JP4552732B2 - Wireless receiving apparatus and transmission / reception mode determination method - Google Patents

Description

  The present invention relates to a radio reception apparatus and a transmission / reception mode determination method, and more particularly to a radio reception apparatus and a transmission / reception mode determination method capable of dynamically maintaining reception throughput in an optimum state according to a surrounding state.

  A best effort type packet communication service has been proposed like EGPRS (Enhanced General Packet Radio Services) standardized by ETSI (European Telecommunications Standard Institute). In this type of service, of course, since the reception quality changes depending on the distance from the base station or the surrounding environment, it is necessary to perform error correction processing by giving redundancy to the data. On the other hand, there is also a request from the user to receive a service at a slightly higher transmission rate.

  For example, in Japanese Patent Laid-Open No. 5-300128, in a configuration including a transmission device and a reception device connected by a wireless line, a plurality of encoders having different error correction capabilities on the transmission device side, an encoder selector, The receiver also includes a plurality of decoders having different error correction capabilities and a decoder selector. The receiver evaluates the signal quality of the received signal, and the evaluation result is transmitted to the transmitter. The configuration that feeds back is introduced.

JP-A-5-300128

  However, in the case of a so-called best effort service in which the transmission / reception mode can be changed depending on the channel condition, the maximum throughput can be realized if the specification dynamically changes a plurality of modulation schemes as in the above-described EGPRS, for example. There is a problem that the area and conditions are very limited. Moreover, even when the communication channel is in a good state, it is difficult to intentionally change to a transmission / reception mode with a low error correction capability, which also leads to a decrease in throughput.

  Also, as disclosed in Patent Document 1, a method of changing the encoding method on the mobile station side according to the signal quality of the received signal has been proposed, but there is a problem that it is difficult to evaluate the signal quality of the received channel. For example, in the method of simply comparing the reception channel with the threshold value, even if the same evaluation is made, the transmission / reception mode can be aimed at a transmission / reception mode with a lower error correction capability based on the performance of the mobile station device and the surrounding environment. Conversely, there may be a case where the transmission / reception mode should be changed to a transmission / reception mode with higher error correction capability.

  The present invention has been made in view of the above-described circumstances, and the object of the present invention is to evaluate the surrounding environment using a simple and accurate signal quality evaluation standard and maintain the reception throughput in an optimum state. It is an object of the present invention to provide a wireless reception device and a transmission / reception mode determination method that can be used.

  According to a first aspect of the present invention, an antenna that receives data from a wireless transmission station that transmits data that has been encoded by selecting one of a plurality of transmission / reception modes with different error correction redundancy, A radio unit for measuring the quality of radio waves received from the radio transmitting station, a decoding device for selecting any one of the transmission / reception modes and decoding received data, an upper threshold and a lower threshold for communication quality Value and a storage unit storing the relationship between the communication quality and the transmission / reception mode to be selected so that the transmission / reception mode having a low error correction redundancy is selected as the communication quality is improved, and the radio wave received from the wireless transmission station There is provided a wireless reception device including a control device that selects an optimal transmission / reception mode according to communication quality and requests the wireless transmission station to change.

  More specifically, (A) When the communication quality of the measured reception channel exceeds the upper threshold value, the control unit selects a transmission / reception mode having a lower error correction redundancy than the current transmission / reception mode. And (B) if the communication quality of the measured reception channel is below the lower threshold, select a transmission / reception mode with higher error correction redundancy than the current transmission / reception mode, and (C) the measurement If the communication quality of the reception channel is between the upper threshold value and the lower threshold value, further measure the communication quality of the channel adjacent to the reception channel, and refer to the storage unit Select a transmission / reception mode according to the communication quality of the channel. According to the above criteria, even if the communication quality is within the range of the upper and lower thresholds, the transmission / reception mode is changed more finely. Regardless, a configuration for changing the transmission / reception mode can be obtained.

  According to the second aspect of the present invention, there is provided a method for determining a transmission / reception mode that can be implemented using the above-described wireless reception apparatus.

  According to the present invention, it is possible to actively determine the transmission / reception mode from the state of the reception channel or the adjacent channel, and as a result, a configuration for optimizing the reception throughput can be obtained.

  Next, the best mode for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a mobile phone according to an embodiment of the present invention. Referring to FIG. 1, a cellular phone including an antenna 1, a radio unit 2, a decoding device 3, a control device 4, and a database 5 is shown.

  The antenna 1 is means for receiving electromagnetic waves from a radio base station (not shown), and the radio unit 2 sends data received by the antenna 1 to the decoding device 3 and sends an electric field strength signal to the control device 4.

  The decoding device 3 is means for performing a decoding operation on received data according to an instruction from the control device 4. The control device 4 collates the electric field strength signal received from the wireless unit 2 with the contents of the database 5 and determines the operation state (transmission / reception mode) of the decoding device 3.

  The database 5 stores and holds the relationship between the upper threshold value (UL), the lower threshold value (LL), the electric field strength of the adjacent channel, and the transmission / reception mode to be selected. FIG. 2 shows an example of this, and a transmission / reception mode with low error correction redundancy is selected as the electric field strength increases. In the example of FIG. 2, a transmission / reception mode by MCS (Modulation Coding Scheme) of EGPRS or EDGE standard modulation coding scheme is defined. If the electric field strength of the adjacent channel is on the order of −90 dBm, MCS2 is selected.

  The configurations of the antenna 1, the radio unit 2, the control device 4, and the database 5 are well known to those skilled in the art and are not directly related to the present invention. The decoding device 3 can also use a signal processor known as a DSP (Digital Signal Processor).

  Next, the operation of the present embodiment will be described in detail with reference to the drawings. FIG. 3 is a flowchart showing the transmission / reception mode changing process applied to the mobile phone according to the present embodiment. Referring to FIG. 3, first, the wireless unit 2 measures the electric field strength X of the reception channel and transmits it to the control device 4 (step S001).

  The control device 4 that has received the electric field strength X compares the electric field strength X with the upper threshold value (UL) (step S002). Here, for example, when the electric field intensity X exceeds the upper threshold value (UL), the control device 4 determines that the reception quality is good, and the current operating condition (transmission / reception mode) of the decoding device 3 is more erroneous. The transmission / reception mode is switched to a method with a higher correction capability (higher throughput) (step S003). For example, a process of increasing the MCS number of the EGPRS or EDGE standard modulation and coding scheme by one to several stages is performed.

  Subsequently, the control device 4 compares the electric field strength X with the lower threshold value (LL) (step S004). Here, for example, when the electric field strength X is lower than the lower threshold value (LL), the control device 4 determines that the reception quality is bad, and the current operating condition (transmission / reception mode) of the decoding device 3 is more The transmission / reception mode is switched so as to be lowered by one step to a method with high error correction capability (throughput is reduced) (step S004). Therefore, even when the line state is bad, the transmission / reception mode is changed in the direction in which the call is maintained without being disconnected immediately. This corresponds to, for example, a process of reducing the MCS number of the EGPRS or EDGE standard modulation and coding scheme by one to several stages.

  When the electric field intensity X of the reception channel is between the upper and lower thresholds (UL> X> LL), the control device 4 determines the electric field intensity of the channel adjacent to the reception channel (adjacent channel) in the radio unit 2. Instruct to confirm. The control device 4 that has received the electric field strength of the adjacent channel from the radio unit 2 searches the database 5 and selects a transmission / reception mode corresponding to the electric field strength (step S006).

  As described above, the control device 4 estimates the current field state, determines whether error correction should be strengthened or weakened, and feeds back to the transmitting station device. Further, the decoding device 3 changes the operation condition (transmission / reception mode) in accordance with the instruction of the control device 4.

  In this way, it is possible to actively determine the operating condition (transmission / reception mode) from the state of the reception channel or the peripheral channel, and improve the throughput. For example, −60 dBm is set as the upper threshold value (UL), −90 dBm is set as the lower threshold value (LL), and a table as shown in FIG. 2 is set to select the transmission / reception mode by the adjacent channel. If the electric field strength of the reception channel is −50 dBm (X> UL), processing for switching to a transmission / reception mode with higher throughput is performed, and if the electric field strength of the reception channel is −100 dBm (X < LL), a process of switching to a transmission / reception mode with higher error correction capability is performed.

  Similarly, if the electric field strength of the receiving channel is −70 dBm (UL> X> LL), the throughput is changed according to the electric field strength of the adjacent channel using the table illustrated in FIG. . For example, if the state of the adjacent channel is good, a method with a lower error correction capability (high throughput) is selected, and if the state of the adjacent channel is not good, the error correction capability is higher (throughput becomes lower). The method will be selected. The state of the adjacent channel may propagate to the receiving channel at any time, and even if the receiving channel is in the middle of the upper and lower thresholds and it is difficult to determine either, perform such processing. Thus, the reception throughput can be set to the optimum state at an early stage.

  The example in which the present invention is applied to a general mobile phone system has been described above, but the principle of the present invention can be applied not only to a mobile phone but also to other wireless transmission systems. Similarly, it goes without saying that the present invention is also applicable to a mobile phone system having a plurality of transmission / reception modes having different error correction capabilities other than the EGPRS standard and the EDGE standard.

  In the above-described embodiment, the decoding device 3 has been described as a digital signal processor, but other decoding devices having similar functions can be used. Similarly, in the above-described embodiment, the database 5 is described as storing the upper and lower threshold values of the electric field strength and the electric field strength of the adjacent channel and the corresponding transmission / reception mode. It is also possible to use a parameter representing.

1 is a block diagram illustrating a schematic configuration of a mobile phone according to an embodiment of the present invention. It is a figure showing an example of the table hold | maintained at the database of the mobile telephone which concerns on one Example of this invention. It is a flowchart showing an example of the change process of the transmission / reception mode which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna 2 Radio | wireless part 3 Decoding apparatus 4 Control apparatus 5 Database (memory | storage part)

Claims (4)

An antenna that receives data from a wireless transmission station that transmits data that has been encoded by selecting one of a plurality of transmission / reception modes having different error correction redundancy;
A wireless unit for measuring the quality of radio waves received from the wireless transmission station;
A decoding device that selects one of the transmission / reception modes and decodes the received data;
A memory storing the relationship between the communication quality and the transmission / reception mode to be selected so that the transmission / reception mode having a lower error correction redundancy is selected as the communication quality is improved. And
A control device that requests a change in transmission / reception mode to the wireless transmission station, and a wireless reception device comprising:
The controller is
(A) If the communication quality of the measured reception channel exceeds the upper threshold value, select a transmission / reception mode with lower error correction redundancy than the current transmission / reception mode;
(B) If the communication quality of the measured reception channel is below the lower threshold, select a transmission / reception mode with higher error correction redundancy than the current transmission / reception mode;
(C) When the communication quality of the measured reception channel is between the upper threshold value and the lower threshold value, the communication quality of a channel adjacent to the reception channel is further measured, and the storage unit Selecting a transmission / reception mode according to the communication quality of the adjacent channel with reference to
A wireless receiver characterized by the above. As the communication quality, an electric field strength value is measured,
The storage unit holds a table defining a relationship between a field strength section and a transmission / reception mode to be selected so that a transmission / reception mode with low error correction redundancy is selected as the electric field strength increases;
The wireless reception device according to claim 1. A storage unit for storing the relationship between the communication quality and the transmission / reception mode to be selected so that the transmission / reception mode having a lower error correction redundancy is selected as the communication quality is improved. A method for determining a transmission / reception mode in a wireless reception device comprising:
A step of measuring the communication quality of radio waves received from a radio transmission station that transmits and receives data that has been encoded by selecting any one of a plurality of transmission / reception modes with different error correction redundancy,
When the wireless reception device (A) communication quality of the reception channel exceeds the upper threshold value, the wireless reception device selects a transmission / reception mode having a lower error correction redundancy than the current transmission / reception mode, and (B) If the communication quality is lower than the lower threshold, select a transmission / reception mode with higher error correction redundancy than the current transmission / reception mode, and (C) the communication quality of the reception channel is lower than the upper threshold If it is between the threshold value, the step further measures the communication quality of the channel adjacent to the reception channel, and refers to the storage unit to select the transmission / reception mode according to the communication quality of the adjacent channel When,
The wireless reception device requesting the wireless transmission station to change a transmission / reception mode,
A method for determining a transmission / reception mode. The storage unit holds a table that defines a relationship between a field strength section and a transmission / reception mode to be selected so that a transmission / reception mode with low error correction redundancy is selected as the electric field strength increases.
Using a field strength value as the communication quality, and selecting a transmission / reception mode according to the field strength;
The transmission / reception mode determination method according to claim 3.

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