JP2009077402A - Method and apparatus for distributed service division based on wireless lan - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of dividing services of different priorities in a wireless network, and a mobile terminal. <P>SOLUTION: A mobile terminal includes: a transmission device which judges the type of a data frame to be transmitted and sets a corresponding duration value and an associated data type region in accordance with the type of the data frame and a quality status of a corresponding service within a wireless network; a frame type identifying apparatus for judging the type of a received frame; a network allocation vector timer apparatus which stores a network allocation vector of the present mobile terminal and updates the network allocation vector of the present mobile terminal based on a judgement result for the received frame type; and a reception device which receives a data frame transmitted from a terminal in the wireless network and updates a corresponding network allocation vector in accordance with the type of the received data frame and the quality status of a corresponding service in the wireless network. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

    The present invention relates to a method and apparatus for providing a service partition to a network telephone (VoIP) in a wireless network, and more specifically, a method and apparatus for realizing a distributed service partition by controlling a network allocation vector (NAV) in a wireless LAN. For example, when services with different priorities can be distinguished and there are many low-priority services in the network, the quality of high-priority services (eg, voice) can still be guaranteed.

  Providing a VoIP service in a wireless LAN is one of the very important services in a network. There are two basic problems with VoIP services in current wireless networks. First, the capacity that can be provided for the VoIP service of the wireless LAN is very limited. Further, when various services coexist in the wireless LAN, the VoIP service performance is severely degraded.

  The IEEE 802.11 standard defines a medium access control (MAC) layer and a physical layer feature for a wireless LAN (WLAN). Here, the MAC layer protocol includes a point coordination function (PCF, Point Coordination Function) for a contention-free stage (CFP) and a (CP, It defines a distributed cooperation function (DCF, Distributed Coordination Function) of Content Period.

  PCF provides a polling mechanism as a random access protocol technology, and realizes collision-free transmission by an access point polling all terminals within its communication range. In a communication environment without a more popular access point (AP), DCF adopts a carrier sense multiple access (CSMA / CA) method with a collision avoidance function. According to the CSMA / CA method, each terminal independently determines an access channel, and when access fails, the terminal shifts to a back-off process and accesses the channel again. The method further provides a flexible and effective self-organizing wireless communication protocol.

  In order to share the radio channel fairly and effectively between the independent terminals and reduce the collision of data packets, the DCF can transmit request packets / receive ready packets / data packets / response packets (RTS / CTS / DATA / ACK) based handshake process was defined and combined with a network allocation vector (NAV) set independently for each terminal to further enhance system performance. However, in an actual wireless LAN, DCF typically omits the RTS / CTS handshake operation by simplifying the handshake process to data packets / response packets (DATA / ACK).

  FIG. 1 shows a schematic diagram of the operation process of a DCF of the prior art. As shown in FIG. 1, when a terminal in a wireless network intends to transmit a packet as a source node, the terminal senses a channel. When sensing that the channel idle and idle time is equal to or greater than the DCF frame interval (DIFS) shown in FIG. 1, the terminal immediately transmits one data packet. Conversely, if channel busy is sensed when channel busy or channel idle time has not reached DIFS, the terminal waits until the channel idle and idle time is equal to the DCF frame interval (DIFS), and backoff ( Backoff) process is entered. After the back-off process ends, the terminal transmits the data packet. The data packet includes a transmitting terminal address (TA, Transmitter Address), a receiving terminal address (RA, Receiver Address), and a duration (Duration) necessary for the packet transmission. The duration value coincides with the sum of the time for transmitting one subsequent ACK packet and the time for transmitting one short frame interval (SIFS, Short Interframe Space). The receiving terminal as the destination node receives the data packet accurately and waits for one short frame interval (SIFS), and then feeds back and confirms one response packet (ACK, Acknowledgment).

  Furthermore, to avoid packet collisions between terminals, all non-destination receiving terminals that have successfully received the data packet in the transmitting terminal range store the current value and the duration value in the packet after receiving the data packet. The NAV value is compared. Based on the comparison result, the non-destination receiving terminal updates its stored NAV with a larger value, and all terminals promise to start radio channel access contention only when its NAV value is zero. In this manner, NAV is introduced, and packet access to other terminals in the communication range of the current communication terminal is suppressed by virtual reservation of radio resources. The method guarantees to some extent collisionless transmission of data packets.

  Because the IEEE 802.11 standard was designed for the transmission of as much data as possible in the wireless LAN, it is difficult to guarantee for services with different priorities, eg voice, video, or data are different services in the network. Quality is guaranteed. That is, the 802.11 standard cannot effectively guarantee the quality of a high-priority real-time service such as voice / video in the current wireless LAN.

  In order to solve the above problems, IEEE has submitted the 802.11e standard. This standard has been established to solve quality of service issues in wireless networks. 802.11e first defines quality-of-service (QOS) of wireless LAN, and is, for example, support for IP telephone (voice-over IP). In addition, the 802.11e standard defines a hybrid cooperative function (HCF). By replacing DCF and PCF with a new access scheme, HCF can provide improved access bandwidth and reduce high-priority communication delay. For DCF, 802.11e has extended the DCF function with an “extended distributed channel access” (EDCA) access method. For PCF, 802.11e extended the PCF function with the access method of “Hybrid Control Channel Access” (HCCA).

  Four types of access were specified by the EDCA method. Each of the various types corresponds to one type of data. Three parameters were placed for each access type. Cwmin indicates a minimum contention window, Cwmax indicates a maximum contention window, and AIFS indicates an arbitration frame transmission interval.

  In the application of DCF, a node having data to be transmitted has to wait until media idle to transmit the data.

  FIG. 2 shows the operation process of a prior art EDCA according to the 802.11e standard. As shown in FIG. 2, a transmitter attempting to transmit data waits for unnecessary time. The unnecessary time length is determined by the type of data to be transmitted. The AIFS value set for such a data access type defines an unnecessary waiting time.

  For voice access type data, the AIFS value should be set small to reduce delay and ensure high priority communication. For mail and FTP type data, the AIFS value should be set large. Voice services require short delay times. A small AIFS value means that voice data can start the next stage of network contention faster than insensitive communications.

  After the AIFS time period has elapsed, the nodes participating in channel contention generate one random backoff delay, which is related to CWmin and CWmax. A lower CWmin and lower CWmax should be set for high priority access types. A specific method for setting the back-off delay is Backoff = Uniform (0, CW), where Uniform (0, CW) is a random number uniformly distributed between 0 and CW, and CW is CWmin, CWmax, And is determined by the number of packet retransmissions.

  However, DCF and EDCA still have problems in terms of supporting wireless LAN service partitioning. For DCF, originally designed for data services, the performance of high priority services (eg, voice) is severely reduced when there is a small amount of low priority data service traffic in the network.

  Also, for EDCA, the service classification problem was solved by setting different AIFS and back-off windows, but the setting of back-off windows is random, so if there are many low-priority services in the network, high priority Services still cannot be effectively guaranteed.

  The present invention provides a method and apparatus for distinguishing services with different priorities in a wireless LAN, sets different duration values for different service packets on the transmitter side, and based on different service types on the receiver side By making different updates to the network allocation vector, if there are many low priority services, solve the high priority service quality degradation problem, improve the system high priority service capacity, and excellent backward Realized compatibility.

  According to one aspect of the present invention, a mobile terminal that classifies services having different priorities in a wireless network, determines a type of a data frame to be transmitted, and determines a data frame type and a corresponding service in the wireless network. Stores a transmission device that sets a corresponding duration value and a related data type area according to the quality status in the frame, a frame type identification device that determines the type of the received frame, and a network allocation vector of the mobile terminal. A network allocation vector timer device that updates the network allocation vector of the mobile terminal based on a determination result for the received frame type, a data frame transmitted from the terminal in the wireless network, and a type of the received data frame and corresponding Service wireless network Depending on the quality condition in provides a mobile terminal including a receiving device to update the relevant NAV.

  According to another aspect of the present invention, there is provided a method for distinguishing services having different priorities in a wireless network, the step of determining whether a packet to be transmitted by a mobile terminal is a high priority packet, and a high priority Setting a subtype field in the media access control (MAC) head of the packet to indicate that the packet to be transmitted is a high priority packet; and a duration field of the MAC head of the high priority packet The method includes the steps of: setting a duration original time required to transmit the value to a value obtained by adding a priority increment, and transmitting a packet having an updated duration field.

  According to still another aspect of the present invention, there is provided a method for distinguishing services having different priorities in a wireless network, in which a mobile terminal determines whether a packet to be transmitted is a high priority packet, Setting the UP region in the media access control (MAC) head of the priority packet to indicate that the packet to be transmitted is a high priority packet; and the duration region of the MAC head of the high priority packet A method is provided that includes setting a duration original time required to transmit a packet to a value obtained by adding a priority increment, and transmitting a packet with an updated duration field.

  According to still another aspect of the present invention, a method for receiving services of different priorities in a wireless network, the method comprising: reading a subtype region in a network allocation vector head of a new received data frame; Determining whether the frame is a high priority packet; if the received data frame is a high priority packet; determining a value of priority increment P; subtracting the priority increment from the duration value Updating a network allocation vector stored in the terminal with the value.

  According to still another aspect of the present invention, a method for receiving services with different priorities in a wireless network, the method comprising reading an UP region or a subtype region in a network allocation vector head of a received new data frame; Determining whether the received data frame is a high priority packet; if the received data frame is a high priority packet; setting a value of priority increment P; and determining the priority from the duration value Updating a network allocation vector stored in the terminal with a value minus the increment.

  According to the present invention, a high priority service (for example, voice) is connected to a network with many low priority services (for example, quality as much as possible) by realizing the classification of services having different priorities by controlling the network allocation vector in the wireless LAN. Even if there is a data service that guarantees service quality, the service quality is sufficiently guaranteed.

  Also, according to the present invention, for a terminal transmitting a high priority service, a terminal transmitting a low priority service has to wait more time before channel contention, and its unnecessary waiting time. In addition, all the terminals transmitting high priority services in the network can complete one packet transmission.

  The method and apparatus of the present invention has backward compatibility because only the NAV setting and updating method is changed. Also, since these changes are made only at the high priority service terminal, it is compatible with the prior art 802.11 network or 802.11e network.

  The above and other objects and novel features of the present invention will become more fully apparent when the following description of the embodiments is read in light of the accompanying drawings as follows.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In order not to disrupt the understanding of the present invention, details and functions not necessary for the present invention are omitted.

  Hereinafter, a mobile terminal that classifies services with different priorities according to an embodiment of the present invention will be described. FIG. 3 shows an embodiment of a mobile terminal that classifies services with different priorities.

  As shown in FIG. 3, the mobile terminal according to the present invention includes a transmitting device 100, a receiving device 200, a network allocation vector (NAV) timer device 300, and a frame type recognition device 400. The transmission device 100 includes a transmission storage device 101, a channel access device 102, and a transmission device 103. The receiving device 200 includes a channel sensing device 201, a receiving device 202, and a reception processing device 203.

  According to the present invention, the mobile terminal may still adopt the basic random access control process of DCF. Before transmitting data, the transmitting terminal first determines the type of data frame. Thereafter, a corresponding duration value and a related data type field are set according to the type of the data frame and the quality status of the type service in the network. On the receiving terminal side, the corresponding network allocation vector is updated according to the type of the received data frame and the quality status of the type service in the wireless network.

  Specifically, in the transmission device 100, the transmission storage device 101 stores data packets from higher layers. When a data packet to be transmitted arrives at the transmission storage device 101, the transmission storage device 101 first determines the type of the packet. Thereafter, the transmission storage device 101 packages the data packet according to a corresponding method to form a data frame (DATA frame) and provides the data frame to the channel access device 102. The channel access device 102 determines whether the transmitting terminal can access the channel. For example, the channel access device 102 adopts the CSMA / CA protocol according to the 802.11 DCF or 802.11e EDCA standard and determines whether the current channel access of the terminal is permitted. When the channel access device 102 instructs that the channel access condition is satisfied, the transmission device 103 transmits a DATA frame.

  When the mobile terminal receives a DATA frame from another node in the wireless network, the reception processing device 203 indicates that the DATA frame has been successfully received, and the receiving terminal address (RA) area of the DATA frame and the terminal When they are the same, an ACK frame is transmitted.

  The channel sensing device 201 included in the receiving device 200 senses a channel in the wireless network when the mobile terminal does not transmit a data packet. When channel busy is sensed, the receiver 202 is started to prepare for data reception.

  The receiving device 202 receives data from the wireless channel and transmits the received data to the reception processing device 203 to make a determination. The reception processing device 203 determines whether the data packet has been successfully received and determines the type of the received data packet. Also, the reception processing device 203 instructs the operation of the next step based on the processing result. Specifically, if the reception processing device 203 succeeds in receiving the DATA packet and it is determined that the terminal address matches the address indicated by the RA area of the DATA packet, the transmission device 103 is started and the ACK packet is transmitted. Prepare to send. If the reception processing device 203 succeeds in receiving the DATA packet, but it is determined that the address of the terminal does not match the address indicated by the RA area of the DATA packet, the type area and the duration area of the DATA packet are stored as data. Transfer to frame type identification device 400. If the reception processing device 203 succeeds in receiving the ACK packet and it is determined that the terminal address and the address indicated by the RA area of the ACK packet match, it is determined whether the value of the duration field of the ACK packet is zero. To detect. If the value in the duration field is zero, it indicates that the transmission has been completed. If it is not zero, the transmission apparatus 103 is set as a star to prepare for transmission of the subsequent data packet segment. If the reception processing device 203 has successfully received the ACK packet, but it is determined that the address of the terminal does not match the address indicated by the RA region of the ACK packet, the data frame type identification device 400 determines the duration region of the ACK packet. Forward to.

  The frame type identification device 400 determines the frame type provided by the reception processing device 203, and updates the NAV stored in the mobile terminal based on the frame type and the frame duration. If the received frame is a management frame, the frame type identification device 400 notifies the NAV timer device 300 that the NAV is updated according to the original duration of the frame. If the received frame is a data frame, the frame type identification device 400 determines whether the frame is a high priority frame or a low priority frame based on the type region of the data frame. Thereafter, the frame type identification device 400 notifies the NAV timer device 300 of the determination result, and performs a corresponding update on the NAV based on the determination result from the NAV timer device 300.

  The NAV timer device 300 stores a network allocation vector (NAV) and updates the NAV based on the determination result for the received frame provided from the frame type identification device 400. In addition, since a single terminal can simultaneously support a high priority service and a low priority service, the NAV timer apparatus 300 needs to have different NAV timers for the high priority service and the low priority service.

  FIG. 4 shows a flowchart of an example of a method for distinguishing services with different priorities according to an embodiment of the present invention. In this example, a basic random access control process of DCF may be adopted. Before the transmitting terminal transmits a data frame, it first determines the type of the data frame, and sets the corresponding duration value and related data type field according to the type of data frame and the quality status of the type service in the network. To do.

That is, before the transmitting terminal transmits data, the data frame type identification device in the terminal must first identify the type of the upper layer packet. Thereafter, the corresponding area in the data frame is set based on the identification result. For example, in an 802.11 MAC frame, the duration field indicates the duration for transmitting the current frame. When setting the duration according to the type of data frame, O represents the duration original time required for frame transmission, and P can be set to represent a priority increment that distinguishes the priority of the frame. Here, P has three setting methods. (1) P = 0, (2) P = CW _{max_high_priority} * TimeSlot, (3) P = T, where CW _{max_high_priority} is the maximum contention window for high priority services, and TimeSlot is the time slot length of the wireless LAN Yes, T is the packet generation interval of the high priority service. Since high priority services are typically real-time services, this type of service typically has a fixed packet generation interval.

  Hereinafter, a process in which the transmitting terminal classifies services having different priorities will be described with reference to FIG. First, in step S401, the frame type identification device 400 determines whether an upper layer packet to be transmitted is a high priority packet. If it is a high priority packet, the flow moves to step S402, and a subtype area in the MAC head of the packet is set to indicate that the packet to be transmitted is a high priority packet. For example, in such a case, the value of the subtype area may be set to “1000”. After that, in step S403, the MAC head duration area of the high priority packet is set to “O + P”, that is, a value obtained by adding the priority increment to the duration original time required to transmit the packet. Next, the packet with the updated duration area is transmitted in step S404.

  On the other hand, if it is determined in step S401 that the packet to be transmitted is not a high priority packet, the flow proceeds to step S405. For example, in such a case, the value may be set to “1000” in the subtype area. Thereafter, in step S406, the MAC head duration field of the packet to be transmitted is set to “O”, and the process proceeds to step S404 to transmit the packet.

FIG. 5 shows a flowchart of another example of a method for distinguishing services with different priorities according to an embodiment of the present invention. In the example, an access control process according to the 801.11e standard may be employed. Before the transmitting terminal transmits a data packet, the data frame identification device in the terminal first identifies the type of the upper layer packet. Thereafter, the corresponding area in the frame is set based on the identification result. Here, the duration field indicates a duration required to transmit the current frame. For example, in an 802.11e MAC frame, the duration field indicates the duration required to transmit the current frame. When setting the duration according to the type of the data frame, O represents the duration original time required for frame transmission, and P represents the priority increment that distinguishes the priority of the frame. Here, P has three setting methods. (1) P = 0, (2) P = CW _{max_high_priority} * TimeSlot, (3) P = T, where CW _{max_high_priority} is the maximum contention window for high priority services, and TimeSlot is the time slot length of the wireless LAN Yes, T is the packet generation interval of the high priority service. Since high priority services are typically real-time services, this type of service typically has a fixed packet generation interval.

  A process in which the transmitting terminal classifies services having different priorities will be described with reference to FIG. First, in step S501, the transmission storage device of the transmission terminal sets the UP area of the MAC head according to the packet type. The UP area is an area defined by the 802.11e standard and represents a data frame type, that is, whether the data frame has a high priority or a low priority. The UP area and the duration area are independent from each other. Thereafter, in step S502, the frame type identification device 400 determines whether the upper layer packet to be transmitted is a high priority packet. If it is a high-priority packet, the flow moves to step S503, where the duration field of the MAC head of the high-priority packet is set to “O + P”, that is, the original time required to transmit the packet. By setting the priority increment to a value that is added, and when other terminals in the network receive the high priority packet, update the stored NAV with the duration with the priority increment added, thereby updating the high priority packet Guarantees the transmission of Next, in step S504, the packet whose duration area is updated is transmitted.

  On the other hand, if it is determined in step S502 that the packet to be transmitted is not a high-priority packet, the flow moves to step S505, and sets the duration field of the MAC head of the packet to be transmitted to “O”. In step S504, the packet is transmitted.

  FIG. 6 shows a flow for adjusting the priority increment P according to the high priority service quality status detected by the mobile terminal. An access point (AP: Access Point) in the wireless LAN indicates a high-priority service quality status in the downlink direction and a high-priority service quality status in the uplink direction that can be detected by each terminal in the network by using a beacon frame. Can be recognized. The terminal obtains the final service quality status according to the worst service quality status in the downlink direction and the uplink direction, and based on the obtained result, the terminal performs priority increment P according to the steps shown in FIG. Set the value.

As shown in FIG. 6, the quality status of the high priority service is detected in step S601. Thereafter, in step S602, it is determined whether the quality status of the high priority service is good. If the quality status of the high priority service is good, the flow moves to step S603, and the value of the priority increment P is set to “0”. If the quality status of the high priority service is bad in step S602, the flow moves to step S604 to determine whether the quality status of the high priority service is relatively good. If the quality status of the high priority service is relatively good, the flow moves to step S605 and sets the value of the priority increment P to “CW _{max_high_priority} * TimeSlot”. If the decision result in the step S604 is NO, the flow moves to a step S606 and sets the value of the priority increment P to “T”.

  FIG. 7 shows a flow of an example of a processing process executed when a terminal in the network receives a packet transmitted from the transmitting terminal. In FIG. 7, the processing process executed after the receiving terminal receives the data frame will be described taking 802.11 wireless LAN as an example. First, in step S701, it is determined whether the terminal has received a new data frame. If no new data frame has been received, the terminal is still in the sensing state. If a new data frame is received in step S701, the flow moves to step S702 to read the subtype area in the MAC head. Thereafter, in step S703, it is determined whether the received data frame is a high priority packet based on the read subtype region. That is, it is determined whether the value of the subtype is “1000”. If it is determined that the data frame received in step S703 is a high priority packet, the flow executes step S704 to set the value of the priority increment P. Thereafter, in step S705, "duration value -P" is used, where the duration value represents a numerical value given from the duration area of the received data frame, and "duration value -P" is calculated from the numerical value in the duration area. It represents what subtracted. The NAV stored in the terminal is updated with the obtained value. On the other hand, if the decision result in the step S703 is NO, the flow moves to a step S706 to update the NAV stored in the terminal with the duration value.

  In the process, the receiving terminal needs to make a judgment on the exact value of P. There are three types of methods for determining the value taken by P.

Method (a): Since the typical duration (L) of CW _{max_high_priority} , TimeSlot, T and the high priority service data frame is known in advance, the receiving terminal can perform P determination only by performing section determination on the received Duration value. Can be determined. Here, the typical duration L indicates the time actually required for one high priority packet to complete transmission in the network. If the received duration value is greater than L and less than L + T, it is determined that P = CW _{max_high_priority} * TimeSlot, and if the received duration value is less than or equal to L, it is determined that P = 0, and the received duration If the value is equal to or greater than L + T, it is determined that P = T.

  Method (b): The transmitting node sets the value type of P using an empty bit in the data frame control area. After other nodes receive this data frame, specific values are determined by reading the corresponding bits.

  Method (c): AP transmits control information to the corresponding node by beacon, and notifies the value of P. After receiving the control information, the transmitting node sets P according to a corresponding instruction when transmitting data. The other nodes determine the value of P and perform corresponding settings for the NAV after receiving the radio frame according to an instruction from the AP.

  FIG. 8 shows another example of a flow executed when a terminal in the network receives a packet transmitted from a transmitting terminal. FIG. 8 illustrates a processing process executed after the receiving terminal receives a data frame, taking 802.11e wireless LAN as an example. The distinction between FIG. 8 and FIG. 7 is that the receiving terminal determines whether the received data frame is a high priority packet by reading the UP area in the MAC head. Specifically, first, in step S801, it is determined whether the terminal has received a new data frame. If no new data frame has been received, the terminal continues to maintain the sensing state. If a new data frame is received in step S801, the flow moves to step S802 to read the UP area in the MAC head. Thereafter, in step S803, it is determined whether the received data frame is a high priority packet based on the read UP area. That is, it is determined whether the value of the UP area is “111”. If it is determined that the data frame received in step S803 is a high priority packet, the flow moves to step S804 to determine the value of the priority increment P. Thereafter, in step S805, "duration value -P" is used, where the duration value represents a numerical value given from the duration area of the received data frame, and "duration value -P" is calculated from the value of the duration area. Represents minus P. The NAV stored in the terminal is updated with the obtained value. On the other hand, if the decision result in the step S803 is NO, the flow moves to a step S806 to update the NAV stored in the terminal with the duration value.

  FIG. 9 shows an example of performing NAV updating based on the data packet type in the wireless LAN according to the present invention. FIG. 9 illustrates a NAV update operation when a data frame transmitted from a transmission terminal is received using an 802.11 wireless LAN as an example. Assume that there are one AP and three terminals in the wireless LAN, where terminal A and terminal B are voice terminals, terminal C is a data terminal, and terminals C and AP are existing network devices. Terminal A transmits a voice packet to the AP. Before transmitting the voice packet, the terminal A first determines the status of the voice service in the current network, and then determines the value of the priority increment P. Next, terminal A sets the duration area of the MAC frame bearing the voice packet to L + P. After the voice packet is transmitted from the terminal A, it is received by the AP, the terminal B, and the terminal C. By determining the address of the voice packet, the AP determines that the packet has been transmitted to itself. Thus, the AP processes voice packets according to the 802.11 standard without changing the NAV. After receiving the voice packet, terminal B reads the subtype area and determines that the received packet is a voice packet. Next, after determining the specific value of P by analyzing the duration value, the NAV is set to the duration value −P, where the duration value represents the numerical value of the duration field of the received data frame, "Time value -P" represents a value obtained by subtracting P from a numerical value in the duration area. Terminal C is a conventional data terminal, and after receiving a voice packet, updates the NAV to duration according to the provisions of the 802.11 standard.

  FIG. 10 shows another example of performing NAV update based on the data packet type in the wireless LAN according to the present invention. FIG. 10 illustrates an NAV update operation when a data frame transmitted from a transmission terminal is received using an 802.11e wireless LAN as an example. Within an existing 802.11e wireless LAN, usually, one terminal may support multiple parallel services with different priorities.

  As shown in FIG. 10, terminal A simultaneously supports voice service and data service, terminal B is a single voice terminal, terminal C is a single data terminal, and AP simultaneously supports voice service and data service. Assume that terminal C and AP are existing network devices. Since terminal A supports multiple services, it is necessary to maintain a list that records NAV values for different services. Terminal B transmits a voice packet to the AP. Before sending the voice packet, terminal B first determines the status of the voice service in the current network, and then determines the value of priority increment P. Next, terminal B sets the duration area of the MAC frame bearing the voice packet to L + P. After the voice packet is transmitted from the terminal B, it is received by the AP, the terminal A, and the terminal C. By determining the destination address of the voice packet, the AP determines that the packet has been transmitted to itself. Thus, the AP processes the voice packet according to the 802.11e standard without changing the NAV. After receiving the voice packet, terminal A reads the UP area and determines that the received packet is a voice packet. Next, a specific value of P is determined by analyzing the duration value, the NAV corresponding to the voice service is updated to duration-P, and the NAV corresponding to the data service is updated to duration. Terminal C is a conventional data terminal, and after receiving the voice packet, updates the NAV to duration according to the provisions of the 802.11e standard.

  FIG. 11 shows another example in which the NAV update is performed based on the data packet type in the wireless LAN according to the present invention. FIG. 11 illustrates a NAV update operation when a data frame transmitted from a transmission terminal is received using an 802.11e wireless LAN as an example. Within the 802.11e wireless LAN, there are some free bits in the radio frame bearing the service to indicate the value of P for this frame.

As shown in FIG. 11, in the 802.11e wireless LAN, terminal A and terminal B are single voice terminals, terminal C is a single data terminal, and AP supports voice service and data service at the same time. Assume C and AP are existing network devices. The terminal B transmits a voice packet to the AP, and first determines the status of the voice service in the current network before transmitting the voice packet, and then determines the value of the priority increment P. Next, terminal B sets the duration area of the MAC frame bearing the voice packet to L + P. Thereafter, terminal B sets the seventh and eighth bits of the QoS Control field of the MAC frame to values corresponding to P (for example, bit 00 is P = 0, bit 01 is P = CW _{max_high_priority} * TimeSlot, and bit 10 is P = T). After the voice packet is transmitted from the terminal B, it is received by the AP, the terminal A, and the terminal C. By determining the destination address of the voice packet, the AP determines that the packet has been transmitted to itself. Thus, the AP processes the voice packet according to the 802.11e standard without changing the NAV. After receiving the voice packet, terminal A reads the UP area and determines that the received packet is a voice packet. Next, the specific value of P is determined by the seventh and eighth bits of the QoS Control area of the received MAC frame, and the NAV is updated to duration-P. Terminal C is a conventional data terminal, and after receiving a voice packet, updates the NAV to duration in accordance with the provisions of the 802.11e standard.

  FIG. 12 shows another example of performing NAV update based on the data packet type in the wireless LAN according to the present invention. FIG. 12 illustrates a NAV update operation when a data frame transmitted from a transmission terminal is received using an 802.11e wireless LAN as an example. In the 802.11e wireless LAN, the AP notifies a specific value of P to the terminal by transmitting specific information by Beacon.

  As shown in FIG. 12, within the 802.11e wireless LAN, terminal A and terminal B are single voice terminals, terminal C is a single data terminal, AP supports voice service and data service simultaneously, and terminal C And the AP is an existing network device. Terminal B transmits a voice packet to the AP. The AP measures the voice service quality in the uplink and downlink directions, determines the situation of the voice service in the current network, and then the AP writes the determined value of P in a dedicated information area, and the Beacon To the voice terminal in the network. After receiving the information area, terminal B reads the value of P, and then sets the duration area of the MAC frame bearing the voice packet to L + P. After the voice packet is transmitted from the terminal B, it is received by the AP, the terminal A, and the terminal C. The AP processes voice packets according to the 802.11e standard without changing the NAV. After receiving the voice packet, terminal A reads the UP area and determines that the received packet is a voice packet. Next, the NAV is updated to duration-P by P instructed from the received AP. Terminal C is a conventional data terminal, and after receiving the voice packet, updates the NAV to duration according to the provisions of the 802.11e standard.

  The method and apparatus for distinguishing high priority services such as voice have been described above using 802.11 and 802.11e wireless LANs as examples. The present invention is not limited to the two types of wireless LANs described above, and can be applied to other wireless networks.

  So far, preferred embodiments of the present invention have been described. It should be understood by those skilled in the art that various modifications, replacements and additions can be made without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should not be understood as being limited to the specific embodiments described above, but is limited only by the scope of the appended claims.

FIG. 1 is a schematic diagram of an operation process of a distributed cooperative function (DCF) according to the prior art. FIG. 2 is a schematic diagram of an operation process of Enhanced Distributed Channel Access (EDCA) according to the prior art. FIG. 3 is a block diagram of a mobile terminal that can classify services with different priorities according to an embodiment of the present invention. FIG. 4 is a flowchart of a method for classifying services with different priorities according to an exemplary embodiment of the present invention. FIG. 5 is a flow chat of a method for distinguishing services with different priorities according to another embodiment of the present invention. FIG. 6 is a flowchart for adjusting the priority increment P according to the service quality situation in which the mobile terminal is detected. FIG. 7 is a flowchart of an example of a processing process executed when a data frame according to the present invention is received. FIG. 8 is a flowchart of another example of a processing process executed when a data frame is received according to the present invention. FIG. 9 is a schematic diagram of an example of performing NAV update based on the data packet type in the wireless LAN according to the present invention. FIG. 10 is a schematic diagram of another example in which NAV updating is performed based on the data packet type in the wireless LAN according to the present invention. FIG. 11 is a schematic diagram of another example in which NAV updating is performed based on the data packet type in the wireless LAN according to the present invention. FIG. 12 is a schematic diagram of still another example in which NAV updating is performed based on the data packet type in the wireless LAN according to the present invention.

Claims (41)

A mobile terminal that classifies services with different priorities in a wireless network,
A transmitting device that determines the type of data frame to be transmitted and sets a corresponding duration value and an associated data type field according to the type of data frame and the quality status of the corresponding service in the wireless network;
A frame type identification device for determining the type of the received frame;
A network allocation vector timer device that stores a network allocation vector (NAV) of the mobile terminal and updates the network allocation vector of the mobile terminal based on a determination result for a received frame type;
Receiving a data frame transmitted from a terminal in a wireless network, and updating a corresponding network allocation vector according to the type of the received data frame and the quality status of the corresponding service in the wireless network. Mobile terminal. The transmitting device is
A storage device for storing data packets from higher layers, determining the type of data packet, and packaging the data packet into a data frame;
A channel access device for determining whether the mobile terminal can access a radio channel and transmit a data frame;
The mobile terminal according to claim 1, further comprising: a transmission device that transmits a packaged data frame. The receiving device is
A channel sensing device that senses a channel in a wireless network when the mobile terminal does not transmit a data packet, and starts a receiving device and prepares for data reception when sensing channel busy;
A receiving device that receives data from a wireless channel, transmits the received data to a reception processing device, and makes a determination;
The mobile terminal according to claim 1, further comprising: a reception processing device that determines whether the reception of the data packet is successful and determines a type of the received data packet.   When the reception processing apparatus receives a data frame and indicates that the terminal is a transmission destination of the data frame, the reception processing apparatus starts and prepares to transmit an acknowledgment (ACK) packet. The mobile terminal according to claim 3.   When the reception processing apparatus receives a data frame but indicates that the terminal is not the transmission destination of the data frame, the reception processing apparatus transfers the data frame type area and the duration area to the data frame type identification apparatus. The mobile terminal according to claim 3, wherein   When the reception processing device receives an acknowledgment (ACK) packet and indicates that the terminal is a transmission destination of the ACK packet, the reception processing device detects whether the value of the duration field of the ACK packet is zero. The mobile terminal according to claim 3, wherein   When the reception processing apparatus receives an acknowledgment (ACK) packet but indicates that the terminal is not the transmission destination of the ACK packet, the reception processing apparatus transfers the duration field of the ACK packet to the frame type identification apparatus. The mobile terminal according to claim 3.   When the frame type identification device determines that the received frame is a management frame, the frame type identification device notifies the network assignment vector timer device that the network assignment vector is updated according to the original duration of the frame. The mobile terminal according to claim 1.   When the frame type identification device determines that the received frame is a data frame, the frame type identification device further determines whether the data frame is a high priority frame or a low priority frame, and the determination result is assigned to the network. The mobile terminal according to claim 1, wherein the mobile terminal notifies the vector timer device and performs a corresponding update on the network allocation vector based on the determination result by the network allocation vector timer device.   When the received data frame is a high-priority packet, the value of the priority increment P is determined, and the determined priority increment P is subtracted from the duration value in the received data frame. The mobile terminal according to claim 9, wherein the stored network allocation vector is updated. If the value of the duration field of the received radio frame is larger than the typical duration L and smaller than the value obtained by adding the packet generation interval T of the high priority service to L (ie, L + T), P = CW _{max_high_priority} * TimeSlot. And
If the value of the duration field of the received radio frame is less than or equal to L, it is determined that P = 0,
If the value of the duration field of the received radio frame is equal to or greater than L + T, it is determined that P = T,
The mobile terminal according to claim 10, wherein the typical duration L indicates a time actually required for one high priority packet to complete transmission in the network.   The transmitting node sets the value of the priority increment P using an empty bit in the data frame control area, and the other nodes read the corresponding bit after receiving the data frame and read the value of P The mobile terminal according to claim 9, wherein the mobile terminal is determined.   The access point notifies the value of the priority increment P by transmitting control information to a node in the network by a beacon signal, and the transmitting node receives P when receiving high priority data after receiving the control information. And the corresponding duration is set based on the selected P value, and the other nodes receive the high priority frame based on the control information notified from the access point, The mobile terminal according to claim 9, wherein the network assignment vector is updated by determining a value.   The mobile terminal according to claim 9, wherein when the received data frame is not a high priority packet, the network allocation vector stored in the terminal is updated with a duration value in the received data frame.   The mobile terminal according to any one of claims 1 to 14, wherein the wireless network is a wireless LAN. A method of distinguishing services with different priorities in a wireless network,
Determining whether the packet to be transmitted by the mobile terminal is a high priority packet;
Setting a subtype region in the media access control (MAC) head of the high priority packet to indicate that the packet to be transmitted is a high priority packet;
Setting the duration field of the MAC head of the high priority packet to a value obtained by adding the priority increment to the duration original time required to transmit the packet;
Transmitting a packet whose duration field has been updated.   17. The method of claim 16, further comprising setting a duration field of a MAC head of the packet to a duration original time required to transmit the packet when the packet to be transmitted is not a high priority packet. The method described in 1.   The method according to claim 16, further comprising the step of adjusting the priority increment P according to the quality status of the high priority service detected by the mobile terminal.   The method according to claim 18, further comprising the step of setting a value of the priority increment P to "0" when the quality status of the high priority service is good. Further comprising setting the value of the priority increment P to “CW _{max_high_priority} * TimeSlot” when the quality status of the high priority service is relatively good,
_19. The method of claim 18, wherein CW _{max_high_priority} is a maximum contention window for a high priority service, and TimeSlot is a time slot length in the wireless LAN. If the value of the received duration field is larger than the typical duration L and smaller than the value obtained by adding the packet generation interval T of the high priority service to L (ie, L + T), it is determined that P = CW _{max_high_priority} * TimeSlot. 21. The method of claim 20, wherein: Further comprising setting the value of priority increment P to “T” if the quality status of the high priority service is relatively poor,
19. The method of claim 18, wherein T is a high priority service packet generation interval.   23. The method of claim 22, wherein if the received duration value is greater than or equal to the typical duration L plus T, then P = T.   The method of claim 18, further comprising: determining that P = 0 if the received duration value is less than or equal to the typical duration L.   The transmitting node sets the value of the priority increment P using the vacant bits in the data frame control area, and the other nodes determine the value of P by the corresponding bits after receiving the data frame. The method of claim 18, further comprising the step of:   The access point notifies the value of the priority increment P by transmitting control information to the corresponding node by a beacon signal, and the transmitting node sets the value of P when transmitting data after receiving the control information. The other nodes further include a step of determining a value of P and updating a network allocation vector after receiving a frame based on control information notified from an access point. The method described. A method of distinguishing services with different priorities in a wireless network,
The mobile terminal determining whether the packet to be transmitted is a high priority packet;
Setting the UP region in the medium access control (MAC) head of the high priority packet to indicate that the packet to be transmitted is a high priority packet;
Setting the duration field of the MAC head of the high priority packet to a value obtained by adding the priority increment to the duration original time required to transmit the packet;
Transmitting a packet whose duration field has been updated.   28. The method of claim 27, further comprising setting a duration field of a MAC head of the packet to a duration original time required to transmit the packet when the packet to be transmitted is not a high priority packet. The method described.   The method according to claim 27, further comprising the step of adjusting the priority increment P according to the quality status of the high priority service detected by the mobile terminal.   30. The method of claim 29, further comprising the step of setting the value of the priority increment P to "0" when the quality status of the high priority service is good.   31. The method of claim 30, wherein if the received duration field value is less than or equal to the typical duration L, it is determined that P = 0. Further comprising setting the value of the priority increment P to “CW _{max_high_priority} * TimeSlot” when the quality status of the high priority service is relatively good,
_30. The method of claim 29, wherein CW _{max_high_priority} is a maximum contention window of a high priority service, and TimeSlot is a time slot length in a wireless LAN. If the value of the received duration field is larger than the typical duration L and smaller than the value obtained by adding the packet generation interval T of the high priority service to L (ie, L + T), it is determined that P = CW _{max_high_priority} * TimeSlot. 35. The method of claim 32. Further comprising setting the value of priority increment P to “T” if the quality status of the high priority service is relatively poor,
30. The method of claim 29, wherein T represents a packet generation interval for a high priority service.   35. The method of claim 34, wherein if the received duration value is greater than or equal to the typical duration L plus T, then P = T.   The transmitting node sets the value of the priority increment P using the vacant bits in the data frame control area, and after receiving the data frame, the other nodes read the corresponding bits and set the value of P. 30. The method of claim 29, further comprising the step of determining.   The access point notifies the value of the priority increment P by transmitting the control information to the corresponding node by a beacon signal, and the transmitting node sets the value of P when transmitting the data after receiving the control information. The other nodes further include a step of determining a value of P and updating the network allocation vector after receiving the frame based on the control information notified from the access point. The method described. A method for receiving services with different priorities in a wireless network,
Reading the subtype region in the network allocation vector head of the received new data frame;
Determining whether the received data frame is a high priority packet;
Determining the value of priority increment P if the received data frame is a high priority packet;
Updating the network allocation vector stored in the terminal with a value obtained by subtracting the priority increment from the duration value.   39. The method of claim 38, wherein if the received data frame is not a high priority packet, the network allocation vector stored in the terminal is updated with a duration value. A method for receiving services with different priorities in a wireless network,
Reading the UP field or subtype field in the network allocation vector head of the received new data frame;
Determining whether the received data frame is a high priority packet;
If the received data frame is a high priority packet, setting a value of priority increment P;
Updating the network allocation vector stored in the terminal with a value obtained by subtracting the priority increment from the duration value value;
A method comprising the steps of:   41. The method of claim 40, wherein if the received data frame is not a high priority packet, the network allocation vector stored in the terminal is updated with a duration value.

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