KR101101952B1 - Method and device for communication between WLAN module and RFID module using common RF module - Google Patents

Abstract

The disclosed technology relates to a method and apparatus for communicating with a wireless communication technology including a wireless LAN (WLAN) and a worldwide interoperability for microwave access (WiMAX) using a common radio frequency (RF) module. Among the embodiments, a method in which a device supporting a wireless communication technology including a wireless LAN (WLAN) and a worldwide interoperability for microwave access (WiMAX) communicates using a common radio frequency (RF) module may include an arbitration module. Receiving an RF occupancy request message or an RF de-occupancy request message sent from at least one of the WLAN module and the WiMAX module; Determining, by the arbitration module, a module to use the RF module of the WLAN module and the WiMAX module based on the received message; And transmitting, by the RF module, a packet provided from the determined module, or providing the received packet to the determined module.

Description

METHOD AND APPARATUS TO COMMUNICATE FOR WLAN MODULE AND WiMAX MODULE USING COMMON RF MODULE}

The disclosed technology relates to a method in which a device conforming to a plurality of wireless communication standards communicates using a common radio frequency (RF) module. More specifically, but not limited to, a wireless LAN (WLAN) and a worldwide interoperability for microwave access (WiMAX) A device supporting a wireless communication technology including a communication method using a common RF (Radio Frequency) module.

The wireless communication terminal can be designed to conform to a plurality of wireless communication standards, and it is possible to connect to a plurality of wireless networks using a plurality of wireless communication standards. For example, it is possible for one wireless communication terminal to communicate with a different counterpart terminal by connecting to a WiFi network and a WiMAX network. WiFi is a trade name of the Wi-Fi Alliance, which refers to a set of technologies related to IEEE 802.11-based Wireless Local Area Network (WLAN) connectivity. WiFi is widely used in short-range communications because of its high transmission speed and low cost. WiMAX is a communication technology based on the IEEE 802.16 standard for Wireless Metropolitan Area Network (WMAN). WiMAX offers wide coverage and high mobility, which is increasing in recent years. Due to the complementary features of WiFi and WiMAX, communication terminals using both communication standards are increasing.

An object of the present invention is to provide a method and apparatus for communicating between a WLAN module and a WiMAX module using a common RF module.

In order to accomplish the above technical problem, a first aspect of the disclosed technology is that a device supporting a wireless communication technology including a wireless LAN (WLAN) and a worldwide interoperability for microwave access (WiMAX) uses a common radio frequency (RF) module. A method of communicating, comprising: an arbitration module receiving an RF occupation request message or an RF de-occupation request message transmitted from at least one of a WLAN module and a WiMAX module; Determining, by the arbitration module, a module to use the RF module of the WLAN module and the WiMAX module based on the received message; And the RF module transmitting a packet provided from the determined module or providing a received packet to the determined module.

A second aspect of the disclosed technology to achieve the above technical problem is a WLAN module that supports a wireless LAN (WLAN) wireless communication technology; A WiMAX module supporting Worldwide Interoperability for Microwave Access (WiMAX) wireless communication technology; An RF module for transmitting a packet provided from the WLAN module or the WiMAX module or storing a received packet to the WLAN module or the WiMAX module; And receive an RF occupation request message or an RF release request message transmitted from at least one of the WLAN module and the WiMAX module, and use the RF module of the WLAN module and the WiMAX module based on the received message. Provides a wireless communication device in which a WLAN module including an arbitration module (Arbitrator) for determining a module and a WiMAX module communicate using a common RF module.

Embodiments of the disclosed technique may have effects that include the following advantages. It should be understood, however, that the scope of the disclosed technology is not to be construed as limited thereby, since the embodiments of the disclosed technology are not meant to include all such embodiments.

According to the disclosed technology, it is possible to efficiently share a common RF module between the WLAN module and the WiMAX module. Thus, the WLAN module and the WiMAX module can reduce size, power consumption, and cost compared to using their own RF modules. In addition, the disclosed technology has the advantage that it can be implemented without particular difficulties without changing the existing WiFi, WiMAX communication specifications.

1 is a diagram schematically illustrating a wireless communication terminal according to an embodiment of the disclosed technology.
2 is a block diagram illustrating a wireless communication terminal according to an embodiment of the disclosed technology.
3 is a view for explaining a busy period (hereinafter referred to as BPR) and an idle period (IPR) in WiFi and WiMAX as an example.
4 illustrates a WiFi frame structure and a WiMAX frame structure according to an embodiment.
5 illustrates a finite state machine (FSM) for access control of an RF module.
6 is a view for explaining an RF module control method in the cooperative mode by way of example.
7 is a table illustrating priorities according to packet types of WiFi and WiMAX.
8 is a diagram for explaining, for example, a method of controlling an RF module in a contention mode.
9 is a flowchart illustrating a method of controlling RF access according to an embodiment of the disclosed technology.
10 is a graph comparing throughput of WiMAX and WiFi according to RF access time in cooperative mode.
11 is a graph illustrating transmission overhead in a contention mode.

The description of the disclosed technique is merely an example for structural or functional explanation and the scope of the disclosed technology should not be construed as being limited by the embodiments described in the text. That is, the embodiments may be variously modified and may have various forms, and thus the scope of the disclosed technology should be understood to include equivalents capable of realizing the technical idea.

On the other hand, the meaning of the terms described in the present application should be understood as follows.

The terms " first ", " second ", and the like are used to distinguish one element from another and should not be limited by these terms. For example, the first component may be named a second component, and similarly, the second component may also be named a first component.

When a component is referred to as being "connected" to another component, it should be understood that there may be other components in between, although it may be directly connected to the other component. On the other hand, when an element is referred to as being "directly connected" to another element, it should be understood that there are no other elements in between. On the other hand, other expressions describing the relationship between the components, such as "between" and "immediately between" or "neighboring to" and "directly neighboring to", should be interpreted as well.

Singular expressions should be understood to include plural expressions unless the context clearly indicates otherwise, and terms such as "include" or "have" refer to features, numbers, steps, operations, components, parts, or parts thereof described. It is to be understood that the combination is intended to be present, but not to exclude in advance the possibility of the presence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof.

Each step may occur differently from the stated order unless the context clearly dictates the specific order. That is, each step may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed technology belongs, unless otherwise defined. Terms such as those defined in the commonly used dictionaries should be construed as consistent with the meanings in the context of the related art, and should not be construed as having ideal or overly formal meanings unless expressly defined in this application. .

Wireless communication terminals can be connected to a plurality of wireless networks by using a plurality of wireless communication standards, and recently, communication terminals using the communication standards of WiFi and WiMAX are increasing. However, existing wireless communication terminals connect to a plurality of communication networks by simply mounting a plurality of unique communication modules inside one terminal. This conventional implementation has a problem of increasing the cost, power consumption and the size of the terminal, and may cause interference between communication modules. Therefore, there is a need for a method of more efficiently designing a wireless communication terminal using a plurality of communication standards.

1 is a diagram schematically illustrating a wireless communication terminal according to an embodiment of the disclosed technology. The wireless communication terminal shown in FIG. 1 communicates with a plurality of communication networks using a common RF module. As in the terminal of FIG. 1, when one RF module is used to perform communication according to a plurality of communication standards (for example, WiFi, WiMAX, etc.), size, power consumption, and cost may be reduced as compared to using respective RF modules. Can be reduced. Hereinafter, a specific method of connecting a plurality of communication networks by controlling a common RF module by a wireless communication terminal will be described with reference to FIGS. 2 to 8. For convenience of description, in the present specification, the WiFi and WiMAX communication standards are described as an example, but similarly applicable to the case of performing communication using other communication standards can be sufficiently understood by those skilled in the art. have.

2 is a block diagram illustrating a wireless communication terminal according to an embodiment of the disclosed technology. The wireless communication terminal 200 of FIG. 2 includes a WiFi communication module and a WiMAX communication module, and can operate in a WiFi / WiMAX dual mode accessible to both WiFi and WiMAX networks. The wireless communication terminal 200 can simultaneously and seamlessly use the WiFi network and the WiMAX network through a time-interleaved access control scheme. That is, the wireless communication terminal 200 enables the WiFi module and the WiMAX module to alternately use the common RF module in the time domain, thereby simultaneously connecting to the WiFi and WiMAX networks. Meanwhile, according to the disclosed technology, since an arbitration layer is newly added between the WiFi and the WiMAX Media Access Control (MAC) layer to control a common RF module, the existing WiFi and WiMAX communication standards do not need to be changed. There is this. For example, the modification of the WiFi and WiMAX MAC layers can be limited to the addition of an arbitration module to make it appear to provide services to users and infrastructure simultaneously.

According to an embodiment, the wireless communication terminal 200 includes a WiFi module 210, a WiMAX module 220, an arbitration module 230, and a common RF module 240. The WiFi module 210 includes a WiFi MAC 212 and a WiFi modem 214, and the WiMAX module 220 includes a WiMAX MAC 222 and a WiMAX modem 224. The common RF module 240 includes an RF multiplexer 242 that receives a packet to transmit by selecting one of the WiFi modem 214 and the WiMAX modem 224. The WiFi module 210 and the WiMAX module 220 may exclusively use the common RF module 240 for communicating with respective communication counterparts such as a WiFi access point (AP) or a WiMAX base station (BS). The arbitration module 230 is a module between the WiFi MAC 212 and the WiMAX MAC 222, and controls each of the two MACs to access the common RF module 240 through a modem. According to an embodiment, the manner in which the arbitration module 230 controls the common RF module 240 includes a cooperative mode scheme and a competitive mode scheme. The cooperative mode control method detects an idle period (hereinafter, referred to as IPR) occurring in one of the WiFi module 210 and the WiMAX module 220 so that the other network module can use the detected IPR. Assignment method. The control mode of the contention mode is a method of allocating a common RF module 240 to one network module regardless of whether a network module of another standard is idle.

3 is a view for explaining a busy period (hereinafter referred to as BPR) and an idle period (IPR) in WiFi and WiMAX as an example. Depending on whether the WiFi MAC 212 or the WiMAX MAC 222 attempts to access the RF module 240 for communication, the time domain may be divided into BPR and IPR. In the cooperative mode, the BPR of either the WiFi module 210 or the WiMAX module 220 is included in the IPR of the other module. The cooperative mode allows the two network modules 210, 220 to alternately occupy a common RF module 240, thereby enabling the wireless communication terminal 200 to use both networks at the same time. On the contrary, when the BPRs of the WiFi module 210 and the WiMAX module 220 overlap each other, the wireless communication terminal 200 operates in a competition mode. In competitive mode, the BPRs of two network modules overlap, so only one of them can communicate. Therefore, in order for the two network modules 210 and 220 to provide a seamless communication service to the user, the IPRs of each module need to be frequently scheduled. In this specification, three methods are proposed in which the arbitration module 230 detects an IPR of one network module and causes the other network module to use it.

First, there are ways to use the power saving modes of WiFi and WiMAX. Since mobile terminals have limited battery life, various power saving techniques are used in wireless technologies including WiFi and WiMAX. WiFi and WiMAX support a power-saving mode. The sleep interval in the power saving mode is an IPR interval, and the arbitration module 230 may use it. For example, during the sleep period of the WiMAX sleep mode, the WiMAX network module 220 temporarily suspends data exchange with the BS. The arbitration module 230 detects the WiMAX power saving mode and schedules the communication traffic so that the WiFi module 210 uses the common RF module 240 during the sleep period of the WiMAX. The opposite is also true. This method has an advantage of providing IPRs having a long interval, but has a disadvantage in that throughput may be lowered due to a delay in switching of the RF module.

Next, there is a method of scheduling an IPR in a non-power-saving mode. In the case of a WiFi infrastructure, there is no way to centrally control RF access, and thus, the arbitration module 230 cannot predict when an IPR will occur, and thus the WiFi module 210 in non-sleep mode. There is no way to schedule an IPR. On the other hand, in the case of WiMAX, since the central BS schedules all communication traffic on the network, the IPR of the WiMAX module 220 can be predicted from such scheduling information. An embodiment of predicting the IPR of the WiMAX module 220 in the non-sleep mode will be described with reference to FIG. 4.

4 illustrates a WiFi frame structure and a WiMAX frame structure according to an embodiment. Referring to FIG. 4, in a WiMAX time division duplex (TDD) mode, a frame starts with downlink (DL) and uplink (UL) map information, followed by a plurality of subframes. The WiMAX MAC 222 may determine whether there are unused subframes by decoding the map information, and if so, when it occurs. The arbitration module 230 may assign an unused WiMAX subframe to use for WiFi communication based on the information provided from the WiMAX MAC 222. This gives the WiFi module 210 an opportunity to access the common RF module 240 for every WiMAX frame, without delaying the transmission of other WiMAX traffic. In general, the frame period in the WiMAX network is about 5msec, the method according to the present embodiment can provide a rather short period of time for WiFi communication. However, as can be seen in Figure 4, the WiFi frame exchange sequence is relatively short, the WiFi communication can be completed within the unused subframe period of WiMAX. For example, if the 802.11g WiFi module 210 transmits data at a rate of 54 Mbps, a 1470 byte UDP packet may be transmitted within about 0.4 msec. This approach also has the advantage that there is no additional overhead for PHY resynchronization since the WiMAX module 220 regains access to RF within one frame.

As another embodiment of scheduling the IPR in the non-power-saving mode, there is a method using the MOB_SCN-REQ message of WiMAX. The WiMAX MAC 222 may use the MOB_SCN-REQ message to request the BS to provide a scanning interval of a certain length to find a nearby available BS. Upon receiving the MOB_SCN-REQ message, the BS may allocate the requested scanning interval and transmit a MOB_SCN-RSP message including start time information of the allocated interval. Since the WiMAX network module 220 temporarily stops data exchange with the BS during the interval allocated for scanning, the allocated interval can be used as the IPR of the WiMAX MAC 222. Since the WiMAX MAC 222 can specify the length of the scanning interval requested using the MOB_SCN-REQ, the user can control the length of the IPR. However, this embodiment has a disadvantage in that a load due to the exchange of MOB_SCN-REQ and MOB_SCN-RSP messages occurs whenever an IPR is assigned to the WiMAX MAC.

5 illustrates a finite state machine (FSM) for access control of an RF module. The arbitration module 230 switches between the cooperative mode and the competitive mode, and controls the access to the RF module 240 of the WiFi MAC 212 and the WiMAX MAC 222. The FSM of FIG. 5 describes the operation of the arbitration module 230 controlling the RF module 240. First, it is assumed that both the WiFi MAC 212 and the WiMAX MAC 222 do not occupy the RF module 240 (BOTH_OFF). At this time, if the WiFi MAC 212 requests the arbitration module 230 to occupy the RF module 240, the WiFi MAC 212 is capable of occupying the RF module 240, the state of the RF module 240 It becomes WF_ON. The WF_ON state refers to a state in which the WiFi MAC 212 is accessing the RF module 240 in the cooperative mode. In this state, if the WiFi MAC 212 transmits all the packets and disconnect the network by itself, the state of the RF module 240 is BOTH_OFF. On the other hand, the WiFi MAC 212 is to maintain the connection, but if the WiMAX MAC 222 needs to use the RF module 240 may take the RF occupancy (BOTH_ON_WM). For example, the WiMAX module 220 may take possession of the RF module 240 for BS scanning. BOTH_ON_WM indicates that the WiMAX MAC 222 is accessing the RF module 240 in the competitive mode. The BOTH_ON_WM state occupies the actual RF module 240 to perform packet transmission and reception without the WiMAX module 220 or the WiFi module 210 recognizing that the connection is lost. In the BOTH_ON_WM state, the wireless communication terminal 200 determines that both the WiFi module 210 and the WiMAX module 220 are connected to the network. Thus, it is possible to perform WiMAX scanning with WiFi connected. Once the WiMAX scanning is complete, the WiMAX MAC 222 returns the occupancy for the RF module 240 to the WiFi MAC 212. At this time, the state of the RF module 240 is WF_ON. When the WiFi MAC 212 returns the occupation of the RF module 240 in the WF_ON state, the state of the RF module 240 becomes BOTH_OFF.

Contrary to the above, if the WiMAX MAC 222 requests the arbitration module 230 to occupy the RF module 240 in the BOTH_OFF state, the WiMAX MAC 222, like the WiFi MAC 212, the RF module 240 In this case, the state of the RF module 240 is WM_ON. The WM_ON state means that the WiMAX MAC 222 is accessing the RF module 240 in the cooperative mode. In the WM_ON state, when the WiMAX MAC 222 disconnects the network, the state of the RF module 240 is BOTH_OFF. On the other hand, the WiMAX MAC 222 may maintain the network connection, but if the WiFi MAC 212 needs to use the RF module 240, the WiFi MAC 212 may take the RF occupancy (BOTH_ON_WF). For example, the WiFi module 210 may take possession of the RF module 240 for AP scanning. BOTH_ON_WF indicates that the WiFi MAC 212 is accessing the RF module 240 in the contention mode. The BOTH_ON_WF state occupies the actual RF module 240 to perform packet transmission / reception in a state in which the WiFi module 210 or the WiMAX module 220 does not recognize that the connection is lost. It is determined that both 210 and the WiMAX module 220 are connected to the network. Therefore, it is possible to perform WiFi scanning while WiMAX is connected. Once WiFi scanning is complete, WiFi MAC 212 returns the occupancy for RF module 240 to WiMAX MAC 222. At this time, the state of the RF module 240 is WM_ON. When the WiMAX MAC 222 returns the occupation of the RF module 240 in the WM_ON state, the state of the RF module 240 becomes BOTH_OFF. As described above, the RF module 240 switches states between BOTH_OFF, WF_ON, BOTH_ON_WM, WM_ON, and BOTH_ON_WF according to each event.

For the control of the RF module 240, the arbitration module 230 exchanges scheduling information such as IPR and BPR with the WiFi MAC 212 and the WiMAX MAC 222. In order to exchange such scheduling information, an API (Application Programming Interface) including event callback functions may be provided as a means for the WiFi MAC 212 and the WiMAX MAC 222 to communicate with the arbitration module 230. have. The WiFi MAC 212 and the WiMAX MAC 222 may request the mediation module 230 to access the RF module 240 using a callback function. The callback function used at this time may specify the RF access duration, priority, preemption. For example, the WiMAX MAC 222 may request the arbitration module 230 to occupy the RF module 240 or cancel the occupation. 212) Req_WiFi_RF_ON (use_level, use_time, ...,), Req_WiFi_RF_OFF, etc. are functions that request the mediation module 230 to occupy the RF module 240 or cancel the occupation. In addition, the WiFi MAC 212 and the WiMAX MAC 222 are provided with information about the occupancy state of the RF module 240 through the event callback function from the arbitration module 230. The callback function used at this time may specify whether the module occupying the RF is the WiFi module 210 or the WiMAX module 220. For example, if WiFi has acquired the RF module 240, ind_WiFi_Acquire_RF, if it releases the ind_WiFi_Release_RF, if WiMAX has acquired the RF module 240, ind_WiMAX_Acquire_RF, if the release is occupied ind_WiMAX_Release_RF Information can be provided.

6 is a view for explaining an RF module control method in the cooperative mode by way of example. In the cooperative mode, when one of the WiMAX MAC 222 and the WiFi MAC 212 (hereinafter, MAC 1) is in the IPR interval, the other MAC (hereinafter, MAC 2) is a common RF module 240 Gain access to After MAC 2 acquiring access to the RF module 240 transmits and receives data through the RF module 240, the MAC 2 releases the RF module 240 before the IPR interval of MAC 1 ends. Referring to FIG. 6, while the WiFi MAC 212 is an IPR, the WiMAX MAC 222 obtains access to the RF module 240. The period in which the WiMAX MAC 222 occupies the RF module 240 is indicated as T _WM , and the FSM state is WM_ON. The WiMAX MAC 222 then sends an RF de-occupancy request message (eg, Req_WiMAX_RF_Off) to the arbitration module 230 that it does not use the RF module 240 when it transitions from the BPR to the IPR. Receiving the message, the arbitration module 230 releases access to the RF module 240 of the WiMAX MAC 222. After the access is released, the RF module 240 until the WiFi MAC 212 or the WiMAX MAC 222 requests access to the RF module 240 again (that is, until the BPR interval of the WiFi or WiMAX starts). ) Nobody is occupied. After the WiMAX MAC 222 occupies the RF, the interval until the WiFi MAC 212 occupies the RF is indicated by T _MtoF , and the FSM state is BOTH_OFF. T _MtoF includes the time required to switch RF access between WiMAX MAC 222 and WiFi MAC 212, for example, may be about 300 μsec. When WiFi passes from the IPR to the BPR interval, the WiFi MAC 212 transmits an RF occupancy request message (eg, Req_WiFi_RF_ON) requesting the arbitration module 230 to access the RF module 240. The mediation module 230 that receives the message controls to access the RF module 240 of the WiFi MAC 212. The section in which the WiFi MAC 212 occupies the RF module 240 is indicated as T _WF , and the FSM state is WF_ON. Then, the WiFi MAC 212, like the WiMAX MAC 222, when the RF from the BPR to the IPR, RF de-request request message to the mediation module 230 does not use the RF module 240 (for example, Req_WiFi_RF_Off) Send it. The mediation module 230 receiving the message releases access to the RF module 240 of the WiFi MAC 212. After the access is released, the RF module 240 until the WiFi MAC 212 or the WiMAX MAC 222 requests access to the RF module 240 again (that is, until the BPR interval of the WiFi or WiMAX starts). ) Nobody is occupied. After the WiFi MAC 212 occupies the RF, the interval until the WiMAX MAC 222 occupies the RF is _denoted as T _FtoM , and the FSM state becomes BOTH_OFF again. T _FtoM includes the time required to switch RF access between WiFi MAC 212 and WiMAX MAC 222, for example, from about 300 μsec to several tens of msec. If the WiMAX PHY fails to re-gain access to the RF module 240 within one frame, because it requires additional time for the re-synchronization with the BS, T _FtoM requires a longer period of time than T _MtoF. T _Cycle represents the total time required for a sharing cycle in which the RF module 240 alternates between WiFi and WiMAX, and is calculated as T _WM + T _MtoF + T _WF + T _FtoM . As shown in the example of FIG. 6, when one IPR alternately includes another BPR, it is possible to operate in a cooperative mode. In the cooperative mode, both MACs alternately access RF to use both networks simultaneously. It is possible.

Meanwhile, while one MAC is still in the BPR interval, the other MAC may want to use the RF module 240. That is, since both MACs are BPR intervals, both MACs may request access to the RF module 240. In this case, the arbitration module 240 operates in a competitive mode. In the competitive mode, even if there is a MAC occupying the RF module 240 first, another MAC may bring the RF module 240 to occupy. Therefore, in the competitive mode, there is an advantage that the RF module 240 can be used immediately as needed before another MAC reclaims the occupation of the RF module 240. However, in a counterpart that is unable to transmit or receive all of the packets to be transmitted and received and is deprived of the RF module 240, a temporary packet transmission error may occur. The packet transmission error may be caused by various causes, such as when noise is generated or when a transmission signal is weak, in addition to the case where the occupation of the RF module 240 is lost. Since there are error recovery mechanisms for responding to any packet transmission error in the protocol of each layer, the wireless communication terminal 200 can use it to recover the packet transmission error.

In addition to this internal recovery mechanism, contention mode can provide the MAC with a non-preemptible period that ensures the accuracy of the exchange of critical data sensitive to packet transmission errors. The MAC occupying the RF module 240 in the non-empty section may continue to occupy the RF module 240 even if another MAC requests access to the RF module 240. According to an embodiment, the WiFi MAC 212 or the WiMAX MAC 222 may transmit the preemption possibility to the arbitration module 230 by including the RF occupancy request message. If you are sensitive to packet transmission errors, you may want to repeat the entire procedure if some packet transmissions fail. For example, the connection setup procedure, scan procedure, or hand. Handover procedure. In this section, it is necessary to prevent another MAC from intervening and occupying the RF module 240. When operating in the competitive mode, if a MAC in a non-preemptive interval informs the arbitration module 230 of the start and end of the non-empty interval, the arbitration module 230 accesses the RF module 240 during the non-preemptive interval. Can be prevented. For example, if the WiFi MAC 212 or the WiMAX MAC 222 attempts to transmit a general data packet that is not sensitive to the packet transmission flow, the preemptible is set to "preemptible" to transmit an RF occupation request message, and a packet transmission error If it is sensitive, the RF occupancy request message can be transmitted by setting preemption to "non-preemptible". If preemption is "preemptible", while the MAC occupies the RF module 240, another MAC may take possession of the RF module 240, and preemption is "non-preemptible". In this case, while the MAC occupies the RF module 240, another MAC whose preemption is "preemptible" cannot be taken away from the RF module 240. When both the WiFi MAC 212 and the WiMAX MAC 222 transmit an RF occupancy request message with preemptive availability, " non-preemptible, " 240 may be used continuously, and as another example, the high priority MAC included in the RF occupancy request message may be used to use the RF module 240. The priority included in the RF occupancy request message may be determined according to the sensitivity to packet transmission delay or packet transmission error. Priority information determined according to one embodiment is disclosed in FIG. 7. 7 is a table illustrating priorities according to packet types of WiFi and WiMAX.

8 is a diagram for explaining, for example, a method of controlling an RF module in a contention mode. In the example of FIG. 8, it is assumed that the WiFi scan occurred in the middle of the WiMAX BPR. Since the WiFi MAC 212 has generated data to transmit, the WiFi MAC 212 requests the arbitration module 230 to access the RF module 240. In addition, since the scanning procedure is sensitive to packet transmission error, the WiFi MAC 212 requests the arbitration module 230 for a non-preemptive interval (NON-PREEMPTIBLE) so that the WiMAX module occupies RF, while the WiMAX Prevents the module 220 from being robbed of RF occupancy. The arbitration module 230 temporarily reclaims the occupancy of the RF module 240 of the WiMAX at the request of the WiFi MAC 212, and allocates the RF module 240 to the WiFi MAC 212. Meanwhile, the WiMAX module 220 may interfere with WiMAX communication according to an unintentional occupation of the RF module 240 (Busy but blocked period). However, once the WiFi scan is complete, the WiMAX MAC 222 may regain access to the RF module 240 to resume WiMAX communication. For example, when the WiFi scan is complete, the WiFi MAC 212 sends an RF de-occupancy request message (eg, Req_WiFi_RF_Off) to the arbitration module 230 that it no longer uses the RF module 240. Upon receipt of the message, the arbitration module 230 sends an RF occupancy request message (eg, Ind_WiFi_Release_RF) to the WiMAX MAC 222 with information about it, and immediately transmits the occupancy for the RF module 230 to the WiMAX MAC 222. Pass) The WiMAX module 220 may resume communication with the other party and recover if a transmission error occurs while the RF is taken over.

Meanwhile, the occupancy period of the RF module 240 needs to ensure a minimum hold time so that the occupancy period of the RF module 240 can be maintained until one atomic operation is completed. In addition, it is necessary to limit the maximum turnaround time for occupying the RF module 240 in order to prevent any one MAC from occupying the RF module 240 too long. If one MAC continues to occupy the RF module 240, the connection of another module that does not occupy the RF module 240 may appear to be broken, or the throughput may be significantly lower due to continued packet retransmission.

9 is a flowchart illustrating a method of controlling RF access according to an embodiment of the disclosed technology. 9 illustrates a method in which a device supporting a wireless communication technology including a wireless LAN (WLAN) and a worldwide interoperability for microwave access (WiMAX) communicates using a common radio frequency (RF) module. The method of FIG. 9 corresponds to the present embodiment even when the wireless communication terminal 200 of FIG. 2 is implemented in time series. Therefore, the description of the wireless communication terminal 200 is applied to the present embodiment as it is. Descriptions overlapping with those described in FIG. 8 will be omitted.

In step S910, the arbitration module 230 receives an RF occupancy request message transmitted from at least one of the WiFi module 210 and the WiMAX module 220.

According to an embodiment, the WiFi module 210 or the WiMAX module 220 transmits an RF occupancy request message when there is a packet to transmit and receive. In this case, the RF occupancy request message may include an occupancy period, priority, or preemptive availability. According to another embodiment, when the WiFi module 210 or the WiMAX module 220 is in an idle state, the corresponding module transmits an RF release request message to the arbitration module 230. For example, the idle state of the WiFi module 210 or the WiMAX module 220 may include a state in which the WiFi module 210 or the WiMAX module 220 is in a sleep interval in a power saving (PS) mode. Can be. As another example, the idle state of the WiMAX module 220 may include a state in which the WiMAX module 220 is in an unallocated subframe period within a WiMAX frame. As another example, the idle state of the WiMAX module 220 may include a base station (BS) scanning interval of the WiMAX module 220.

In step S920, the arbitration module 230 determines a module to use the RF module 240 among the WiFi module 210 and the WiMAX module 220 based on the received message. According to an embodiment, the arbitration module 230 operates in a cooperative mode when the RF occupancy intervals requested by the WiFi module 210 or the WiMAX module 220 do not overlap, and the WiFi module 210 and the WiMAX are operated. When the RF occupancy intervals requested by the module 220 overlap, the module 220 operates in a competitive mode. In the cooperative mode, the arbitration module 230 uses a module that transmits an RF occupancy request message among the WiFi module 210 and the WiMAX module 220 and uses the RF module 240 during the period requested through the RF occupancy request message. Can be determined. In addition, in the cooperative mode, the arbitration module 230 may determine a module transmitting the RF occupancy request message as a module to use the RF module 240 within an idle period of the module that transmitted the RF release request message. have. In the competitive mode, the arbitration module 230, among the WiFi module 210 and the WiMAX module 220, the priority included in the RF occupancy request message transmitted by the WiFi module 210 and the RF transmitted by the WiMAX module 220 A module having a high priority value among the priorities included in the occupation request message may be determined as a module to use the RF module 240.

In step S930, the arbitration module 230 provides the RF module 240 with information about the module determined to use the RF module 240. When the information on the module to use the RF module 240 is provided, the RF module 240 transmits and receives packets of the module determined in the arbitration module 230 in step S940. That is, the RF module 240 transmits a packet provided from the module determined in the arbitration module 230 or provides the received packet to the module determined in the arbitration module 230.

In step S950, the arbitration module 230 provides the WiFi module 210 or the WiMAX module 220 with information about the module occupying the RF module 240. For example, the arbitration module 230 may provide the WiFi module 210 with information indicating that WiMAX occupies the RF module 240 or information indicating that WiMAX has released the RF module 240. On the other hand, the WiMAX module 220 may provide information indicating that the WiFi occupies the RF module 240 or that the WiFi releases the RF module 240.

10 is a graph comparing throughput of WiMAX and WiFi according to RF access time in cooperative mode. 10 is a result of performing a performance evaluation of the disclosed technology using a wireless communication terminal selectively using IEEE 802.16e Wave2 (WiMAX) and IEEE 802.11 b / g (WiFi). We evaluated the performance of each network module using IxChariot, which measures TCP throughput, and Iperf-Win32, which measures UDP throughput. Access to the RF module was alternated using the power saving modes of WiFi and WiMAX, and the throughput of both network modules was measured with TCP DL traffic. T _MtoF was set to 300μsec and T _FtoM was set to _4.7msec for stable resynchronization of the WiMAX PHY. Referring to the results of the graph of FIG. 10, it can be seen that the throughput of each network module is proportional to the RF access time T _WF , T _WM . This is because the longer the access time to the RF module 240, the larger the amount of packets can be transmitted.

11 is a graph illustrating transmission overhead in a contention mode. The graph of Figure 11 is for analyzing the efficiency of the competition mode, the test was made in the following environment. The WiFi module communicates with the AP in active mode. The WiMAX module interrupts every 200msec to access a common RF module. Thus, the WiFi MAC loses access to RF even when WiFi is in the BPR. WiMAX accesses RF for a while and then returns the RF back to WiFi. As such, Wi-Fi throughput in TCP DL traffic decreases as WiMAX temporarily accesses RF in contention mode. Due to the temporary RF access of the WiMAX module, WiFi loses its RF occupancy, so retransmission of packets can occur in the WiFi MAC. The longer the WiMAX MAC occupies RF, the average number of retransmissions of the WiFi MAC increases. If the number of retransmissions exceeds dotllLongRetryLimit or dotllShortRetryLimit, then the packet is discarded and throughput drops considerably near this threshold. Gray bars in FIG. 10 represent ideal throughput. Referring to FIG. 11, it can be seen that the throughput drop is proportional to the time WiMAX occupies RF. In Fig. 11, the black bars represent the throughput according to the actual experimental results. In FIG. 11, throughput appears to decrease dramatically when the WiMAX access time exceeds 30 msec. This is estimated to be due to the discarding of packets due to retransmission failure (takes about 30 msec) up to the retransmission limit number of times (16 times). Thus, if WiMAX occupies RF for less than the time that causes WiFi packet discard (eg, 30 msec), the overhead incurred in contention mode is negligible. The experimental results in FIG. 11 show that the disclosed technique can be implemented without particular difficulty and generates only an acceptable level of overhead.

While the system and apparatus disclosed herein have been described with reference to the embodiments shown in the drawings for purposes of clarity of understanding, they are illustrative only and various modifications and equivalent embodiments can be made by those skilled in the art. I will understand that. Accordingly, the true scope of protection of the disclosed technology should be determined by the appended claims.

Claims (18)

delete A device that supports wireless communication technologies, including Wireless LAN (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX), uses a common Radio Frequency (RF) module to communicate.
Receiving, by an arbitration module, an RF occupancy request message or an RF de-occupation request message transmitted from at least one of a WLAN module and a WiMAX module;
Determining, by the arbitration module, a module to use the RF module of the WLAN module and the WiMAX module based on the received message; And
The RF module transmitting a packet provided from the determined module, or providing the received packet to the determined module,
Wherein the receiving comprises:
Transmitting an RF occupancy request message when there is a packet to be transmitted or received by the WLAN module or the WiMAX module, and transmitting an RF release request message when the WLAN module or the WiMAX module is in an idle state. WLAN module and WiMAX module using a common RF module to communicate. The idle state of claim 2, wherein the WLAN module or the WiMAX module is idle.
The WLAN module and the WiMAX module including a state in which the WLAN module or the WiMAX module is in a sleep interval of a power saving (PS) mode, the communication using a common RF module. The idle state of the WiMAX module according to claim 2,
And a WiMAX module using a common RF module, wherein the WiMAX module comprises a state in which the WiMAX module is in an unallocated subframe period within a WiMAX frame. The idle state of the WiMAX module according to claim 2,
A WLAN module including a base station (BS) scanning interval of the WiMAX module and a WiMAX module communicate using a common RF module. A device that supports wireless communication technologies, including Wireless LAN (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX), uses a common Radio Frequency (RF) module to communicate.
Receiving, by an arbitration module, an RF occupancy request message or an RF de-occupation request message transmitted from at least one of a WLAN module and a WiMAX module;
Determining, by the arbitration module, a module to use the RF module of the WLAN module and the WiMAX module based on the received message; And
The RF module transmitting a packet provided from the determined module, or providing the received packet to the determined module,
The RF occupancy request message is a WLAN module and a WiMAX module, including the occupancy period, priority, or preemption whether the common RF module communicates. A device that supports wireless communication technologies, including Wireless LAN (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX), uses a common Radio Frequency (RF) module to communicate.
Receiving, by an arbitration module, an RF occupancy request message or an RF de-occupation request message transmitted from at least one of a WLAN module and a WiMAX module;
Determining, by the arbitration module, a module to use the RF module of the WLAN module and the WiMAX module based on the received message; And
The RF module transmitting a packet provided from the determined module, or providing the received packet to the determined module,
The determining step,
The WLAN module and the WiMAX module have a common RF that determines that the arbitration module transmits the RF occupancy request message among the WLAN module and the WiMAX module as a module to use the RF module during the request period through the RF occupancy request message. How to communicate using modules. A device that supports wireless communication technologies, including Wireless LAN (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX), uses a common Radio Frequency (RF) module to communicate.
Receiving, by an arbitration module, an RF occupancy request message or an RF de-occupation request message transmitted from at least one of a WLAN module and a WiMAX module;
Determining, by the arbitration module, a module to use the RF module of the WLAN module and the WiMAX module based on the received message; And
The RF module transmitting a packet provided from the determined module, or providing the received packet to the determined module,
In the determining step, the arbitration module,
If the RF occupied intervals requested by the WLAN module or the WiMAX module do not overlap, the device operates in a cooperative mode, and when the RF occupied intervals requested by the WLAN module and the WiMAX module overlap, a competitive mode is provided. Operating WLAN module and WiMAX module using a common RF module to communicate. The method of claim 8, wherein in the cooperative mode, the arbitration module,
The WLAN module and the WiMAX module use a common RF module to determine a module that transmits the RF occupancy request message as a module to use the RF module within an idle period of the module that transmits the RF release request message. How to communicate by. The method of claim 8, wherein in the contention mode, the arbitration module,
Among the WLAN module and the WiMAX module, a module having a higher priority value among the priority included in the RF occupancy request message transmitted by the WLAN module and the priority included in the RF occupancy request message transmitted by the WiMAX module. The WLAN module and the WiMAX module, which determine the module to use the RF module, communicate using a common RF module. A device that supports wireless communication technologies, including Wireless LAN (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX), uses a common Radio Frequency (RF) module to communicate.
Receiving, by an arbitration module, an RF occupancy request message or an RF de-occupation request message transmitted from at least one of a WLAN module and a WiMAX module;
Determining, by the arbitration module, a module to use the RF module of the WLAN module and the WiMAX module based on the received message;
Providing, by the arbitration module, the WLAN module or the WiMAX module with information about the module occupying the RF module; And
The RF module transmitting a packet provided from the determined module, or providing a received packet to the determined module, wherein the WLAN module and the WiMAX module communicate using a common RF module. delete WLAN module supporting Wireless LAN (WLAN) wireless communication technology;
A WiMAX module supporting Worldwide Interoperability for Microwave Access (WiMAX) wireless communication technology;
An RF module for transmitting a packet provided from the WLAN module or the WiMAX module or storing a received packet to the WLAN module or the WiMAX module; And
Receives an RF occupancy request message or an RF release request message transmitted from at least one of the WLAN module and the WiMAX module, and uses the RF module of the WLAN module and the WiMAX module based on the received message. It includes an arbitration module (Arbitrator) to determine the,
The WLAN module and WiMAX module,
A radio in which a WLAN module and a WiMAX module communicate with each other by using a common RF module, which transmits an RF occupancy request message when it is in a busy state, and transmits an RF release request message when it is in an idle state. Communication device. WLAN module supporting Wireless LAN (WLAN) wireless communication technology;
A WiMAX module supporting Worldwide Interoperability for Microwave Access (WiMAX) wireless communication technology;
An RF module for transmitting a packet provided from the WLAN module or the WiMAX module or storing a received packet to the WLAN module or the WiMAX module; And
Receives an RF occupancy request message or an RF release request message transmitted from at least one of the WLAN module and the WiMAX module, and uses the RF module of the WLAN module and the WiMAX module based on the received message. It includes an arbitration module (Arbitrator) to determine the,
The mediation module,
The WLAN module and the WiMAX module using the common RF module to determine a module that transmits the RF occupancy request message among the WLAN module and the WiMAX module as the module to use the RF module during the requested period through the RF occupancy request message. A wireless communication device that communicates. WLAN module supporting Wireless LAN (WLAN) wireless communication technology;
A WiMAX module supporting Worldwide Interoperability for Microwave Access (WiMAX) wireless communication technology;
An RF module for transmitting a packet provided from the WLAN module or the WiMAX module or storing a received packet to the WLAN module or the WiMAX module; And
Receives an RF occupancy request message or an RF release request message transmitted from at least one of the WLAN module and the WiMAX module, and uses the RF module of the WLAN module and the WiMAX module based on the received message. It includes an arbitration module (Arbitrator) to determine the,
The mediation module,
If the RF occupying intervals requested by the WLAN module or the WiMAX module do not overlap, the device operates in a cooperative mode, and when the RF occupying intervals requested by the WLAN module and the WiMAX module overlap, a competitive mode is provided. A wireless communication device in which an operating WLAN module and a WiMAX module communicate using a common RF module. The mediation module of claim 15, wherein the arbitration module in the cooperative mode comprises:
The WLAN module and the WiMAX module use a common RF module to determine a module that transmits the RF occupancy request message as a module to use the RF module within an idle period of the module that transmits the RF release request message. Wireless communication device for communication. The apparatus of claim 15, wherein in the contention mode the arbitration module is:
Among the WLAN module and the WiMAX module, a module having a higher priority value among the priority included in the RF occupancy request message transmitted by the WLAN module and the priority included in the RF occupancy request message transmitted by the WiMAX module. And a WLAN module and a WiMAX module, which determine the module to use the RF module, communicate using a common RF module. WLAN module supporting Wireless LAN (WLAN) wireless communication technology;
A WiMAX module supporting Worldwide Interoperability for Microwave Access (WiMAX) wireless communication technology;
An RF module for transmitting a packet provided from the WLAN module or the WiMAX module or storing a received packet to the WLAN module or the WiMAX module; And
Receives an RF occupancy request message or an RF release request message transmitted from at least one of the WLAN module and the WiMAX module, and uses the RF module of the WLAN module and the WiMAX module based on the received message. It includes an arbitration module (Arbitrator) to determine the,
The mediation module,
And a WLAN module and a WiMAX module for providing the WLAN module or the WiMAX module with information about a module occupying the RF module using a common RF module.

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