG. 2, in addition to the one-to-one communication between the base station and the portable electronic device, one base station is portable. It is possible that there are a large number of electronic devices, there are a plurality of base stations for one portable electronic device, and there are a plurality of base stations and a plurality of portable electronic devices. Since the same configuration is adopted in any case, here, for simplification of description, a case where a large number of one portable electronic device 001 exists for one base station 000 will be described as an example.

The base station 000 has antennas 002, 00
9, RF unit 033, 008, demodulation unit 004, transmission rate change request signal detection unit 005, control unit 006, modulation unit 007
It is composed by. In addition, the portable electronic device 001
Are antennas 010 and 017, RF units 011 and 016,
The demodulation unit 012, the propagation path estimation unit 013, the control unit 014, and the modulation unit 015 are configured.

In the base station 000, the signal from the portable electronic device 001 is received by the antenna 002, amplified by the RF section 003, and then demodulated by the demodulation section 004. The transmission rate change request signal detection unit 005 requests the change of the signal transmission rate (downlink signal transmission rate) when the signal is transmitted from the base station 000 to the portable electronic device 001 from the output signal of the demodulation unit 004. Signal to be extracted, and the control unit 006
Output to. The signal requesting the change of the downlink signal transmission rate is transmitted from the portable electronic device 001. The control unit 006 performs an operation of changing the downlink signal transmission speed according to the output of the transmission speed change request signal detection unit 005. The modulator 007 changes the signal transmission rate according to the output of the controller 006 and outputs the modulated signal to the portable electronic device 001. In the RF unit 008, the modulation unit 007
The modulated signal which is the output from the antenna is amplified and transmitted from the antenna 009.

In the portable electronic device 001, the signal transmitted from the base station 000 is received by the antenna 010, amplified by the RF unit 011 and then demodulated by the demodulation unit 012.
Furthermore, from the output of the demodulation unit 012, the propagation path estimation unit 013
Estimates the propagation path between the base station 000 and the portable electronic device 001 and outputs the estimation result to the control unit 014. The control unit 014 determines from the output of the propagation path estimation unit 013 whether or not to change the downlink signal transmission rate. When changing the transmission rate, a change request signal is created and the modulation unit 0
Output to 15. The modulated wave output from the modulator 015 is
It is amplified by the RF unit 016 and transmitted from the antenna 017.

With the above configuration, it is possible to change the downlink signal transmission rate from the base station 000 to the portable electronic device 001.

Next, a radio communication system according to the second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows a configuration on the portable electronic device 10 side for determining the downlink transmission rate from the base station in the wireless communication system including the base station and the portable electronic device. In the second embodiment, the base station side determines the downlink transmission rate.

The portable electronic device 10 is a base station (not shown).
A reception antenna 11 for receiving a radio signal transmitted from a mobile electronic device to a portable electronic device, a reception R for selecting a radio signal and performing RF amplification
F section 12, variable frequency oscillator 13 that is a local oscillator for converting an RF signal into a baseband signal, mixer 14 that mixes the output of receiving RF section 12 and the output of variable frequency oscillator 13, and unnecessary after mixing by mixer 14. A low-pass filter 15 for removing an image, a demodulation unit 16 that functions as a modem for demodulating the output of the low-pass filter 15 into a data signal, a known signal portion is detected from the data signal demodulated by the demodulation unit 16, and the known signal portion is detected. A known signal detecting section 17 for extracting a signal, and a correlator 1 for obtaining transmission path information by correlating the output of the known signal detecting section 17 and the known signal
8. Memory 1 for buffering output of correlator 18
9, a transmission path estimation data creation unit 20 that creates transmission path estimation data for the base station, a control unit 21 that controls the correlator 18, the memory 19, and the transmission path estimation data creation unit 20, and a transmission path estimation data creation unit 20. A modulator 22 for converting the output to a baseband signal, a low-pass filter 23 for band-limiting and shaping the output of the modulator 22, a variable frequency oscillator 24 as a local oscillator for up-converting to RF, and a low-pass filter 23. A mixer 25 that mixes the output and the output of the variable frequency oscillator 24, a transmission R that removes the unnecessary image after mixing and amplifies the RF signal to the output level
The F section 26 and the transmission antenna 27 radiate a radio signal obtained by amplification by the transmission RF section 26 to the base station.

In the portable electronic device 10, the known signal detector 1 detects the data signal demodulated by the demodulator 16.
7 detects the timing of a known signal included in the data signal and notifies the control unit 21 of the timing. The control unit 21 notified of the known signal timing operates the correlator 18 and the memory 19. Further, the known signal detector 17 extracts the known signal portion from the demodulated data signal at the same time as detecting the known signal timing. The correlator 18 correlates the demodulated known signal portion with a known signal serving as a reference held by the mobile electronic device 10, and outputs the result to the memory 19. Since the correlation output changes depending on the transmission path condition, the operation of determining the optimum downlink transmission rate from the output of the correlator 18 is performed by a base station (not shown). The portable electronic device 10 transmits the correlation output stored in the memory 19 to the base station as information for the base station to determine the transmission rate.

With the above configuration, the base station can obtain the information for determining the downlink signal transmission rate, and the communication can be performed at the optimum transmission rate.

Next, a radio communication system according to the third embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a configuration on the portable electronic device 10 side for determining the downlink transmission rate from the base station in the wireless communication system including the base station and the portable electronic device. In the second embodiment, the downlink transmission rate is determined on the base station side, but in the third embodiment, it is performed by the portable electronic device 10.

In the portable electronic device 10 in FIG. 4, the same parts as those in the portable electronic device 10 shown in FIG. 3 are designated by the same reference numerals. The mobile electronic device 10 according to the third embodiment includes a reception antenna 11, a reception RF unit 12, and a variable frequency oscillator 1.
3, mixer 14, low-pass filter 15, demodulator 16,
Known signal detector 17, correlator 18, memory 19, modulator 22, low-pass filter 23, variable frequency oscillator 24,
The transmission rate is changed based on the determination result by the wireless propagation status determination circuit 31 and the wireless propagation status determination circuit 31 that determines the wireless propagation status using the mixer 25 and the output of the memory 19 that buffers the output of the correlator 18. As described above, the correlator 18, the memory 19, the radio propagation status determination circuit 30, and the transmission rate change request are generated according to the timing output from the transmission rate change request data creation unit 31 and the known signal detection unit 17 that generate the signal requested to the base station It is composed of a control unit 32 that controls the data creation unit 31 and a received electric field strength measurement detection unit 33 that measures the received electric field strength.

Similar to the second embodiment, in the portable electronic device 10, the known signal detecting section 17 detects the timing of the known signal included in the data signal with respect to the data signal demodulated by the demodulating section 16. Notify the control unit 32.
The control unit 21 notified of the known signal timing operates the correlator 18, the memory 19, and the radio propagation state determination circuit 30. The correlation output output from the correlator 18 is stored in the memory 19
Is stored. The radio propagation status determination circuit 30 includes a condition table for determining the radio propagation status according to the correlation output, and based on the condition table, determines whether to change the downlink transmission rate, This is output to the transmission rate change request data creation unit 31. Based on the output of the radio propagation status determination circuit 30, the transmission rate change request data creation unit 31 creates a code requesting the base station to change the downlink signal transmission rate. This request signal is transmitted to the base station by the uplink signal.

In the above description, the correlator output is used as the information for determining the transmission rate, but it is also possible to use the reception electric field strength detected by the reception electric field strength detection unit 33 at the same time. Received field strength detector 33
Outputs the detection result to the radio propagation status determination circuit 30.

With the above configuration, it is possible to change the downlink signal transmission rate, and it is possible to perform communication at the optimum transmission rate.

Next, a radio communication system according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 shows a sequence between the base station and the portable electronic device in the second embodiment shown in FIG.

In the downlink signal transmitted from the base station to the portable electronic device, a unique word (known information) for estimating the transmission path condition is inserted every certain period. The portable electronic device performs channel estimation (40) that correlates with the unique word. The declaration (41) of the transmission path estimation result from the portable electronic device to the base station is made periodically according to the execution of the transmission path estimation. The base station receives the result of the transmission path estimation declared by the portable electronic device and determines whether or not to change the downlink transmission rate (transmission rate variable determination 42).

Determination of Variable Transmission Rate at Base Station (4
As a result of 2), if the downlink transmission rate is the same as the current one, the base station notifies the portable electronic device of only the downlink transmission rate (transmission rate notification 43).
When the transmission rate is changed as a result of the transmission rate variable determination (42), the base station informs the portable electronic device of the fact that the transmission rate is changed, the changed transmission rate, and the change timing (44).

After the base station notifies the portable electronic device that the transmission rate is to be changed (44) and before the signal transmission rate is changed, the portable electronic device reports the transmission path estimation result (41). When it reaches the base station, the result is ignored (45). Further, the transmission path estimation (40) that is regularly performed in the portable electronic device is not performed (46) immediately after the downlink signal transmission rate is changed. In the base station, if the report 41 of the transmission path estimation result from the portable electronic device has passed a certain period, it is validated and a judgment (42) of variable transmission rate is made. Based on the result of the determination of variable transmission rate (42), if the transmission rate is the same as the current state, only the transmission rate is notified (43). In the case of changing the downlink signal transmission rate, the portable electronic device is informed of the fact that the transmission rate is changed at this point, the changed transmission rate, and the change timing (44).

In FIG. 5, the downlink signal transmission rate is shown as an example. 10 Ms before changing the transmission rate
symbol / s (47), the signal transmission speed is changed at the timing when the notification (48) for changing the signal transmission speed is received, and thereafter, the transmission is performed at 20 Msymbol / s (49). .

By the above sequence, the downlink signal transmission rate can be changed.

Next, a wireless communication system according to the fifth embodiment of the present invention will be described with reference to FIG. FIG. 6 shows a sequence between the base station and the portable electronic device in the third embodiment shown in FIG. In the fourth embodiment, the base station determines the transmission rate change, but in the fifth embodiment, the portable electronic device determines the transmission rate change.

Similar to the fourth embodiment, a unique word (known information) for channel estimation is inserted in the downlink signal transmitted from the base station to the portable electronic device. The portable electronic device detects the time when the unique word is inserted and correlates the unique word to estimate the transmission path (60). The portable electronic device uses the result of the transmission path estimation (60) to determine whether to change the downlink signal transmission speed (speed change determination 61) and change the currently set signal transmission speed. In this case, the signal transmission rate change request (62) is output to the base station. The portable electronic device does not estimate the transmission path until the base station responds to the change request.

At the base station, the transmission signal rate change request (6
2) In response, decide whether to change the transmission rate,
The portable electronic device is informed of the change in transmission rate and the change timing (64). After that, the transmission rate is switched to the change timing (65).

In the portable electronic device, the transmission path estimation 60 and the speed change determination 61 are restarted after the downlink signal transmission speed is changed, and when the transmission speed is desired to be further changed, the signal transmission speed change request 62 is output and If the transmission rate of 1 is acceptable, nothing is output (65). The base station periodically informs the portable electronic device of the downlink signal rate (66).

In FIG. 6, the downlink signal transmission rate is shown as an example. 10 Ms before changing the transmission rate
symbol / s (67), the signal transmission rate is changed at the timing of notification (65) of transmission rate switching, and thereafter, transmission is performed at 20 Msymbol / s (68). Furthermore, the notification of the subsequent transmission rate switching (6
At the timing of 9), the signal transmission rate is changed again and 10
Transmission is performed at Msymbol / s (70).

With the above sequence, the downlink signal transmission rate can be changed.

Next, a radio communication system according to the sixth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a flowchart showing a processing procedure when changing the downlink transmission rate in the base station. FIG. 7 shows a process 42 of the transmission speed variable determination 42 in which the transmission path estimation data is transmitted from the portable electronic device.

When the base station is notified of the correlation output as the transmission path estimation result by the portable electronic device, the base station starts the judgment of the variable transmission rate in the flowchart shown in FIG. First, the base station calculates the transfer characteristic between the base station and the portable electronic device using the declared correlation output (transmission path estimation 80). Further, the base station determines the optimum transmission rate r from the output and the condition table (optimum transmission rate determination 81).

Here, if the transmission rate r obtained by the optimum transmission rate judgment (81) is larger than the currently set downlink transmission rate a (82), the following processing is performed. First, it is determined whether or not the transmission rate r exceeds the upper limit of the downlink transmission rate that can be set (8
3) is performed, and if the upper limit is not exceeded, a process (84) for increasing the transmission speed is performed. On the other hand, if the transmission rate r exceeds the upper limit, nothing is done.

As a result of the comparison (82) of the transmission rates r and a, r
If not> a, if the transmission rate r is smaller than the currently set transmission rate a, the following processing is performed. First, it is determined whether the transmission rate r is below the lower limit of the downlink transmission rate that can be set (86), and if it is less than the lower limit, the cutoff process 87 is performed. on the other hand,
If the transmission rate r is less than the lower limit, a process (88) of lowering the transmission rate is performed.

When the interruption processing (87) is entered, the portable electronic device cannot receive information from the base station in the current transmission path condition, and unless the transmission path condition is recovered, the base station is not recovered. Communication from the mobile electronic device to the mobile electronic device is wasted. According to the present invention, since downlink communication is stopped in a situation where communication is not possible, it is possible to prevent unnecessary emission of radio waves. In addition, after the communication from the base station to the portable electronic device is cut off, in order to restart the communication, the line setting in the initial state is performed again. In an asymmetric wireless communication system in which the downlink transmission rate is higher than the uplink transmission rate, the uplink transmission quality from the portable electronic device to the base station is high. Therefore, uplink communication is possible even if the downlink is cut off. The line setting for restarting again after the downlink communication is interrupted by the procedure according to the present invention can be easily performed because the uplink communication is possible.

If the result of 85 is No, this procedure is terminated.

Next, a wireless communication system according to the seventh embodiment of the present invention will be described with reference to FIG. FIG. 8 shows downlink signals and uplink signals transmitted between the base station and the portable electronic device.

The downlink transmission rate is desired to be as high as possible. In order to set the optimum transmission rate, it is necessary to estimate the transmission path between the base station and the portable electronic device. However, as described above, when the access method is not TDMA / TDD, the base station cannot estimate the transmission path. It is also desired that the portable electronic device be as simple as possible. Therefore, the base station is shown in FIG.
As shown in, the downlink transmission rate is switched at a predetermined period To (90). rate1 (9
1) to rate4 (94) have different transmission rates. In the portable electronic device, after receiving all the transmission rates switched by the base station, the fastest transmission rate that the portable electronic device can receive is reported to the base station (transmission rate declaration 95). After that, communication is performed at the transmission speed declared by the portable electronic device (96).

Whether the portable electronic device can receive the radio signal from the base station can be determined by, for example, checking the parity of the received data. Since it is possible to determine whether or not the data can be received at the transmission speed declared by only the parity check, it is possible to simplify the circuit configuration of the portable electronic device.

As described above, it becomes possible to set the downlink signal transmission rate to the optimum value.

Next, a radio communication system according to the eighth embodiment of the present invention will be described with reference to FIG. FIG. 9 shows downlink signals and uplink signals transmitted between the base station and the portable electronic device. In the eighth embodiment, the signal transmission rate varying method in the seventh embodiment is performed in a shorter time.

The base station uses To (9
In 0), the downlink transmission rate is switched. On this occasion,
The speed is set in advance and the transmission speed is sequentially switched from the higher speed to the lower speed. In portable electronic devices, the r
A parity check is performed on the signal transmitted by ate4 (100), and if it is receivable, the transmission rate is reported to the base station (transmission rate declaration 101). If you cannot receive it, do not declare it. When the base station receives a transmission rate report from the portable electronic device, it switches to that transmission rate.

By the above method, the downlink transmission rate can be set to the optimum value. In this method, since the highest transmission rate is received, the highest transmission rate can be set in a short time in the state of the transmission path during communication.

Next, a radio communication system according to the ninth embodiment will be described.

In a communication system in which the uplink and downlink transmission rates are asymmetric, it is desirable that the uplink transmission amount be small. This is because the transmission speed is lower than that of the uplink, so that the transmission capacity of the downlink is small within a unit time. According to the ninth embodiment, it becomes possible to reduce the amount of uplink transmission.

FIG. 10 shows an uplink transmission signal 110 transmitted from the portable electronic device to the base station. An information signal (change request signal D) for periodically changing the downlink transmission rate is included in the transmission signal 110.
It is included. The change request signal D (111) is, for example, 2-bit information (D1, D0), and is (D1, D0).
When is (00), it means the current setting (112),
When it is (01), it means a request to increase the downlink transmission rate (113), and when it is (10), it means a request to reduce the downlink transmission rate (11).
4). The state where (D1, D0) is (11) indicates that there is no setting (115).

As described above, since only one change width of the set transmission rate is set for each downlink transmission rate change request transmitted from the portable electronic device to the base station, the transmission amount of the uplink is reduced. Can be reduced.

Next explained is a radio communication system according to the tenth embodiment.

In a system that realizes multimedia by high-speed wireless communication, signals transmitted from a base station to a portable electronic device are considered to be various such as image information, voice, and text. These pieces of information are originally output from different information sources, and are multiplexed into one signal when wirelessly transmitted. Generally, the system clock in each information source uses a unique frequency in each system. In the conventional wireless transmission system, the system clock is one and it is not designed to exist in plural numbers. Therefore, the transmission rate set by the variable transmission rate is set to the frequency obtained by dividing the system clock. However, since the information transmitted by the system that realizes the multimedia is originally the information obtained from the information sources of different system clocks, if the portable electronic device can cope with a plurality of system clocks, Information source multiplexing can be simplified.

FIG. 11 shows a signal transmission rate preset in the wireless communication system of the tenth embodiment. When varying the transmission rate, the transmission rate can be easily changed by creating a transmission rate correspondence table as shown in FIG. 11 in advance between the base station and the portable electronic device. In the example shown in FIG. 11, 10 Mbps (120)
8 to 70 Mbps (121) are set. When the portable electronic device wants to set the downlink signal transmission rate to 10 Mbps, it transmits the control code 01. The base station sets the transmission rate to 10 Mbps according to the signal transmission rate set in the transmission rate correspondence table shown in FIG.

The transmission rate correspondence table includes transmission rates that are not integral multiples of the system clock. Figure 11
Then, as an example, it is set to 53.24 Mbps (12
2). In a multimedia communication system in which there are many information sources of signals to be transmitted as described above, it is assumed that there are a plurality of different system clocks.
In that case, in order to multiplex data from a plurality of information sources into a transmission signal and coexist with data from other information sources, it is necessary to match the signal transmission rates. A conventional example of this method is stuff synchronization for inserting unnecessary bits.

In the communication system according to the present invention, since the signal transmission rate is variable, multiplexing is possible by varying the signal transmission rate for each data from different information sources. That is, the system clock of each information source (for example, 1
22) is entered in the transmission rate correspondence table as shown in FIG. 11 to enable multiplexing.

FIG. 12 is an eleventh embodiment showing the configuration of a demodulator in a portable electronic device when performing multimedia communication having a plurality of information sources having different system clocks. The radio signal transmitted from the base station is transmitted to the antenna 130.
And is decoded into a baseband signal by the MODEM 131. The control unit 132 monitors the output of the MODEM 131, switches the switch 133 according to the type of the information source, and operates the corresponding decoding unit from the plurality of decoding units 134. Each decoding unit 134 has a PLL 1 for clock synchronization.
34, and decodes the data of each information source from the input baseband signal. With the above configuration, it becomes possible to multiplex signals of information sources having different system clocks by changing the signal transmission rate.

Next, a radio communication system according to the twelfth embodiment of the present invention will be described with reference to FIG. FIG. 13 shows a method of generating a signal for detecting a transmission error.

The maximum transmission rate can be obtained by estimating the transmission path condition. The transmission path condition is estimated using the received signal and the known signal. Generally, the estimation of the transmission path requires a huge amount of calculation. According to the present invention, it is possible to perform signal transmission between the base station and the portable electronic device using the control channel to confirm the transmission quality. Therefore, it becomes possible to estimate the transmission path condition by changing the transmission rate and transmitting the signal and detecting the code error of the demodulated signal.

In FIG. 13, first, in rate1,
Check bit 142 for 3-bit data 141
Is added to 2 bits. In rate2, rate1
5 bits including the data part 141 and the check bit 142 at 10 bits (14 bits) at the transmission rate of rate2.
3), and a check bit 144 is added to the 10 bits (143). In rate3, 143
And 12 bits of 144 and 144 are converted into 24 bits (145) at the transmission rate of rate3, and a check bit 146 is added to 24 bits (145). The code error detection signal generated in this way is demodulated at each transmission rate,
The transmission rate can be determined by checking the check bit of each transmission rate.

Next explained is a radio communication system according to the 13th embodiment. FIG. 14 shows a part of the signals of the control channel according to the twelfth embodiment. As shown in the fourth embodiment, when changing the downlink transmission rate, the base station notifies the changed signal transmission rate and the change timing (change time). FIG. 14 shows the structure of a signal for notifying the signal transmission rate and the change timing.

First, a change code 150, which means a notification signal for changing the signal transmission rate, is transmitted in the downlink signal, and then the changed signal transmission rate ra.
Information 151 (here, 4 bits) indicating te is transmitted. Next, information 152 (here, 8 bits) indicating the transmission rate change timing is transmitted. The transmission rate change timing 152 indicates how many bits are transmitted from the change code 150 before the signal transmission rate is changed.

With the above method, the base station can notify the downlink signal transmission rate and the change timing.

Next, a radio communication system according to the 14th embodiment of the present invention will be described with reference to FIG. Figure 15 shows
28 shows a sequence between the base station and the portable electronic device in the fourteenth embodiment.

A known symbol 160 is inserted in the downlink signal transmitted from the base station to the portable electronic device in order to estimate the downlink transmission path characteristic. The portable electronic device estimates the transmission path characteristic based on the known signal 160 and determines whether to change the downlink signal transmission rate. At the same time as the transmission channel estimation, the portable electronic device demodulates the received wave sent from the base station to obtain information. When changing the downlink signal transmission rate, a transmission rate change request 161 is output to the base station. In the example shown in FIG. 15, the transmission rate change request 161 is output, and at the same time, the received signal transmission rate is switched. Therefore, the received wave cannot be demodulated until the portable electronic device is transmitted from the base station at the same transmission rate as the signal transmission rate being received. In the base station, in response to the transmission rate change request 161,
The downlink signal transmission rate is changed (162). The portable electronic device receives the downlink signal whose signal transmission rate has been changed, and restarts demodulation of the received signal (163).

The above sequence makes it possible to change the downlink signal transmission rate. In the fourth embodiment, the timing at which the base station changes the downlink signal transmission rate is transmitted to the portable electronic device for switching. In the fourteenth embodiment, since the signal transmission speed change request from the portable electronic device is immediately switched,
It becomes possible to follow fast transmission line fluctuations.

When the portable electronic device changes the transmission speed of the received wave at the same time as the request for changing the signal transmission speed as in the fourteenth embodiment, if the change request is not transmitted to the base station due to a code error, Since the signal transmission rate at the time of reception by the portable electronic device and the signal transmission rate at the time of transmission of the base station are different, it becomes impossible to perform downlink communication. To avoid this, the following method is effective.

The first is a method in which the portable electronic device monitors the signal from the base station for a certain period of time after transmitting the request for changing the signal transmission rate, and restores the original transmission rate if the signal cannot be received. The second is a method in which the portable electronic device includes two or more demodulation units so that the portable electronic device can receive two or more different signal transmission rates.

The first method has a drawback that the transmission quality is not improved because the signal transmission speed before the change request is returned again after a certain time after the portable electronic device outputs the signal transmission speed change request. In order to solve this, a method of notifying the signal transmission rate by a control channel is adopted. That is, the above problem is solved by informing the portable electronic device of the transmission rate of the signal transmitted from the base station. In the second method, two or more demodulation units must be provided, which makes it difficult to realize miniaturization of the portable electronic device. However, with the above configuration, it is possible to improve the transmission quality.

As described in detail above, in the communication system in which the uplink transmission rate and the downlink transmission rate are asymmetric, the downlink transmission rate is changed according to the propagation situation between the base station and the portable electronic device. Can be done. This makes it possible to secure downlink transmission quality.

If the portable electronic device is provided with only the circuit for estimating the transmission path condition, it becomes possible for the base station to grasp the propagation condition, and to realize the variable transmission rate even in an access method other than TDMA / TDD. Is possible. Furthermore, if the portable electronic device is provided with a circuit that makes a determination to change the transmission rate, it is not necessary to report the downlink propagation status to the base station, and therefore the uplink transmission amount can be reduced. Throughput can be improved.

Further, according to the present invention in which the downlink transmission rate is changed for each predetermined period and the optimum transmission rate is obtained, the circuit for estimating the transmission path condition can be simplified. Further, it becomes possible to shorten the time required to obtain the optimum transmission rate.

Further, it is possible to solve the problem of reduction in uplink transmission capacity, which occurs when the uplink transmission rate is lower than the downlink transmission rate. Furthermore, it is possible to reduce useless wireless transmission that cannot be received by the portable electronic device.

Also, in a multimedia service for transmitting signals of a plurality of information sources having different system clocks, it becomes possible to multiplex information having different system clocks. Furthermore, by notifying the timing of switching the downlink transmission rate and the changed transmission rate,
It is possible to easily change the transmission speed in the portable electronic device.

Next, a wireless communication system for performing communication using error correction codes in order to secure high transmission quality and enhance reliability of information communication will be described. In the following, while ensuring high transmission quality by using an error correction code, power consumption is reduced to enable a simple portable electronic device configuration, and the overall transmission efficiency is improved.

A wireless communication system according to the fifteenth embodiment of the present invention will be described. FIG. 16 is a block diagram showing a configuration of an error correction device provided in a mobile electronic device in a wireless communication system including a base station and a mobile electronic device.

The error correction device in the portable electronic device is a receiving antenna 201 for receiving a radio signal transmitted from a base station (not shown) to the portable electronic device, and a receiving device for converting the radio signal into a data signal (symbol string). 202, a transmission quality estimation device 203 that estimates the transmission quality of the transmission path between the base station and the portable electronic device, and a switch control device 204 that performs switching control of the switches 205a and 205b according to the estimation result by the transmission quality estimation device 203. , The path of the data signal output from the receiving device 202, the redundancy removing device 206
Alternatively, the switches 205a and 205b for switching to either the error correction decoding device 207, the redundancy removing device 206 for removing a redundant portion (error correction code) for error correction in the data signal, and error correction decoding for the data signal. It comprises an error correction decoding device 207 for performing, and a processing device 208 for performing various processes on data signals.

In the fifteenth embodiment, the signal transmitted from the base station is made up of a symbol string which is error correction coded using a code which can obtain an information sequence only by removing redundancy. Errors can occur in the wireless transmission path from the base station to the portable electronic device. The transmission quality estimation device 203
Estimating the transmission quality of the transmission path, whether the symbol string is processed by the error correction device by the switch control device 204,
Controls what is processed by the redundancy remover. Normally, in order to ensure high transmission quality, as shown in FIG.
Switching to the 7 side, the data signal is processed by the error correction device.

In FIG. 16, the receiver 202 is drawn as if it receives radio waves, but a transmission medium other than radio waves may be used.

FIG. 17 shows the configuration of the transmission quality estimation device 203 in the fifteenth embodiment of the invention. In general, accurate measurement of transmission quality is difficult and costly. For this reason, the transmission quality estimation device 203 uses the measurement result of the physical phenomenon highly correlated with the transmission quality, that is, (1) received electric field strength, (2) eye pattern dispersion, and (3) for simplification of transmission quality estimation. ) The transmission quality is estimated by detecting a known pattern (unique word (known information)), (4) error rate after reception, (5) other, or by combining them, and the switch controller 204 is switched. Instruct switching control.

The measurement of (1) the received electric field strength and (2) the transmission quality by the eye pattern are carried out, for example, by inputting data relating to each from the receiving device 202.
Further, (3) the measurement of the transmission quality based on the known pattern (unique word (known information)) is performed, for example, as shown in the fourth and fifth embodiments. That is, a known pattern for estimating the transmission quality of the transmission path is inserted in the downlink signal transmitted from the base station, and this known pattern is detected. Note that FIG. 16 does not show a known signal detection unit for detecting a known pattern.
(4) The measurement of the transmission quality based on the post-reception error rate is performed by, for example, redundancy removal by the redundancy removal device 206 or error detection after error correction by the error correction decoding device 207.

Here, the transmission quality measuring device 203
It is assumed that the switch switching control is instructed based on the bit error rate obtained by (3) the known pattern and (4) the error rate after reception. In this case, the determination based on the bit error rate is performed in two steps, before the error correction and after the error correction. The transmission quality measuring device 203 compares a preset threshold value (reference quality) with the bit error rate. As a result, when the bit error rate is larger than the threshold value, the switch control device 204 is notified. In contrast, switch 2
It is instructed to switch 05a and 205b to the error correction decoding device 207 side. Further, as a result of the comparison, when the bit error rate is equal to or less than the threshold value, the transmission quality measuring device 203 instructs the switch control device 204 to switch 2
05a and 205b are instructed to be switched to the redundancy removing device 206 side. At this time, the threshold value for the bit error rate is set in two stages in consideration of the coding gain. That is, since the bit error rate is naturally low in the judgment after the error correction, the threshold value is set accordingly.

For example, assuming that the power consumption required for the operation of the redundancy removing apparatus 206 is sufficiently smaller than the power consumption required for the operation of the error correction decoding apparatus 207, the bit and error rate in the transmission quality measuring apparatus 203 are set. As a result of comparison with the threshold value, if the frequency of exceeding the threshold value is half,
The power consumption required for decoding is reduced by half. Therefore, the power consumption of the electronic portable device is reduced, and the configuration can be simplified.

18 to 20 show an algorithm for determining the operation of the error correction device based on the estimated value of the transmission path quality in the fifteenth embodiment. As shown in FIG. 18, as a result of comparing the estimated value (xt) of the transmission quality at the time t obtained by the transmission quality estimation device 203 with the threshold value (reference quality), xt is equal to or less than the threshold value. In such a case, since error correction is redundant, error correction is stopped and power consumption is reduced. Also, x
If t exceeds the threshold, error correction is activated to ensure high transmission quality. In the algorithm shown in FIG. 19, an inertial term is further added to the algorithm shown in FIG. 18 and the estimated value of the past n times is also referred to so as to improve the accuracy of the estimated value of the transmission quality. The algorithm shown in FIG. 20 makes it possible to reduce the storage amount of past estimated values by making the inertia terms have a power exponential relationship.

21 and 22 show an example of the structure of a concatenated code when the concatenated code is used to measure the error rate after reception in the fifteenth embodiment.

In the configuration shown in FIG. 21, information bit 210
On the other hand, redundancy including an error detection code CRC (211) and an error correction code ECC (212) is added. The information bit 210 includes an error detection code CRC (21
After being encoded according to 1), it is subjected to error correction encoding. The post-reception error rate is estimated by error detection after error correction or redundancy removal. However, in this case, the error contained in the redundant portion is not detected. In addition to the configuration shown in FIG. 21, a code that can simultaneously perform error detection and error correction instead of the error detection code, for example, BCH
By using the code or the like, it becomes possible to enhance the error correction capability when the error correction device is operating. The systematic code, Invertible, is a code that can easily extract an information sequence from a codeword without error correction.
There are codes, QLI codes and the like.

In the configuration shown in FIG. 22, information bit 213
On the other hand, redundancy including an error correction code ECC (214) and an error detection code CRC (215) is added. The information bit 213 is an error correction code ECC (21
4) error correction code CRC after error correction by
It is encoded by (215). In the estimation of the error rate after reception, error detection is first performed by the error detection code CRC (215). After that, redundancy removal or error correction can be performed. By using a code capable of performing error detection and error correction at the same time, such as a BCH code, instead of the error detection code CRC, it is possible to enhance the error correction capability when the error correction device is operating.

FIG. 23 shows another configuration example of the error correction device in the fifteenth embodiment. In FIG. 23, a code using the syndrome is used as the error correction decoding. When the code using the syndrome is used, the decoding is performed by the syndrome calculation device 221 and the error pattern generation device 225.
It is performed in two steps, and it is possible to detect whether or not the codeword includes an error by the syndrome. By using the syndrome calculation as an error detection mechanism, the error rate after reception can be used for estimating the transmission quality. According to this configuration, since there is no additional error detection mechanism, the circuit scale is saved.

Next, the sixteenth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 24 is a block diagram showing the structure of the error correction device in the sixteenth embodiment. The same parts as those of the error correction device of the sixteenth embodiment shown in FIG. 16 are designated by the same reference numerals and the description thereof will be omitted.

Besides the control by the transmission quality estimation device 203 using the transmission quality information, there is a means for controlling the error correction capability. For example, if you are using an electronic mobile terminal and the remaining power of the terminal is running low, you can tolerate errors, so in the situation where you want to get the information to the end,
Power consumption can be reduced by forcibly preventing error correction decoding from being performed by external control. Further, the error tolerance can be controlled according to the degree of importance of the information being communicated according to an instruction from the user. It is also possible to consider controlling by the upper layer of the OSI layer.

Next, the seventeenth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 25 is a block diagram showing the structure of the error correction device in the seventeenth embodiment. The same parts as those of the error correction device of the sixteenth embodiment shown in FIG. 16 are designated by the same reference numerals and the description thereof will be omitted.

Even if error correction is not performed by the error correction decoding device 207, the error detection device 22 is performed before redundancy removal.
It is possible to guarantee the reliability of information by performing error detection by means of 8 and performing retransmission control according to the result. The error detection signal is transmitted to the upper layer (processor 208 in FIG. 25). The processing device 208 controls the electronic portable device to request the base station to retransmit the information.

By using, for example, a code that can perform both error correction and error detection, for example, a BCH code, such a mechanism can be realized without reducing the transmission rate.

Next, the eighteenth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 26 is a block diagram showing the structure of the error correction device in the eighteenth embodiment. The same parts as those of the error correction device of the sixteenth embodiment shown in FIG. 16 are designated by the same reference numerals and the description thereof will be omitted. The error correction device shown in FIG. 26 is provided with a plurality of error correction devices 233-1 to 233-n having different capabilities.

When the multimedia service is realized by the downlink from the base station, the information transmitted from the base station to the portable electronic device has several forms,
For example, there are various types such as voice and images. In the electronic portable device, the switch control device 230 functions to select the most suitable error correction device from the plurality of error correction devices 233-1 to 233-n according to the form of the transmitted information. On the electronic portable device side, it is necessary to know which form of information is being sent. This is indicated by information that is already known or is added to the transmitted information in the form of a header or the like. You can The switch control device 230 determines the form of information to be transmitted, and switches the switches 231a and 231b so that error correction is performed by the corresponding error correction decoding device. As a result, for example, in the case of voice or the like, the degree of error correction is changed according to the importance of hearing in accordance with human auditory characteristics, or in image transmission, the DC component after orthogonal transformation is performed. Error correction coding with high capability because important information is included and error correction with low capability for the AC component to increase the rate, etc. Can be selected.

Next, the nineteenth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 27 is a block diagram showing the configuration of the wireless communication system using the error correction device according to the nineteenth embodiment.

The receiving station (electronic form device) estimates the quality of the transmission path by the transmission quality estimating device 243, controls the execution of error correction by the error correction decoding device 246 according to the estimation result, and transmits the signal to the transmitting station (base station). ), The operation of the error correction device is controlled.

If it is determined that the transmission quality is inferior to the reference quality, error correction is not performed, and if it is determined that the reference quality is satisfied, error correction is performed.

FIG. 28 shows an example of negotiation between the transmitting station and the receiving station in the wireless communication system of the nineteenth embodiment. The receiving station that has detected the deterioration of the transmission quality determines the use of the error decoding / correcting apparatus 246, and transmits a notification of the deterioration of the transmission quality for prompting the transmitting station to use the error correcting / decoding apparatus 246. The transmitting station receives the notification of the deterioration of the transmission quality and activates the error correction coding device 256 to cause the error correction coding device 256 to operate.
Notify the receiving station that the has been activated. The receiving station, which has received the notification, knows that the received signal is error-correction-coded, and thus switches the switches 245a and 245b by the transmission quality estimation device 243 to operate the error-correction decoding device 246.

After detecting the deterioration of the transmission path quality,
It can be determined that the information received during the period until the error correction decoding device 246 operates is significantly unreliable. Therefore,
The reliability can be improved by discarding the information in this period.

Further, the receiving station which has detected that the transmission path quality has been improved notifies the transmitting station that the error correction decoding device 246 is not used. The transmitting station that has received the notification stops the operation of the error correction coding device 256 and notifies the receiving station side that the operation has stopped. The receiving station that has received the notification is the error correction decoding device 2
The operation of 46 is stopped.

FIG. 29 shows the improvement of the transmission rate in the communication system using the error correction device of the nineteenth embodiment by not performing the coding. When the error correction device is not operating, the code length is shortened and the transmission rate is increased by not transmitting the redundant portion due to the error correction coding.

FIG. 30 shows the improvement of the transmission rate when information is embedded in the redundant part by error correction coding in the communication system using the error correction device of the twentieth embodiment.
When the error correction device is not operating, the transmission rate is increased by embedding information bits in place of the redundant part by error correction coding.

FIG. 31 is a block diagram showing the structure of a communication system using the error correction device according to the 21st embodiment. The error correction device in the twenty-first embodiment includes a plurality of error correction decoding devices 255-1 and 255-2 according to the difference in transmission quality.
55-n are provided.

For example, there are a code A for high error rate and a code B for low error rate, and an error correction decoding device corresponding to each is provided. Normally, the code B is used, and when the error is expected to be high, the code is switched to the code A. When the error rate is low and it is expected that almost no error will occur, the code B is coded. , The error correction is not performed or the encoding itself is stopped.

Also, the suitable code is different between the transmission line with many bursty errors and the transmission line with many random errors.
In this case, the transmission quality estimation device needs to identify the type of error.

The portable electronic device selects and uses the corresponding error correction decoding device from the plurality of error correction decoding devices 255-1 to 255-n according to the switching of the code. According to the transmission quality estimation result by the transmission quality estimation device 203,
By selecting an error correction decoding device, optimum control of power consumption is performed while maintaining certain reliability. A redundancy removing device may be included in the decoding device. Also, an error correction device suitable for the required reliability can be selected.

FIG. 32 is a block diagram showing the structure of a communication system using the error correction device according to the 22nd embodiment. The error correction device of the 22nd embodiment is the same as the base station 260.
Improve accuracy of transmission quality estimation by communicating and cooperating with. For example, the base station 260 may be sent a measurement result of a physical phenomenon having a high correlation with a transmission quality such as a received electric field strength, and the base station 260 may be made to perform a complicated calculation, and the result may be sent back. The switch control device 227 controls the switches 205a and 205b. Moreover, since the base station 260 can obtain a wider range of information, it is possible to improve the accuracy of estimation regarding the transmission quality. Also, the base station 260 uses the database 261 for the relationship between the place, time, etc. and the transmission quality.
You can use past results by using etc. For example, when the same transmission line is used for transmission and reception such as TDD in wireless communication, the transmission quality can be reduced by having a part of the quality measurement of the transmission line (such as the effect of shadowing on the transmission line) undertaken. The estimation device 271 can be simplified.

As described above in detail, by using the error correction device of the present invention, the error correction capability is adaptively controlled, so that the reliability of information can be guaranteed and the power consumption can be saved. A portable electronic device having various configurations can be provided.

Further, not only the error correction device is used independently, but also it is incorporated as a part of the radio communication system, so that it is possible to further enhance the effect in terms of power consumption and communication efficiency.

[0170]

As described in detail above, according to the present invention, errors occurring in signals transmitted from a base station to a portable electronic device are reduced, and high downlink transmission quality is ensured regardless of the presence or absence of multipath. At the same time, it is possible to improve the overall transmission efficiency and further simplify the configuration of the portable electronic device.

Further, it becomes possible to secure a high transmission quality by using the error correction code, reduce the power consumption, enable the construction of a simple portable electronic device, and improve the overall transmission efficiency.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a data communication system using a wireless communication system according to the present invention.

FIG. 2 is a diagram showing configurations of a base station and a mobile electronic device according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a mobile electronic device according to a second exemplary embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a mobile electronic device according to a third exemplary embodiment of the present invention.

FIG. 5 is a diagram showing a protocol between a base station and a mobile electronic device according to a fourth embodiment of the present invention.

FIG. 6 is a diagram showing a protocol between a base station and a mobile electronic device according to a fifth embodiment of the present invention.

FIG. 7 is a flowchart showing a procedure of changing a downlink transmission rate in a base station according to a sixth embodiment of the present invention.

FIG. 8 is a diagram showing downlink and uplink signals according to a seventh embodiment of the present invention.

FIG. 9 is a diagram showing downlink and uplink signals according to an eighth embodiment of the present invention.

FIG. 10 is a diagram showing an uplink signal according to a ninth embodiment of the present invention.

FIG. 11 is a diagram showing a table of predetermined downlink transmission rates and codes according to the tenth embodiment of the present invention.

FIG. 12 is a diagram showing a configuration of a mobile electronic device according to an eleventh embodiment of the present invention.

FIG. 13 is a diagram showing a signal generation method for detecting a transmission error according to a twelfth embodiment of the present invention.

FIG. 14 is a diagram showing a configuration of a signal for notifying a change of a downlink transmission rate and a change timing transmitted from a base station to a portable electronic device according to a thirteenth embodiment of the present invention.

FIG. 15 is a diagram showing a protocol between a base station and a mobile electronic device according to a fourteenth embodiment of the present invention.

FIG. 16 is a block diagram showing the configuration of an error correction device provided in a mobile electronic device of a wireless communication system according to a fifteenth embodiment of the present invention.

FIG. 17 is a diagram showing the configuration of a transmission quality estimation device in a fifteenth embodiment of the present invention.

FIG. 18 is a diagram showing an algorithm for determining the operation of the error correction device based on the estimated value of the transmission path quality in the fifteenth embodiment of the present invention.

FIG. 19 is a diagram showing an algorithm for determining the operation of the error correction device based on the estimated value of the transmission path quality in the fifteenth embodiment of the present invention.

FIG. 20 is a diagram showing an algorithm for determining the operation of the error correction device based on the estimated value of the transmission path quality in the fifteenth embodiment of the present invention.

FIG. 21 is a diagram showing a configuration example of a concatenated code when the concatenated code is used to measure the error rate after reception in the fifteenth embodiment of the present invention.

FIG. 22 is a diagram showing a configuration example of a concatenated code when the concatenated code is used to measure the error rate after reception in the fifteenth embodiment of the present invention.

FIG. 23 is a block diagram showing another configuration example of the error correction device according to the fifteenth embodiment of the present invention.

FIG. 24 is a block diagram showing the structure of an error correction device according to a sixteenth embodiment of the present invention.

FIG. 25 is a block diagram showing the configuration of an error correction device in a seventeenth embodiment of the present invention.

FIG. 26 is a block diagram showing the structure of an error correction device according to an eighteenth embodiment of the present invention.

FIG. 27 is a block diagram showing the configuration of a wireless communication system using an error correction device according to a nineteenth embodiment of the present invention.

FIG. 28 is a diagram for explaining an example of negotiation between a transmitting station and a receiving station in the wireless communication system according to the nineteenth embodiment of the present invention.

FIG. 29 is a diagram for explaining the improvement of the transmission rate in the communication system using the error correction device according to the 19th embodiment of the present invention.

FIG. 30 is a diagram for explaining the improvement of the transmission rate in the communication system using the error correction device according to the twentieth embodiment of the present invention.

FIG. 31 is a block diagram showing the configuration of a communication system using an error correction device according to a 21st embodiment of the present invention.

FIG. 32 is a block diagram showing the configuration of a communication system using an error correction device according to a 22nd embodiment of the present invention.

FIG. 33 is a diagram for explaining selection of modulation parameters in a conventional wireless communication system.

[Explanation of symbols]

000 ... base station, 002,009,010,017 ... antenna, 033,001,011,016 ... RF section, 0
04, 012 ... Demodulation section, 005 ... Transmission rate change request signal detection section, 006 ... Control section, 007, 015, 22 ... Modulation section, 001 ... Portable electronic device, 013 ... Propagation path estimation section, 0
14 ... Control unit, 10 ... Portable electronic device, 11, 201 ... Receiving antenna, 12 ... Receiving RF unit 12, 13, 24 ... Variable frequency oscillator, 14, 25 ... Mixer, 15, 23 ... Low pass filter, 16 ... Demodulating unit , 17 ... Known signal detector,
18 ... Correlator, 19 ... Memory, 20 ... Transmission path estimation data creation unit, 21 ... Control unit, 26 ... Transmission RF unit, 27 ... Transmission antenna, 30 ... Radio propagation status determination circuit, 31 ... Transmission rate change request data creation Part, 33 ... Received electric field strength detection part,
202 ... Receiving device, 203 ... Transmission quality estimating device, 205
a, 205b, 231a, 231b ... Switch, 20
4, 224 ... Switch control device, 206 ... Redundancy removal device, 207, 233-1-233-n, 255-1-2
55-n ... Error correction decoding device, 208 ... Processing device, 22
1 ... Syndrome calculation device, 225 ... Error pattern generation device, 228 ... Error detection device, 256 ... Error correction coding device, 261 ... Database.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuyasu Nakajima No.1 Komukai Toshiba Town, Komukai-ku, Kawasaki City, Kanagawa Prefecture, Toshiba Research and Development Center, Ltd. Muko Toshiba Town No. 1 Incorporated company Toshiba Research and Development Center (72) Inventor Hideo Shimizu No. 1 Komukai Toshiba Town, Kawasaki City Kanagawa Prefecture Komukai Toshiba R & D Center (72) Inventor Shinichi Kawamura Kanagawa Prefecture No. 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi Incorporated company Toshiba Research and Development Center

Claims (8)

[Claims] 1. A portable electronic device comprising a wireless device, a downlink line for transmitting a signal to the portable electronic device, and a signal for the downlink line for receiving a signal from the portable electronic device. In a wireless communication system including a wireless transmission system including a base station that wirelessly communicates with the electronic portable device via an uplink line having a signal transmission speed lower than the transmission speed, the base station is a downlink transmission speed. A wireless communication system comprising: a transmission rate changing means for changing the transmission rate. 2. The portable electronic device, based on a radio signal transmitted from the base station to the portable electronic device,
Estimating means for estimating the radio propagation situation with the base station, the base station, based on the radio propagation situation obtained by the estimating means, determines the transmission rate of the downlink,
The wireless communication system according to claim 1, wherein the transmission rate changing means changes the transmission rate of the downlink. 3. The portable electronic device, based on a radio signal transmitted from the base station to the portable electronic device,
The base station includes: an estimating unit that estimates a radio propagation condition with the base station; and a determining unit that determines a downlink transmission rate from the radio propagation condition obtained by the estimating unit; The wireless communication system according to claim 1, wherein a request for changing the downlink to the transmission rate determined by the determining means is transmitted by a wireless signal. 4. The base station changes the transmission rate of the downlink for each predetermined period, and the portable electronic device determines whether or not reception at the transmission rate is correct. 2. The wireless communication system according to claim 1, wherein the base station is notified of a maximum receivable transmission rate among the changed transmission rates, and the downlink transmission rate is determined. 5. The downlink transmission rate is previously set.
It is determined discretely between the base station and the portable electronic device, and the portable electronic device detects an error in a transmission error condition of a radio signal transmitted from the base station to the portable electronic device. Detecting means, and means for determining the transmission rate of the downlink according to the transmission error status obtained from the error detecting means, the portable electronic device, according to the determined transmission rate of the downlink, 2. The wireless communication system according to claim 1, wherein the base station requests the base station to change the transmission rate. 6. The wireless communication system according to claim 1, wherein the base station periodically inserts a known signal for channel estimation into a wireless signal for the portable electronic device. 7. A portable electronic device comprising a wireless device, a downlink line for transmitting a signal to the portable electronic device and a signal for the downlink line for receiving a signal from the portable electronic device. In a wireless communication system including a wireless transmission system including a base station that wirelessly communicates with the electronic portable device via an uplink line having a signal transmission speed lower than the transmission speed, the base station is a portable electronic device. The portable electronic device includes an error correction encoding device that encodes using a code to which a redundant signal for correcting an error in an information signal to be transmitted is added, wherein the portable electronic device encodes a wireless signal transmitted from a base station. A receiving device for converting into an error correction decoding device for decoding the coded sequence obtained by the receiving device and performing error correction; and a coded sequence obtained by the receiving device. A redundancy removing device that removes a redundant signal and outputs an information signal, a transmission quality estimating device that estimates the transmission quality of a transmission path on which a wireless signal received by the receiving device is transmitted, and an estimation by the transmission quality estimating device If the determined transmission quality is inferior to the reference quality, the symbol string is processed by the error correction decoding device, and if it is determined that the transmission quality satisfies the reference quality, the redundancy removing device is processed. A wireless communication system comprising an error correction device configured by switching means for switching to processing. 8. A portable electronic device comprising a wireless device, a downlink line for transmitting a signal to the portable electronic device and a signal for the downlink line for receiving a signal from the portable electronic device. In a wireless communication system including a wireless transmission system including a base station that wirelessly communicates with the electronic portable device via an uplink line having a signal transmission speed lower than the transmission speed, the base station is the portable electronic device. An error correction coding device for error correction coding a wireless signal to be transmitted to the portable electronic device, wherein the portable electronic device is an error correction decoding device for error correcting decoding the error correction coded wireless signal, and the wireless signal is transmitted. A transmission path quality estimation device for estimating the transmission path quality of the transmission path, and the transmission quality estimation device of the portable electronic device determines that the transmission quality is lower than the reference quality. If it is determined that the error-correction coding apparatus transmits the error-correction-encoded radio signal and the error-correction decoding apparatus performs decoding, and it is determined that the transmission quality satisfies the reference quality, A communication system characterized by stopping the error correction decoding device without performing error correction encoding.