JP2010199922A - Radio repeater and radio repeating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio repeater capable of improving throughput of each radio system while avoiding interference among a plurality of radio systems by preventing occurrence of interference in simultaneous transmission and simultaneous reception for the plurality of radio systems, and considering difference of communication capacity corresponding to a transmission rate of each radio system, and a radio repeating method. <P>SOLUTION: When downlink communication capacity of a first radio system based on a transmission rate of each radio system is larger than that of a second radio system, a downlink period of the first radio system and that of the second radio system are calculated, and an uplink period of the second radio system corresponding to a downlink period of the first radio system is set so that downlink communication capacity values of the respective radio systems are set equal to each other, and transmission on one side of the respective radio systems and reception on the other side thereof are prevented from occurring at the same time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless relay device and a wireless relay method for relaying communication between wireless systems that use frequency bands close to each other. In particular, the present invention relates to a radio relay apparatus and a radio relay method that perform relay processing between radio systems while reducing interference in a situation where leakage power due to proximity of an antenna corresponding to each radio system causes interference.

  Wireless system using access control procedure by autonomous distributed control such as wireless LAN in 2.4GHz band channel called ISM (Industry-Science-Medical) band where various devices such as medical devices and home appliances can be used without wireless license Is popular. This wireless system based on autonomous distributed control is characterized by low power and a narrow communication area, and an access control method (for example, CSMA / CA) based on the premise that interference occurs between wireless systems using the ISM band is adopted. Yes.

  On the other hand, in the proximity frequency of this ISM band, there is a centralized radio system that performs access control by TDD (Time Division Duplexing) or FDD (Frequency Division Duplexing), such as WiMAX (Worldwide Interoperability for Microwave Access). Many of the wireless systems based on this centralized control require a license from a communication carrier, and it is not assumed that the wireless systems interfere with each other. It also features high power and wide area communication areas.

  In addition to the wireless LAN, the wireless system based on autonomous distributed control includes ZigBee, and the wireless system based on centralized control includes next-generation PHS (XG-PHS) in addition to WiMAX.

  In recent years, it is expected that these multiple wireless systems are integrated and complemented with each other, and a wireless terminal having a wireless interface corresponding to the multiple wireless systems appears in one housing. is doing. For example, a mobile terminal called a smartphone equipped with a wireless LAN and a third-generation mobile phone wireless interface, and a wireless relay device having a media conversion function for relaying between the wireless LAN and the third-generation mobile phone have been commercialized. By using this wireless relay device, the wireless LAN terminal can be connected to a wireless system in a wide-area communication area such as a third generation mobile phone, easily expanding the places where the wireless LAN can be used, and improving user convenience Can be improved.

FIG. 7 shows a configuration example of a wireless system including a wireless relay device.
In the figure, the wireless relay device 50 is wirelessly connected to the wireless LAN terminal 60 using the wireless LAN function, wirelessly connected to the WiMAX base station 70 using the WiMAX function, and connected to the network 80 via the WiMAX base station 70. To do. At this time, if the wireless LAN terminal 60 is within the service area of the wireless relay device 50, it can be connected to the network 80 via the wireless relay device 50.

  Such a wireless relay device 50 is connected to an antenna 54 connected to a WiMAX interface 51 that functions as a WiMAX terminal and a wireless LAN interface 52 that functions as a wireless LAN base station, for example, as shown in FIG. When the antenna 55 is close in the same casing, interference due to leakage power between the antennas occurs. Here, FIG. 8 (2) shows the relationship between the transmission power radiated outside the use frequency band of the wireless LAN and the reception power of WiMAX. Since the transmission power radiated outside the frequency band of use of the wireless LAN has a small propagation loss, it interferes with a WiMAX reception signal having a large propagation loss and greatly deteriorates the reception signal characteristics. The same applies to a WiMAX transmission signal and a wireless LAN reception signal.

  That is, in the wireless relay device, when one wireless system (for example, wireless LAN) is transmitting and the other wireless system (WiMAX) performs reception, interference occurs on the receiving side due to leakage power on the transmitting side. .

  As a method for solving this problem, in Non-Patent Document 1, interference from the transmission side to the reception side is performed by scheduling transmission / reception timing so that one radio system and the other radio system perform simultaneous transmission and simultaneous reception. A method to avoid this is proposed.

  FIG. 9 shows a configuration example of a conventional wireless relay device 50 for avoiding interference. Here, a wireless relay apparatus that relays between the WiMAX network and the wireless LAN in the network configuration shown in FIG. 7 will be described as an example. However, the transmission / reception timing synchronization control is not limited to both WiMAX and wireless LAN. It is applied to relay between wireless systems that can

  In the figure, the wireless relay device 50 includes a WiMAX interface 51 that functions as a WiMAX terminal, and a wireless LAN interface 52 that functions as a wireless LAN base station. Here, the transmission direction from the WiMAX base station 70 to the WiMAX interface (WiMAX terminal) 51 is DL (downlink), the reverse transmission direction is UL (uplink), and the wireless LAN interface (wireless LAN base station) 52 is wireless. The transmission direction to the LAN terminal 60 is DL, and the reverse transmission direction is UL. Furthermore, a scheduler 53 is provided between the WiMAX interface 51 and the wireless LAN interface 52 to determine the DL period and the UL period in the wireless LAN corresponding to the transmission / reception timing of the DL period and the UL period of the WiMAX frame.

FIG. 10 shows an operation example of the conventional wireless relay device 50.
In the figure, the radio frame structure in the WiMAX network is composed of a DL period and a UL period, and the DL period is composed of a header portion such as a preamble signal P, FCH, DL-MAP, UL-MAP, and DL data (DL burst). . A wireless LAN UL period is set for the WiMAX DL period, and a wireless LAN DL period is set for the WiMAX UL period.

  The WiMAX interface 51 of the radio relay apparatus receives the DL subframe in the DL period of the radio frame # 1 transmitted from the WiMAX base station 70, and notifies the scheduler 53 of the WiMAX synchronization time information and the WiMAX DL / UL period. . The scheduler 53 notifies the wireless LAN interface 52 of the time reference, and further notifies the wireless LAN UL / DL period corresponding to the WiMAX DL / UL period. The wireless LAN interface 52 notifies the wireless LAN terminal 60 of the wireless LAN DL period and the UL period using the PSMP frame in the wireless LAN DL period synchronized with the WiMAX UL period, and also transmits the DL data of the WiMAX frame as data. Relay transmission is performed as D1 and D2. Here, a PSMP frame and a plurality of data D1, D2 are continuously transmitted at SIFS / RIFS intervals.

  The wireless LAN terminal 60 receives the data D1 and D2 during the DL period of the wireless LAN notified by the PSMP frame, and continuously transmits the data D3 and D4 to the wireless LAN interface 52 and receives the data during the DL period during the UL period. Block ACKs for the data D1 and D2 are transmitted in a batch.

  On the other hand, the WiMAX interface 51 receives the DL period of the radio frame # 2 in the UL period of the wireless LAN. Here, similarly, it is assumed that the time synchronization process, the wireless LAN UL period and the DL period corresponding to the WiMAX DL period and the UL period are set, and the wireless LAN interface 52 notifies the wireless LAN terminal 60 with a PSMP frame. However, this process does not necessarily have to be performed for each frame.

  In the wireless LAN DL period synchronized with the WiMAX UL period, the wireless LAN interface 52 relays the DL data of the WiMAX frame # 2 as data D5 and D6 to the wireless LAN terminal 60 together with the PSMP frame, and further in the UL period. Block ACKs for the received data D3 and D4 are transmitted collectively. Also, the WiMAX interface 51 relays and transmits data D3 and D4 received during the UL period of the wireless LAN to the WiMAX base station as UL data during the UL period of the WiMAX frame # 2.

  As described above, in the wireless relay device, the DL period of the WiMAX interface 51 and the UL period of the wireless LAN interface 52 are synchronized, and interference between received signals does not occur. Moreover, since the UL period of the WiMAX interface 51 and the DL period of the wireless LAN interface 52 are synchronized and both are signal transmissions, no interference occurs. In other words, when transmission and reception are alternately repeated on the WiMAX network side of the wireless relay device, transmission and reception are alternately repeated at the same timing on the wireless LAN side, and both prevent a decrease in throughput while avoiding interference. can do.

Akira Kishida et al., "Examination of interference avoidance technology in multiple wireless systems", 2008 IEICE Communication Society Conference, B-5-123, September 2008 IEEE P802.11n / D3.02, Draft STANDARD for Information Technology Telecommunications and information exchange between systems Local and metropolitan area networks Specific requirements, 9.15 PSMP Operation, December 2007

  By the way, in the interference avoidance technique described in Non-Patent Document 1, the WiMAX DL period and the UL period are fixed in advance, and the DL period and the UL period in the wireless LAN are synchronized with the transmission / reception timing of the DL period and the UL period of the WiMAX frame. ing.

  At this time, if the WiMAX transmission rate is higher than the wireless LAN transmission rate and the WiMAX DL communication capacity obtained by multiplying each DL period is larger than the wireless LAN DL communication capacity, the WiMAX DL data is wireless. There is a problem that the data stays in the relay device and the DL throughput is substantially reduced. In addition, if such a decrease in DL throughput continues, a buffer overflow in the wireless relay device may occur, and the service may be stopped.

  The present invention prevents interference between a plurality of radio systems from being simultaneously transmitted and received, and considers a difference in communication capacity corresponding to a transmission rate of each radio system, and thus causes interference between a plurality of radio systems. It is an object of the present invention to provide a wireless relay device and a wireless relay method that can improve the throughput of each wireless system while avoiding the above-described problem.

  According to a first aspect of the present invention, there is provided a wireless relay device that relays transfer data between a first wireless system and a second wireless system that use different wireless channels that receive interference due to leakage power. The first interface unit corresponding to the terminal, the second interface unit corresponding to the base station of the second wireless system, and the transmission / reception timing of the second wireless system in synchronization with the transmission / reception timing of the first wireless system. A scheduler configured to obtain a transmission rate and an uplink period and a downlink period of the first wireless system via the first interface unit, and the second wireless unit via the second interface unit. Obtaining the transmission rate of the system and downlink communication capacity of the first wireless system based on the transmission rate of each wireless system Is larger than the downlink communication capacity of the second wireless system, the downlink communication capacity of each wireless system is equal, and the transmission and reception of the other of the wireless systems do not occur simultaneously. A configuration in which a downlink period of the first radio system and a downlink period of the second radio system are calculated, and an uplink period of the second radio system corresponding to the downlink period of the first radio system is set. The first interface unit is configured to notify the base station of the first radio system of the downlink period of the first radio system, and the second interface unit includes the downlink period of the second radio system and The configuration is such that the uplink period is notified to the terminal of the second radio system and the transmission / reception timing of the second radio system is controlled. That.

  In the wireless relay device of the first invention, the scheduler is configured to provide a lower limit value in the downlink period of the first wireless system.

  In the wireless relay device of the first invention, the header portion of the wireless frame of the first wireless system includes transmission / reception timing information, and the first interface portion is based on the transmission / reception timing information of the header portion of the wireless frame, In this configuration, the uplink period and the downlink period of the first wireless network are acquired and notified to the scheduler.

  In the wireless relay device according to the first aspect of the invention, the preamble part of the radio frame of the first radio system includes synchronization time information, and the first interface unit acquires the synchronization time information from the preamble part of the radio frame. The scheduler is configured to notify the scheduler, and the scheduler is configured to determine a time reference in the second wireless system based on the synchronization time information.

  In the wireless relay device of the first invention, the first wireless system is a WiMAX system, the second wireless system is a wireless LAN system, and the second interface unit is wireless LAN power saving (PSMP). This is a configuration for controlling a downlink period and an uplink period of a wireless LAN by using a procedure.

  According to a second aspect of the present invention, there is provided a wireless relay method for relaying transfer data between a first wireless system and a second wireless system that use different wireless channels that receive interference due to leakage power. The first interface unit corresponding to the terminal, the second interface unit corresponding to the base station of the second wireless system, and the transmission / reception timing of the second wireless system in synchronization with the transmission / reception timing of the first wireless system. A scheduler configured to obtain a transmission rate and an uplink period and a downlink period of the first wireless system via the first interface unit, and the second wireless unit via the second interface unit. Obtaining the transmission rate of the system and downlink communication capacity of the first wireless system based on the transmission rate of each wireless system Is larger than the downlink communication capacity of the second wireless system, the downlink communication capacity of each wireless system is equal, and the transmission and reception of the other of the wireless systems do not occur simultaneously. Calculating a downlink period of the first radio system and a downlink period of the second radio system, further setting an uplink period of the second radio system corresponding to the downlink period of the first radio system, The interface unit notifies the downlink period of the first radio system to the base station of the first radio system, and the second interface unit sets the downlink period and the uplink period of the second radio system to the second period. To the terminal of the wireless system, and controls the transmission / reception timing of the second wireless system.

  In the wireless relay method of the second invention, the scheduler sets a lower limit value in the downlink period of the first wireless system.

  Further, in the wireless relay method of the second invention, information on transmission / reception timing is included in the header portion of the wireless frame of the first wireless system, and the first interface portion is based on information on transmission / reception timing in the header portion of the wireless frame, The uplink period and downlink period of the first wireless network are acquired and notified to the scheduler.

  In the wireless relay method according to the second aspect of the invention, the preamble part of the radio frame of the first radio system includes synchronization time information, and the first interface unit acquires the synchronization time information from the preamble part of the radio frame. The scheduler is notified, and the scheduler determines a time reference in the second wireless system based on the synchronization time information.

  In the wireless relay method of the second invention, the first wireless system is a WiMAX system, the second wireless system is a wireless LAN system, and the second interface unit is a wireless LAN power saving (PSMP). Using the procedure, the downlink period and the uplink period of the wireless LAN are controlled.

  In the present invention, the first relay system side and the second wireless system side of the wireless relay device are controlled so that one transmission and the other reception do not occur at the same time, thereby reducing the throughput while avoiding mutual interference. Can be suppressed. Further, when the downlink communication capacity of the first wireless system is larger than the downlink communication capacity of the second wireless system, the respective downlink periods are adjusted so that the downlink communication capacities are equal. As a result, the downlink communication capacities of both wireless systems become equal, transfer data can be prevented from staying in the wireless relay device, and the throughput of the entire system in the downlink direction can be improved.

  Moreover, the present invention can guarantee the minimum value of the uplink communication capacity by setting the lower limit value of the uplink period of the second radio system corresponding to the downlink period of the first radio system.

It is a figure which shows the structural example of Example 1 of the radio relay apparatus of this invention. FIG. 4 is a diagram illustrating a control sequence of the wireless relay device 10 according to the first embodiment. 3 is a flowchart illustrating a processing procedure of a scheduler 13 of the wireless relay device 10 according to the first embodiment. It is a time chart explaining the outline | summary of a PSMP sequence. 3 is a time chart illustrating an operation example of the wireless relay device 10 according to the first embodiment. 10 is a flowchart illustrating a processing procedure of a scheduler 13 of the wireless relay device 10 according to the second embodiment. It is a figure which shows the example of a radio | wireless system structure containing a radio relay apparatus. It is a figure explaining the interference factor of a radio relay apparatus. It is a figure which shows the structural example of the conventional radio relay apparatus 50 for interference avoidance. 10 is a time chart showing an operation example of a conventional wireless relay device 50. It is a figure which shows the throughput characteristic (wireless LAN transmission rate: 24 Mbps) of a downlink. It is a figure which shows the throughput characteristic (wireless LAN transmission rate: 54 Mbps) of a downlink. It is a figure which shows the throughput characteristic (wireless LAN transmission rate: 24 Mbps) of an uplink. It is a figure which shows the throughput characteristic (wireless LAN transmission rate: 54 Mbps) of an uplink.

  FIG. 1 shows a configuration example of Embodiment 1 of the wireless relay device of the present invention. In the first embodiment, a wireless relay device that relays between a WiMAX network and a wireless LAN in the network configuration shown in FIG. 7 will be described as an example. However, the present invention is not limited to WiMAX and wireless LAN, and the present invention is applied to both wireless systems. It can be applied to relay between wireless systems capable of synchronous control of transmission / reception timing.

  In the figure, a wireless relay device 10 includes a WiMAX interface 11 that functions as a WiMAX terminal, and a wireless LAN interface 12 that functions as a wireless LAN base station. Here, the transmission direction from the WiMAX base station 70 to the WiMAX interface (WiMAX terminal) 11 is DL (downlink), the reverse transmission direction is UL (uplink), and the wireless LAN interface (wireless LAN base station) 12 is wireless. The transmission direction to the LAN terminal 60 is DL, and the reverse transmission direction is UL. Further, the scheduler 13 arranged between the WiMAX interface 11 and the wireless LAN interface 12 inputs the WiMAX DL / UL period and the transmission rate from the WiMAX interface 11, and inputs the wireless LAN transmission level from the wireless LAN interface 12. Then, the UL / DL period of the wireless LAN corresponding to the WiMAX DL / UL period is set so that the DL communication capacities corresponding to the transmission rates of the WiMAX and the wireless LAN become equal. Details will be described later.

FIG. 2 illustrates a control sequence of the wireless relay device 10 according to the first embodiment. FIG. 3 illustrates a processing procedure of the scheduler 13 of the wireless relay device 10 according to the first embodiment.
In FIG. 2, a WiMAX interface (WiMAX terminal) 11 receives a DL subframe transmitted by the WiMAX base station 70 in the DL period, acquires synchronization time information from the preamble signal at the head thereof, and notifies the scheduler 13 of the synchronization time information. The scheduler 13 determines a time reference in the wireless LAN based on the synchronization time information, and notifies the wireless LAN interface (wireless LAN base station) 12 of the time reference. The wireless LAN interface 12 synchronizes its timer with this time reference, and synchronizes the time between WiMAX and the wireless LAN.

  The WiMAX interface 11 detects the WiMAX DL / UL period and the transmission rate from the FCH, DL-MAP, UL-MAP, and the like at the beginning of the DL subframe, and notifies the scheduler 13 of them. On the other hand, the wireless LAN interface 12 notifies the scheduler 13 of the transmission rate of the wireless LAN.

  As shown in FIG. 3, the scheduler 13 acquires the WiMAX DL / UL period (S1), acquires the WiMAX transmission rate (S2), acquires the wireless LAN transmission rate (S3), and then acquires the WiMAX DL. The communication capacity is compared with the DL communication capacity of the wireless LAN (S4). Here, the WiMAX DL communication capacity is (WiMAX transmission rate) × (WiMAX DL period) × (WiMAX MAC efficiency). The DL communication capacity of the wireless LAN is (wireless LAN transmission rate) × (wireless LAN DL period) × (wireless LAN MAC efficiency).

  The DL communication capacity of the WiMAX and the DL communication capacity of the wireless LAN are compared (S4). If the DL communication capacity of the wireless LAN is large or equal, the wireless LAN UL / DL corresponding to the WiMAX DL / UL period is conventionally used. A DL period is set (S5), and the wireless LAN interface 12 is notified (S8).

  On the other hand, when the WiMAX DL communication capacity is large, the WiMAX DL data allocation impossible period in which the WiMAX DL communication capacity and the wireless LAN DL communication capacity are equal is calculated, and the WiMAX DL valid period and the wireless LAN DL are calculated. A period and a UL period are set (S6). That is, a WiMAX DL effective period that is shortened by a DL data non-assignable period from the WiMAX default DL period is calculated, and a wireless LAN DL period corresponding to the WiMAX default UL period is added to the DL data non-assignable period. The DL period of the LAN is calculated. Also, the wireless LAN UL period corresponding to the WiMAX DL valid period is set.

  Here, the WiMAX DL data unassignable period is a free period of the DL period for reducing the DL communication capacity, and the WiMAX (predetermined DL period-DL data unassignable period) is the DL valid period. , It does not change the default DL period in WiMAX. The DL data unassignable period may be a free period that is not used for communication, or may be used for transmission to another WiMAX terminal.

  The scheduler 13 notifies the WiMAX interface 11 of the WiMAX DL effective period (DL data unassignable period) (S7), and notifies the WiMAX base station from the WiMAX interface 11 during the WiMAX UL period. Further, the scheduler 13 notifies the wireless LAN interface 12 of the wireless LAN UL period corresponding to the WiMAX DL valid period and the wireless LAN DL period corresponding to the WiMAX (UL period + DL data unassignable period) (S8). ).

  The wireless LAN interface 12 transmits the DL / UL period of the wireless LAN to the wireless LAN terminal 60 during the DL period of the wireless LAN. The wireless LAN interface 12 and the wireless LAN terminal 60 perform data transmission / reception processing in accordance with the DL / UL period of the wireless LAN. That is, in the wireless relay device 10, the WiMAX DL valid period and the wireless LAN UL period are synchronized, the WiMAX (UL period + DL data unassignable period) and the wireless LAN DL period are synchronized, and the WiMAX and the wireless LAN are synchronized. It is a mechanism to avoid mutual interference by preventing one transmission and the other reception from occurring at the same time.

  The WiMAX network and the wireless LAN are synchronized in time based on time information obtained from the preamble signal of the WiMAX DL period, but due to processing delay of the wireless LAN, for example, the wireless LAN DL period is delayed and WiMAX is delayed. It is conceivable that transmission of the wireless LAN DL period and reception of the WiMAX DL period overlap and cause interference. In this case, the scheduler 13 determines the wireless LAN delay time by comparing the UL period set for the wireless LAN and the reception timing of the UL data, and shortens the end of each of the DL period and the UL period by the delay time. Alternatively, a no-signal section may be set to avoid interference between the wireless LAN and WiMAX.

  Incidentally, the control of the DL period and the UL period in the wireless LAN can be realized by a PSMP (Power Save Multi-Poll) function which is a new power saving procedure defined by IEEE802.11n (see Non-Patent Document 2).

FIG. 4 shows an outline of the PSMP sequence.
In the figure, a wireless LAN base station 31 transmits a PSMP frame to wireless LAN terminals 32 and 33 to be connected. In the PSMP frame, a reception start time t1 and a transmission start time t3 assigned to the wireless LAN terminal 32, and a reception start time t2 and a transmission start time t4 assigned to the wireless LAN terminal 33 are described. The wireless LAN terminal 32 receives DL data from the reception start time t1 notified by the PSMP frame, transmits UL data from the transmission start time t3, and enters the power save mode at other times. The wireless LAN terminal 33 receives DL data from the reception start time t2 notified by the PSMP frame, transmits UL data from the transmission start time t4, and enters the power save mode at other times. Thus, the wireless LAN terminal performs transmission / reception at the timing notified by the PSMP frame, and stops data transmission / reception during other periods.

  In this embodiment, the time t1 to t3 corresponds to the DL period of the wireless LAN, and DL data is transmitted, and the UL subframe is transmitted on the WiMAX side. Also, the time t3 to t5 corresponds to the UL period of the wireless LAN and UL data is received, and the DL subframe is received on the WiMAX side.

FIG. 5 illustrates an operation example of the wireless relay device 10 according to the first embodiment.
In the figure, the radio frame structure in the WiMAX network is composed of a DL period and a UL period, and the DL period is composed of a header portion such as a preamble signal P, FCH, DL-MAP, UL-MAP, and DL data (DL burst). The Normally, the wireless LAN UL period is set for the WiMAX DL period, and the wireless LAN DL period is set for the WiMAX UL period.

  The WiMAX interface 11 of the radio relay apparatus receives the DL subframe in the DL period of the radio frame # 1 transmitted from the WiMAX base station 70, and the scheduler 13 determines the WiMAX synchronization time information, the WiMAX transmission rate, and the DL / UL period. Notify The scheduler 13 notifies the wireless LAN interface 2 of the time reference. On the other hand, the wireless LAN interface 12 notifies the scheduler 13 of the transmission rate of the wireless LAN.

  As shown in FIG. 3, when the WiMAX DL communication capacity is larger than the wireless LAN DL communication capacity, the scheduler 13 assigns the WiMAX DL data allocation so that the WiMAX DL communication capacity is equal to the wireless LAN DL communication capacity. The impossible period is calculated, the WiMAX DL valid period (DL data allocation impossible period), the wireless LAN DL period, and the UL period are set, and notified to the WiMAX interface 11 and the wireless LAN interface 12, respectively.

  The WiMAX interface 11 notifies the WiMAX base station 70 of the WiMAX DL effective period (DL data unassignable period) in the UL period, and the WiMAX base station 70 sets the DL data unassignable period in the DL period of the next radio frame # 2. Set and reduce DL communication capacity.

  The wireless LAN interface 12 notifies the wireless LAN terminal 60 of the UL / DL period of the wireless LAN using the PSMP frame in the DL period, and relays and transmits the DL data of the WiMAX frame as data D1 and D2. Here, a PSMP frame and a plurality of data D1, D2 are continuously transmitted at SIFS / RIFS intervals.

  The wireless LAN terminal 60 receives the data D1 and D2 in the DL period of the wireless LAN notified by the PSMP frame, and continuously transmits the data D3 and D4 to the wireless LAN interface 12 and receives the data in the DL period in the UL period. Block ACKs for the data D1 and D2 are transmitted in a batch.

  On the other hand, the WiMAX interface 11 receives the DL subframe of the radio frame # 2 in the DL effective period obtained by shortening the DL data allocation impossible period from the predetermined DL period. Here, similarly, the time synchronization processing, the WiMAX DL / UL transmission rate, the wireless LAN transmission rate, and the wireless LAN UL / DL period corresponding to the WiMAX DL / UL period are set. Although it is assumed that the wireless LAN terminal 60 is notified by a PSMP frame, this process does not necessarily have to be performed for each frame.

  The wireless LAN interface 12 relays and transmits the DL data of the WiMAX frame # 2 as data D5 and D6 together with the PSMP frame to the wireless LAN terminal 60 in the DL period in which the DL data allocation impossible period is added before the WiMAX UL period. In addition, block ACKs for the data D3 and D4 received in the UL period are collectively transmitted. Also, the WiMAX interface 11 relays and transmits data D3 and D4 received during the UL period of the wireless LAN to the WiMAX base station as UL data during the UL period of the WiMAX frame # 2.

  In this way, in the wireless relay device, the WiMAX DL effective period and the wireless LAN UL period are synchronized, and interference between received signals does not occur. Also, the WiMAX UL period + DL data allocation impossible period and the wireless LAN DL period are synchronized, and interference due to signal transmission does not occur. That is, control is performed so that one transmission and the other reception do not occur simultaneously on the WiMAX network side and the wireless LAN side of the wireless relay device, and a reduction in throughput can be suppressed while avoiding mutual interference. Further, when the WiMAX DL communication capacity is larger than the DL communication capacity of the wireless LAN, the WiMAX DL period is shortened so that the DL communication capacities are equal, and the shortened period is added to the DL period of the wireless LAN. Thereby, the DL communication capacity of WiMAX and the DL communication capacity of the wireless LAN become equal, and the throughput in the DL direction can be improved.

  In the processing of the scheduler 13 according to the first embodiment, if the WiMAX transmission rate is much larger than the wireless LAN transmission rate, and the WiMAX DL communication capacity is made equal to the wireless LAN communication capacity, the WiMAX DL data Unallocated period becomes very large. As a result, the WiMAX DL effective period (= predetermined DL period−DL data unassignable period) becomes very small. For this reason, the UL period of the wireless LAN also becomes very small according to the WiMAX DL effective period, and the UL throughput of the entire system is significantly reduced.

  Therefore, in the second embodiment, in preparation for a case where the WiMAX transmission rate is much larger than the wireless LAN transmission rate, the scheduler 13 performs scheduling by setting a lower limit value (required minimum UL period) in the wireless LAN UL period. .

FIG. 6 illustrates a processing procedure of the scheduler 13 of the wireless relay device 10 according to the second embodiment.
In the figure, steps S1 to S8 are the same as those in the first embodiment shown in FIG. In the second embodiment, when the WiMAX DL effective period obtained in step S6 falls below the lower limit value, processing S6a and S6b for setting the WiMAX DL effective period to the lower limit value are added. That is, the wireless LAN UL period corresponds to the WiMAX DL effective period, as shown in FIG. 2 and FIG. 5, so that the WiMAX DL effective period is set not to be lower than the lower limit in steps S6a and S6b. Thus, a lower limit value (necessary minimum UL period) of the UL period of the wireless LAN is secured.

  FIG. 11 shows downlink throughput characteristics (wireless LAN transmission rate: 24 Mbps). FIG. 12 shows downlink throughput characteristics (wireless LAN transmission rate: 54 Mbps). FIG. 13 shows uplink throughput characteristics (wireless LAN transmission rate: 24 Mbps). FIG. 14 shows uplink throughput characteristics (wireless LAN transmission rate: 54 Mbps). In both cases, it is understood that by performing scheduling according to the WiMAX and wireless LAN DL communication capacity of the present invention, the throughput (system throughput) of the wireless LAN can be greatly improved as compared with the conventional configuration in which the scheduling is not performed. .

10, 50 Wireless relay device 11, 51 WiMAX interface (WiMAX terminal)
12, 52 Wireless LAN interface (wireless LAN base station)
13, 53 Scheduler 54, 55 Antenna 60 Wireless LAN terminal 70 WiMAX base station 80 Network

Claims (10)

In a wireless relay device that relays transfer data between a first wireless system and a second wireless system that use different wireless channels that receive interference due to leakage power,
A first interface unit corresponding to a terminal of the first wireless system;
A second interface unit corresponding to a base station of the second wireless system;
A scheduler for setting transmission / reception timing of the second wireless system in synchronization with transmission / reception timing of the first wireless system;
The scheduler acquires a transmission rate, an uplink period, and a downlink period of the first wireless system via the first interface unit, and receives the transmission rate of the second wireless system via the second interface unit. When the downlink communication capacity of the first wireless system based on the transmission rate of each wireless system is greater than the downlink communication capacity of the second wireless system based on the transmission rate of each wireless system, the downlink of each wireless system The downlink period of the first radio system and the downlink period of the second radio system are calculated so that the communication capacities are equal and the transmission and reception of the other radio system do not occur simultaneously. In addition, the second wireless system corresponding to the downlink period of the first wireless system It is configured to set the Uplink period,
The first interface unit is configured to notify a base station of the first radio system of a downlink period of the first radio system;
The second interface unit is configured to notify a terminal of the second radio system of a downlink period and an uplink period of the second radio system and control transmission / reception timing of the second radio system. A wireless relay device characterized by that. The wireless relay device according to claim 1,
The scheduler is configured to provide a lower limit value in a downlink period of the first radio system. The wireless relay device according to claim 1,
Including the transmission / reception timing information in the header portion of the radio frame of the first radio system;
The first interface unit is configured to acquire an uplink period and a downlink period of the first radio network from the transmission / reception timing information of the header part of the radio frame and notify the scheduler. A wireless relay device. The wireless relay device according to claim 1,
Including synchronization time information in a preamble portion of a radio frame of the first radio system;
The first interface unit is configured to acquire the synchronization time information from a preamble unit of the radio frame and notify the scheduler.
The wireless relay device, wherein the scheduler is configured to determine a time reference in the second wireless system based on the synchronization time information. The wireless relay device according to claim 1,
The first wireless system is a WiMAX system;
The second wireless system is a wireless LAN system;
The wireless relay device, wherein the second interface unit is configured to control a downlink period and an uplink period of the wireless LAN by using the wireless LAN power saving (PSMP) procedure. In a wireless relay method for relaying transfer data between a first wireless system and a second wireless system that use different wireless channels that receive interference due to leakage power,
A first interface unit corresponding to a terminal of the first wireless system;
A second interface unit corresponding to a base station of the second wireless system;
A scheduler for setting transmission / reception timing of the second wireless system in synchronization with transmission / reception timing of the first wireless system;
The scheduler acquires a transmission rate, an uplink period, and a downlink period of the first wireless system via the first interface unit, and receives the transmission rate of the second wireless system via the second interface unit. When the downlink communication capacity of the first wireless system based on the transmission rate of each wireless system is greater than the downlink communication capacity of the second wireless system based on the transmission rate of each wireless system, the downlink of each wireless system The downlink period of the first radio system and the downlink period of the second radio system are calculated so that the communication capacities are equal and the transmission and reception of the other radio system do not occur simultaneously. In addition, the second wireless system corresponding to the downlink period of the first wireless system Set the Uplink period,
The first interface unit notifies a base station of the first radio system of a downlink period of the first radio system;
The second interface unit notifies a terminal of the second radio system of a downlink period and an uplink period of the second radio system, and controls transmission / reception timing of the second radio system. A wireless relay method. In the wireless relay method according to claim 6,
The wireless relay method according to claim 1, wherein the scheduler sets a lower limit value in a downlink period of the first wireless system. In the wireless relay method according to claim 6,
Including the transmission / reception timing information in the header portion of the radio frame of the first radio system;
The first interface unit acquires an uplink period and a downlink period of the first radio network from the transmission / reception timing information in the header part of the radio frame, and notifies the scheduler of the uplink period and the downlink period. Wireless relay method. In the wireless relay method according to claim 6,
Including synchronization time information in a preamble portion of a radio frame of the first radio system;
The first interface unit acquires the synchronization time information from the preamble unit of the radio frame and notifies the scheduler,
The scheduler determines a time reference in the second radio system based on the synchronization time information. In the wireless relay method according to claim 6,
The first wireless system is a WiMAX system;
The second wireless system is a wireless LAN system;
The wireless interface method, wherein the second interface unit controls a downlink period and an uplink period of the wireless LAN by using a power saving (PSMP) procedure of the wireless LAN.

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