JP2014207598A - Radio communication system, radio communication method, radio base station device, and radio terminal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely perform mode change by specifying a procedure for performing mode change from a narrow band mode to a wide band mode between a radio base station device and a radio terminal device during communication.SOLUTION: A radio communication system for continuing communication by performing mode change from a narrow band mode having a predetermined frequency band width to a wide band mode having relatively wide frequency band width between a radio base station device and a radio terminal device during the communication having the predetermined frequency band width and a predetermined center frequency comprises: the radio base station device which notifies the radio terminal device of the mode change to the wide band mode; and the radio terminal device which detects an interference level in the frequency band width and at the center frequency of the wide band mode and notifies the radio base station device of the interference level, so that the radio base station device and radio terminal device perform the mode change to the wide band mode when the interference level is equal to or smaller than a specified value.

Description

  The present invention relates to a wireless communication system capable of changing a mode from a narrowband mode in which communication is performed with, for example, a 20 MHz bandwidth to a broadband mode in which communication is performed with, for example, a 40 MHz bandwidth, while the wireless base station device and the wireless terminal device are in communication. The present invention relates to a communication method, a radio base station apparatus, and a radio terminal apparatus.

  IEEE802.11n (Non-patent Document 1), a wireless LAN standard, defines a channel bonding technology that expands the 20 MHz bandwidth to the 40 MHz bandwidth as a means to widen the transmission path in order to increase the communication capacity. Has been. This is a combination of two adjacent 20 MHz channels that are used continuously and unused subcarriers in the guard band located at the boundary of the two 20 MHz channels are also available, substantially more than twice as much. This technology realizes transmission speed. However, a control signal (beacon signal) periodically transmitted between the radio base station apparatus and the radio terminal apparatus is transmitted with a 20 MHz bandwidth and received by each apparatus communicating with the 40 MHz bandwidth or the 20 MHz bandwidth. It is possible.

IEEE Std 802.11 -2012

  Conventionally, when communication is started between a radio terminal apparatus and a radio base station apparatus that can support the narrowband mode and the wideband mode, it is determined whether the communication is performed in the narrowband mode or the wideband mode. On the other hand, for example, when changing the mode from the narrowband mode to the wideband mode between the wireless base station device and the wireless terminal device that are communicating in the narrowband mode, the mode change cannot be unilaterally. A procedure is conceivable.

  First, a radio base station apparatus communicating in a narrowband mode transmits a control signal including mode change information of a frequency bandwidth and a center frequency used in the wideband mode to the radio terminal apparatus in the narrowband mode. The wireless terminal device returns a response signal to the control signal to the wireless base station device, and the wireless base station device and the wireless terminal device simultaneously change from the narrowband mode to the wideband mode, and thereafter perform communication in the wideband mode.

  At this time, as shown in FIG. 3, the radio base station apparatus has no interference in the frequency band of the wideband mode, but the radio terminal apparatus may have an interference signal in the frequency band of the wideband mode. However, since the radio base station apparatus cannot detect interference signals around the radio terminal apparatus, the radio terminal apparatus cannot respond even if the radio base station apparatus transmits a control signal for changing to the broadband mode to the radio terminal apparatus. become. On the other hand, when changing from the wideband mode to the narrowband mode, it is not necessary to consider such an interference problem, and the mode can be changed by notifying the radio terminal device from the radio base station device.

  The present invention provides a radio communication system and a radio communication method capable of defining the procedure for changing the mode from the narrowband mode to the wideband mode between the radio base station apparatus and the radio terminal apparatus in communication and surely changing the mode. An object of the present invention is to provide a radio base station apparatus and a radio terminal apparatus.

  According to a first aspect of the present invention, there is provided a relatively wide frequency bandwidth from a narrowband mode of a predetermined frequency bandwidth between a wireless base station device and a wireless terminal device that are communicating at a predetermined frequency bandwidth and center frequency. In a wireless communication system in which communication is continued after changing the mode to the broadband mode, the wireless base station device notifies the wireless terminal device of the mode change to the broadband mode, and the wireless terminal device notifies the frequency bandwidth of the broadband mode by the notification. In addition, the interference level at the center frequency is detected and notified to the radio base station apparatus, and the radio base station apparatus and the radio terminal apparatus change the mode to the wideband mode when the interference level is equal to or lower than a specified value.

  According to a second aspect of the present invention, there is provided a relatively wide frequency bandwidth from a narrowband mode of a predetermined frequency bandwidth between a wireless base station device and a wireless terminal device that are communicating at a predetermined frequency bandwidth and center frequency. In a radio communication system in which communication is continued after changing the mode to the wideband mode, the radio base station apparatus receives a first control signal including mode change information having a mode change timing, a frequency bandwidth of the wideband mode, and a center frequency. The wireless terminal device includes means for transmitting to the wireless terminal device in the narrowband mode. When the wireless terminal device receives the first control signal, the wireless terminal device detects an interference level in the frequency bandwidth and the center frequency of the wideband mode, and includes an interference detection result. Means for transmitting the second control signal to the radio base station apparatus in the narrowband mode, the radio base station apparatus receives the second control signal, and the interference level is Means for transmitting a third control signal for instructing mode change to the wideband mode at the timing of mode change when the mode is less than or equal to a fixed value, to the radio terminal device in the narrowband mode; When receiving the reception response to the third control signal, the radio base station apparatus returns a reception response and returns a reception response and performs processing for changing from the narrowband mode to the wideband mode. The wireless base station device and the wireless terminal device transmit and receive the fourth control signal and the reception response in the wideband mode and then communicate in the wideband mode after changing to the wideband mode. It is the structure which continues.

  According to a third aspect of the present invention, there is provided a relatively wide frequency bandwidth from a narrowband mode of a predetermined frequency bandwidth between a wireless base station device and a wireless terminal device that are communicating at a predetermined frequency bandwidth and center frequency. In a wireless communication method in which communication is continued after changing the mode to the broadband mode, the wireless base station device notifies the wireless terminal device of the mode change to the broadband mode, and the wireless terminal device notifies the frequency bandwidth of the broadband mode by the notification. Then, the interference level at the center frequency is detected and notified to the radio base station apparatus. When the interference level is equal to or lower than the specified value, the radio base station apparatus and the radio terminal apparatus change the mode to the broadband mode.

  According to a fourth aspect of the present invention, there is provided a relatively wide frequency bandwidth from a narrowband mode of a predetermined frequency bandwidth between a wireless base station device and a wireless terminal device that are communicating at a predetermined frequency bandwidth and center frequency. In the wireless communication method for continuing the communication after changing the mode to the wideband mode, the wireless base station device outputs a first control signal including mode change information having a mode change timing, a frequency bandwidth of the wideband mode, and a center frequency. When the wireless terminal device receives the first control signal, the wireless terminal device detects the interference level at the frequency bandwidth and the center frequency of the wideband mode, and includes the interference detection result. The control signal is transmitted to the radio base station apparatus in the narrowband mode, and the radio base station apparatus receives the second control signal and changes the mode when the interference level is equal to or less than the specified value. A third control signal instructing mode change to the wideband mode at a timing to transmit to the wireless terminal device in the narrowband mode, and upon receiving the third control signal, the wireless terminal device returns a reception response; When the radio base station apparatus receives a reception response to the third control signal, the radio base station apparatus performs a process of changing from the narrowband mode to the wideband mode. After changing to the broadband mode, the terminal device transmits and receives the fourth control signal and reception response in the broadband mode, and then continues communication in the broadband mode.

  According to a fifth aspect of the present invention, there is provided a relatively wide frequency bandwidth from a narrowband mode of a predetermined frequency bandwidth between a wireless base station device and a wireless terminal device that are communicating at a predetermined frequency bandwidth and center frequency. In a radio base station apparatus of a radio communication system that continues communication by changing the mode to the wideband mode, the radio terminal apparatus is notified of the mode change to the wideband mode, and the broadband mode detected by the radio terminal apparatus is detected in response to the notification. When the interference level at the frequency bandwidth and the center frequency is equal to or lower than a specified value, the mode is changed to the wideband mode.

  According to a sixth aspect of the present invention, there is provided a relatively wide frequency bandwidth from a narrowband mode of a predetermined frequency bandwidth between a wireless base station device and a wireless terminal device that are communicating at a predetermined frequency bandwidth and center frequency. In a radio base station apparatus of a radio communication system in which communication is continued after changing the mode to the wideband mode, a first control signal including mode change information having a mode change timing, a frequency bandwidth of the wideband mode, and a center frequency, Means for transmitting to the wireless terminal device in the narrowband mode, and the mode change when the frequency bandwidth of the wideband mode detected by the wireless terminal device with respect to the first control signal and the interference level at the center frequency are below the specified value Means for transmitting a third control signal instructing mode change to the wideband mode at a timing to the wireless terminal apparatus in the narrowband mode, and third control When the reception response transmitted from the wireless terminal device is received in response to the signal, the means for performing processing for changing from the narrowband mode to the broadband mode and the wireless terminal device in the broadband mode after changing to the broadband mode And a means for transmitting and receiving a fourth control signal and a reception response, and thereafter the communication is continued in the broadband mode.

  According to a seventh aspect of the present invention, there is provided a relatively wide frequency bandwidth from a narrowband mode of a predetermined frequency bandwidth between a wireless base station device and a wireless terminal device that are communicating at a predetermined frequency bandwidth and center frequency. In a wireless terminal device of a wireless communication system that continues communication by changing the mode to the broadband mode, when the wireless base station device is notified of the change to the broadband mode, the frequency bandwidth of the broadband mode and the interference level at the center frequency are set. It is configured to detect and notify the radio base station apparatus, and to change the mode to the broadband mode when the interference level is below a specified value.

  According to an eighth aspect of the present invention, there is provided a relatively wide frequency bandwidth from a narrowband mode of a predetermined frequency bandwidth between a wireless base station device and a wireless terminal device that are communicating at a predetermined frequency bandwidth and center frequency. In a wireless terminal device of a wireless communication system in which communication is continued after changing the mode to the wideband mode, the first mode change information including the mode change timing from the wireless base station device, the frequency bandwidth of the wideband mode, and the center frequency is included. When the control signal is received in the narrowband mode, a means for detecting the interference level at the frequency bandwidth and the center frequency of the wideband mode and transmitting the second control signal including the interference detection result to the radio base station apparatus in the narrowband mode When the interference level is lower than the specified value, the radio base station apparatus instructs the broadband mode to change the mode at the timing of changing the mode. When the control signal is received in the narrowband mode, a reception response is returned, and the processing for changing from the narrowband mode to the wideband mode and the broadband base station apparatus after the change to the wideband mode are performed. And a means for transmitting and receiving a fourth control signal and a reception response in the mode, and thereafter the communication is continued in the broadband mode.

  Whether the interference level at the frequency bandwidth and the center frequency of the wideband mode is less than or equal to a specified value between the wireless base station device and the wireless terminal device that are communicating in the narrowband mode. By checking, it is possible to reliably change the mode from the narrowband mode to the wideband mode without disconnecting communication.

It is a flowchart which shows the mode change procedure in the radio | wireless communications system of this invention. It is a figure which shows the structural example of the radio base station apparatus and radio | wireless terminal apparatus of this invention. It is a figure explaining the subject at the time of the change from narrowband mode to wideband mode.

  FIG. 1 shows a mode change procedure in the wireless communication system of the present invention. FIG. 1A shows a mode change procedure from the narrowband mode to the wideband mode, and FIG. 1B shows a mode change procedure from the wideband mode to the narrowband mode. Here, the notation of data frame transmission / reception is omitted, and only the control signals and reception responses shown below are shown.

  In FIG. 1 (a), it is assumed that the radio base station apparatus and the radio terminal apparatus are communicating in a narrow band mode. When the radio base station apparatus changes the mode from the narrowband mode to the wideband mode, first, the control signal 1 including the mode change information having the mode change timing, the frequency bandwidth of the wideband mode, and the center frequency is transmitted (S1). ). Note that the mode change timing is indicated by, for example, the number N of frames transmitted before the mode change.

  The wireless terminal device that has received the control signal 1 transmits a reception response (S2), and detects the interference level at the frequency bandwidth and the center frequency in the wideband mode (S3). Then, the control signal 2 including the interference detection result is transmitted to the radio base station apparatus (S4). The radio base station apparatus that has received the control signal 2 transmits a reception response (S5). Here, if the interference level exceeds the specified value, the radio base station apparatus and the radio terminal apparatus cancel the mode change procedure.

  On the other hand, if the interference level is less than or equal to the specified value, the radio base station apparatus transmits a control signal 3 instructing mode change at the timing of mode change (after N frames) (S6). The wireless terminal device that has received the control signal 3 transmits a reception response (S7). Thereafter, both the radio base station apparatus and the radio terminal apparatus change the mode from the narrowband mode to the wideband mode (S8).

  The radio base station apparatus that has been changed to the broadband mode transmits a control signal 4 for confirming the mode change in the broadband mode (S9), and the radio terminal apparatus that has received the control signal 4 transmits a reception response in the broadband mode (S10). . Thereafter, the wireless base station device and the wireless terminal device continue communication in the broadband mode.

  In FIG. 1B, when the radio base station apparatus and the radio terminal apparatus are communicating in the wideband mode, when changing the mode from the wideband mode to the narrowband mode, step S3 in FIG. The processes of .about.S5 are omitted, and the other processes are the same as those in FIG. However, the mode change information is indicated by the mode change timing, the frequency bandwidth of the narrowband mode, and the center frequency.

FIG. 2 shows a configuration example of a radio base station apparatus and a radio terminal apparatus according to the present invention.
In FIG. 2, the radio base station apparatus includes a transmission / reception unit 21, a mode change control unit 22, and a mode change determination unit 23. The mode change control unit 22 performs transmission / reception control of the control signal 1, the control signal 3, the control signal 4, and each reception response related to the mode change shown in FIG. The mode change process is performed on the transmission / reception unit 21 by receiving the reception response. Whether the mode change determination unit 23 receives the control signal 2 including the interference detection result notified from the wireless terminal device, and performs the mode change from the narrowband mode to the wideband mode according to the interference level in the wireless terminal device. Determine whether or not.

  The wireless terminal device includes a transmission / reception unit 24, a mode change control unit 25, and an interference detection processing unit 26. The mode change control unit 25 performs transmission / reception control of the control signal 1, the control signal 3, the control signal 4, and each reception response related to the mode change transmitted from the radio base station apparatus, and receives and transmits the control signal 3. A mode change process is performed on The interference detection processing unit 26 detects an interference level according to mode change information (frequency bandwidth and center frequency in the wideband mode) included in the control signal 1 transmitted from the radio base station apparatus, and performs control including the interference detection result. Transmission / reception processing of signal 2 and reception response is performed.

DESCRIPTION OF SYMBOLS 21 Transmission / reception part 22 Mode change control part 23 Mode change determination part 24 Transmission / reception part 25 Mode change control part 26 Interference detection process part

Claims (8)

The mode is changed from the narrowband mode of the predetermined frequency bandwidth to the wideband mode of the relatively wide frequency bandwidth between the wireless base station device and the wireless terminal device communicating with the predetermined frequency bandwidth and center frequency. In a wireless communication system that continues communication,
The radio base station apparatus notifies the radio terminal apparatus of a mode change to the wideband mode, and the radio terminal apparatus detects an interference level at a frequency bandwidth and a center frequency of the wideband mode based on the notification. A radio communication system, wherein the radio base station apparatus and the radio terminal apparatus change the mode to the broadband mode when the radio base station apparatus is notified and the interference level is equal to or less than a specified value. The mode is changed from the narrowband mode of the predetermined frequency bandwidth to the wideband mode of the relatively wide frequency bandwidth between the wireless base station device and the wireless terminal device communicating with the predetermined frequency bandwidth and center frequency. In a wireless communication system that continues communication,
The radio base station apparatus transmits a first control signal including mode change information having the mode change timing and the frequency bandwidth and center frequency of the wideband mode to the radio terminal apparatus in the narrowband mode. With means,
When the wireless terminal device receives the first control signal, the wireless terminal device detects an interference level at a frequency bandwidth and a center frequency in the wideband mode, and outputs a second control signal including an interference detection result in the narrowband mode. Means for transmitting to the radio base station apparatus;
The radio base station apparatus receives the second control signal, and when the interference level is equal to or lower than a predetermined value, a third control signal for instructing the broadband mode to change the mode at the timing of changing the mode, Means for transmitting to the wireless terminal device in the narrowband mode;
When the wireless terminal device receives the third control signal, the wireless terminal device returns a reception response, and includes means for performing processing for changing from the narrowband mode to the wideband mode,
The radio base station device comprises means for performing a process of changing from the narrowband mode to the wideband mode upon receiving a reception response to the third control signal,
The radio base station apparatus and the radio terminal apparatus are configured to transmit and receive a fourth control signal and a reception response in the wideband mode after changing to the wideband mode, and then continue communication in the wideband mode. A wireless communication system. The mode is changed from the narrowband mode of the predetermined frequency bandwidth to the wideband mode of the relatively wide frequency bandwidth between the wireless base station device and the wireless terminal device communicating with the predetermined frequency bandwidth and center frequency. In the wireless communication method for continuing communication,
The radio base station apparatus notifies the radio terminal apparatus of a mode change to the wideband mode, and the radio terminal apparatus detects an interference level in a frequency bandwidth and a center frequency of the wideband mode based on the notification, and A radio communication method comprising: notifying a radio base station device, and changing the mode to the broadband mode when the interference level is equal to or less than a specified value. The mode is changed from the narrowband mode of the predetermined frequency bandwidth to the wideband mode of the relatively wide frequency bandwidth between the wireless base station device and the wireless terminal device communicating with the predetermined frequency bandwidth and center frequency. In the wireless communication method for continuing communication,
The radio base station apparatus transmits a first control signal including mode change information having the mode change timing and the frequency bandwidth and center frequency of the wideband mode to the radio terminal apparatus in the narrowband mode. ,
When the wireless terminal device receives the first control signal, the wireless terminal device detects an interference level at a frequency bandwidth and a center frequency in the wideband mode, and outputs a second control signal including an interference detection result in the narrowband mode. Transmitted to the radio base station device,
The radio base station apparatus receives the second control signal, and when the interference level is equal to or lower than a predetermined value, a third control signal for instructing the broadband mode to change the mode at the timing of changing the mode, Transmitting to the wireless terminal device in the narrowband mode,
When receiving the third control signal, the wireless terminal device returns a reception response and performs a process of changing from the narrowband mode to the wideband mode,
When the radio base station apparatus receives a reception response to the third control signal, the radio base station apparatus performs a process of changing from the narrowband mode to the wideband mode,
The radio base station apparatus and the radio terminal apparatus transmit and receive a fourth control signal and a reception response in the wideband mode after changing to the wideband mode, and then continue communication in the wideband mode. Wireless communication method. The mode is changed from the narrowband mode of the predetermined frequency bandwidth to the wideband mode of the relatively wide frequency bandwidth between the wireless base station device and the wireless terminal device communicating with the predetermined frequency bandwidth and center frequency. In the radio base station apparatus of the radio communication system that continues communication,
When notifying a mode change to the wideband mode to the wireless terminal device, and the interference level at the center frequency and the frequency bandwidth of the wideband mode detected by the wireless terminal device in response to the notification, A radio base station apparatus, characterized in that the mode is changed to the broadband mode. The mode is changed from the narrowband mode of the predetermined frequency bandwidth to the wideband mode of the relatively wide frequency bandwidth between the wireless base station device and the wireless terminal device communicating with the predetermined frequency bandwidth and center frequency. In the radio base station apparatus of the radio communication system that continues communication,
Means for transmitting, to the wireless terminal device in the narrowband mode, a first control signal including mode change information having the mode change timing and the frequency bandwidth and center frequency of the wideband mode;
When the frequency bandwidth of the broadband mode detected by the wireless terminal device with respect to the first control signal and the interference level at the center frequency are below a specified value, the mode is changed to the broadband mode at the timing of changing the mode. Means for transmitting a third control signal instructing to the wireless terminal device in the narrowband mode;
Means for performing a process of changing from the narrowband mode to the wideband mode upon receipt of a reception response transmitted from the wireless terminal device in response to the third control signal;
And a means for transmitting and receiving a fourth control signal and a reception response in the wideband mode with the wireless terminal device after changing to the wideband mode, and thereafter continuing communication in the wideband mode. A radio base station apparatus characterized by the above. The mode is changed from the narrowband mode of the predetermined frequency bandwidth to the wideband mode of the relatively wide frequency bandwidth between the wireless base station device and the wireless terminal device communicating with the predetermined frequency bandwidth and center frequency. In the wireless terminal device of the wireless communication system that continues communication,
When notified of the change to the broadband mode from the radio base station apparatus, the interference level in the frequency bandwidth and center frequency of the broadband mode is detected and notified to the radio base station apparatus, and the interference level is defined The wireless terminal device is configured to change the mode to the broadband mode when the value is less than or equal to the value. The mode is changed from the narrowband mode of the predetermined frequency bandwidth to the wideband mode of the relatively wide frequency bandwidth between the wireless base station device and the wireless terminal device communicating with the predetermined frequency bandwidth and center frequency. In the wireless terminal device of the wireless communication system that continues communication,
When receiving in the narrowband mode a first control signal including mode change information having the mode change timing and the frequency bandwidth and center frequency of the wideband mode from the radio base station apparatus, the frequency band of the wideband mode Means for detecting an interference level at a width and a center frequency, and transmitting a second control signal including an interference detection result to the radio base station apparatus in the narrowband mode;
When the third control signal instructing mode change to the wideband mode is received in the narrowband mode at the timing of changing the mode from the radio base station apparatus when the interference level is less than a specified value, a reception response is returned. And means for performing processing for changing from the narrowband mode to the wideband mode;
And a means for transmitting and receiving a fourth control signal and a reception response to and from the radio base station apparatus in the wideband mode after changing to the wideband mode, and thereafter continuing communication in the wideband mode. A wireless terminal device.

Images