KR20150007966A - Method of service discoveryin wireless personal area networks - Google Patents

Abstract

Disclosed is a service discovery method for a wireless personal area network. The present invention relates to a service discovery method performed on a terminal for performing passive scanning for searching for a specific service based on whether to receive a frame including a specific service identifier on a MAC layer of the terminal and performing active scanning for broadcasting a service discovery request frame for searching for the specific service in the case of failed specific service search. Therefore, the present invention is able to efficiently search for whether to operate a target service and a wireless frequency channel on a physical layer and a medium access control layer without help of an upper layer.

Description

≪ Desc / Clms Page number 1 > METHOD OF SERVICE DISCOVERY IN WIRELESS PERSONAL AREA NETWORKS &

The present invention relates to wireless personal communication network technology, and more particularly, to a service discovery method capable of minimizing power consumption in a wireless personal communication network.

Due to the diversification of the personal wireless communication market, there is a growing demand for using various application services together in the same wireless personal communication network. Accordingly, in a service provider that provides a communication terminal and an organization that standardizes a communication standard, an attempt has been actively made to provide a service having different requirements by using a multi-radio interface.

However, in order for a communication terminal to use a specific service in a network environment as described above, it is required to search whether or not a service provided in the network exists and whether a specific service is currently used.

In the conventional wireless personal communication network system, specifications of a physical layer and a medium access control layer are defined to provide a specific service domain. In order to access a network providing a corresponding service, Scan function.

However, such a network scan function is restricted to a function of searching only for the presence or absence of a specific wireless network defined by a network operator, and thus there is a problem in that it can not be applied to a wireless communication network system that provides various kinds of services over various frequency bands.

 Also, even if the search for a specific service is performed, if the communication terminal does not know the actual operating radio channel frequency of the service currently provided in the network, wireless communication can not be practically performed.

Accordingly, there is a need for a method that enables a terminal to efficiently search for services and operating frequency channels in a wireless personal communication network environment that provides multiple services across multiple frequency bands or multiple wireless channels.

It is an object of the present invention to solve the above problems and provide an apparatus and method for searching for an operation target radio service channel and an operation radio frequency channel in a transport layer without supporting an upper layer in a wireless personal communication network environment providing multiple services, And to provide a service discovery method capable of searching for a target service and an operation frequency channel while minimizing the service discovery.

According to another aspect of the present invention, there is provided a service discovery method for a wireless personal communication network, the method comprising the steps of: Performing a passive scan for searching for a specific service based on whether the specific service is received or not, and if the search for the specific service fails, the MAC layer performs an active scan for broadcasting a service discovery request frame for searching for the specific service .

The step of performing the passive scan may further include the steps of the MAC layer receiving a scan request primitive including a service ID and a channel ID from an upper layer and transmitting the scan request primitive to the MAC layer based on the service ID and the channel ID. The method comprising the steps of: updating a service identifier and a channel identifier of a service discovery response command frame or a service discovery acknowledgment command frame of the service discovery response command frame; and, when a service discovery response command frame or a service discovery notification command frame is transmitted from the physical layer, Comparing a service identifier with a service identifier of the MAC layer; and comparing a service identifier included in the service discovery response command frame or a service discovery notification command frame and a service identifier If a match is found, there is the MAC layer may include a step to notify the higher layer that the service discovery response command frame or the service discovery notify command frame is received.

Here, the MAC layer may perform the passive scan for a time determined based on the reception time of one Basic Repetition Block (BRB) and the number of basic repetition blocks.

The step of performing the passive scan may include passing the passive scan result to the upper layer through a scan acknowledgment primitive.

Here, the service discovery method may include a step of connecting to a personal area network (PAN), in which the terminal provides the specific service, when the specific service is searched for by performing the manual scan, And performing channel sampling (CS) during an attempt to access the personal communication network.

The step of performing the active scanning may include the steps of: receiving a service discovery request primitive in which the MAC layer indicates active scanning from an upper layer; receiving, by the MAC layer, a service discovery request primitive corresponding to the received service discovery request primitive; The method comprising: broadcasting the service discovery request command frame after generating a command frame; and receiving, when the MAC layer receives a service discovery response command frame from another terminal during a predetermined response waiting time, Determining whether the service identifier of the MAC layer matches the service identifier of the MAC layer when the service identifier included in the service discovery response frame matches the service identifier of the MAC layer; And sending a service discovery acknowledgment primitive to the upper layer indicating that a response frame has been received.

Herein, the step of transmitting the service discovery acknowledgment primitive to an upper layer may include the step of the MAC layer generating a service discovery notification command frame and broadcasting the service discovery acknowledgment command frame.

Here, the step of performing the active scan may not transmit a service discovery request command frame waiting for transmission for a service search if the service identifier included in the service discovery response frame matches the service identifier of the MAC layer .

If the service discovery response command frame is not received from another terminal during the response waiting time, the service discovery method repeatedly broadcasts the service discovery request command frame until the preset maximum retransmission number is not exceeded And transmitting a primitive indicating that the active scan has failed to the upper layer if the service discovery response command frame is not received until the preset maximum retransmission number is exceeded.

Here, the service discovery method may include activating the receiver of the terminal only in a channel sampling period included in the channel sampling period, according to a preset channel sampling period, when the search of the specific service fails as a result of performing the active scan, And performing channel sampling to monitor reception of the discovery request command frame.

The step of performing the channel sampling comprises the steps of: receiving a channel sampling request primitive instructing the MAC layer to perform channel sampling from the upper layer; and transmitting the channel sampling request primitive to the MAC layer, Updating a basic repetition block number and a channel sampling interval to a basic repetition block number and a channel sampling interval value included in the channel sampling request primitive; and transmitting, by the MAC layer, the reception of the service discovery request command frame in the channel sampling interval And monitoring.

The step of performing channel sampling further includes the step of, when the service discovery request command frame is not received during the channel sampling interval, the MAC layer deactivating the receiver of the terminal and waiting until the next channel sampling period can do.

The step of performing channel sampling may include comparing a service identifier included in the received service discovery request command frame and a service identifier of the MAC layer when the service discovery request command frame is received during the channel sampling interval And transmitting a service discovery indication primitive indicating that the service discovery request command frame is received to an upper layer when the service identifier included in the received service discovery request command frame matches the service identifier of the MAC layer can do.

The step of performing channel sampling may include receiving a service discovery response primitive from the upper layer in response to the service discovery indication primitive transmitted from the upper layer by the MAC layer, Generating a response command frame, and broadcasting the generated service discovery response command frame.

According to another aspect of the present invention, there is provided a service discovery method for a wireless personal communication network, the method comprising: receiving a service discovery request command frame from another terminal; If the service identifier included in the received service discovery request command frame is the same as the service identifier of the MAC layer of the terminal, the service discovery request primitive instructing the MAC layer to receive the service discovery request command frame is transmitted to the upper layer Wherein the MAC layer receives a service discovery response primitive from the upper layer and the MAC layer generates a service discovery response command frame and the generated service discovery response command And a step of broadcasting the frame.

The service discovery method includes the steps of receiving a service discovery notification command frame from another terminal after broadcasting the service discovery response command frame and transmitting the service discovery notifying command frame to the service discovery server through the service identifier of the MAC layer , The MAC layer may transmit a notification indication primitive indicating reception of a service discovery notification command frame to an upper layer.

According to another aspect of the present invention, there is provided a service discovery method for a wireless personal communication network, the method comprising: The method comprising the steps of: performing a passive scan for searching for a specific service based on whether or not a frame is received; and if the MAC layer succeeds in searching for the specific service, And activating a receiver of the terminal to perform channel sampling for monitoring reception of a service discovery request command frame.

According to another aspect of the present invention, there is provided a method for performing service discovery for a wireless personal communication network, the method comprising: setting a backoff count value; Performing a clear channel assessment (CCA), confirming reception of a basic repetition block (BRB) during a first time when the channel status is busy, Identifying a type of a received frame based on information included in the basic repetition block and performing processing of a basic repetition block corresponding to a type of the received frame when the basic repetition block is received for a first time period .

The step of performing the processing of the basic repetition block may include determining a type of a received frame based on a SFD (Start Frame Delimiter) of the basic repetition block, and when the received frame is a service discovery request frame, The terminal deactivates the receiver for a specific time based on the number of basic repetition blocks indicated by the header of the received frame, activates the receiver after the lapse of the specified time to reduce the backoff count value, If the received service discovery response frame is a service discovery response frame, if the service identifier included in the received service discovery response frame is the same as the service identifier of the MAC layer of the terminal, In the case of the frame, the received service discovery notification If the service identifier included in the frame is the same as the service identifier of the MAC layer of the terminal, the communication channel identifier of the MAC layer is updated to the communication channel identifier contained in the received service discovery notification frame, have.

Here, the service discovery method may further include, independently of performing the channel state check, decreasing the backoff count value until the set backoff count value has a predetermined value, and decreasing the backoff count value every time the backoff count value is decreased Performing a backoff counting procedure of waiting for a predetermined number of unit backoff count times while the receiver of the terminal is deactivated.

According to the service discovery method for a wireless personal communication network as described above, there is provided a method of searching for an operation target service and an operation radio frequency channel in a transport layer (physical layer and medium access control layer) without the help of an upper layer .

In the present invention, each terminal transmits a service discovery request command frame having the same long period, thereby omitting the time synchronization procedure between the terminals, thereby reducing the complexity of the system.

In addition, according to the present invention, by providing an optimized CSMA-CA algorithm for service discovery in a network in which many terminals exist, the service discovery delay time due to the retransmission of the command frame can be reduced.

In addition, by performing a channel sampling (CS) process for the discovered terminal, the service discovery of other terminals is possible while minimizing power consumption of the terminal.

In addition, the service life and the network lifetime of the UE can be maximized by reducing the service discovery delay time and reducing the power consumption due to channel sampling.

In the present invention, the processing complexity of the terminal can be lowered through the operations as described above, and the service discovery can be efficiently performed by minimizing the power consumed by the terminal in searching for the service.

1 shows a state transition diagram of a MAC layer for low power service discovery.
2 is a message flow chart illustrating the manual LESD scan procedure shown in FIG.
3 is a message flow diagram illustrating the active LESD scan procedure shown in FIG.
4 is a message flow diagram illustrating the channel sampling procedure shown in FIG.
5 is an exemplary diagram for explaining channel sampling.
6 shows the format of the LESD request command.
7 shows the format of the LESD response command.
8 shows the format of the LESD notification command.
Figures 9a and 9b show the MLSDE-LESD-SCAN.request primitive.
Figures 10A and 10B show the MLSDE-LESD-SCAN.confirm primitive.
11A and 11B show the MLSDE-LESD.request primitive.
12A and 12B show the MLSDE-LESD.indication primitive.
13A and 13B show the MLSDE-LESD.response primitive.
14A and 14B show the MLSDE-LESD.confirm primitive.
15A and 15B show the MLSDE-LESD-NOTIFY.indication primitive.
16A and 16B show the MLSDE-LESD-CS. Request primitive.
17A and 17B show the MLSDE-LESD-CS.confirm primitive.
18 is a flow chart illustrating a serial CSMA-CA procedure for low power service discovery.
19 is a flow chart illustrating a parallel CSMA-CA procedure for low power service discovery.
20 is a flowchart illustrating a backoff counting procedure performed in the parallel CSMA-CA process shown in FIG.
21 shows a structure of a physical layer frame.
22 shows an example of the SFD used in the LESD.
23A and 23B show physical layer headers.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

The contents not specifically described in the embodiments of the present invention described below can be supported by a standard (for example, IEEE 802.15) created by organizations performing technical standardization of a wireless personal communication network.

First, terms used in this specification are defined as follows.

CS: Channel Sampling

BRB: Basic Repetition Block (basic repetition block)

LESD: Low Energy Service Discovery (Low Power Service Discovery)

LIFS: Long Inter Frame Spacing

MAC: Medium Access Control (MAC)

MHR: MAC Header (MAC header)

MLME: MAC sublayer Management Entity (MAC sublayer management element)

MLSDE: MAC sublayer Service Discovery Entity (MAC sublayer service discovery element)

PAC: Peer Aware Communication

PAN: Personal Area Network (Personal Communication Network)

PD: PAC Device (Peer-to-peer communication terminal)

PLME: PHY layer Management Entity (Physical Layer Management Element)

SFD: Start frame delimiter

PIB: PAN information base (PAN information base)

WPAN: Wireless Personal Area Network

The service discovery method according to an embodiment of the present invention includes a medium access control (MAC) for low energy service discovery (hereinafter, referred to as LESD) ) Layer technology and physical (PHY) layer technology.

First, the MAC layer technology for LESD will be described.

1 shows a state transition diagram of a MAC layer for low power service discovery. 2 is a message flow diagram illustrating the manual LESD scan procedure shown in FIG.

Hereinafter, a manual LESD scan operation will be described with reference to FIGS. 1 and 2. FIG.

Manual LESD scanning (110)

A peer-aware communication device (PD) with a macLESDenbaled value set to TRUE for LESD is subjected to a passive LESD scan process for the first time based on the MLSDE-LESD-SCAN.request primitive.

The next layer (NHL) 210 of the MAC layer generates the MLSDE-LESD-SCAN.request primitive to proceed with a passive scan to check whether there is a service indicated by the ServiceID for the physical channel set to the LESDChannelID To the MLSDER (MAC sublayer Service Discovery Entity) 220 (S201).

When receiving MLSDE-LESD-SCAN.request primitive from an upper layer (210), MLSDE (220) of the terminal MAC PIB (PAN information base) attribute (attribute) of the macServiceID MLSDE-LESD-SCAN.request of primitive ServiceID Parameter, updates the macAvailableChannelID with the value of the AvailableChannelID parameter of the MLSDE-LESD-SCAN.request primitive, and then performs a manual LESD scan (S202).

When a frame is received during the manual scan, the physical layer checks whether it is a LESD response command frame or a LESD notification command frame based on a start frame delimiter (SFD) of a received frame. If the frame does not correspond to the command frame, The received frame is ignored without proceeding to decoding.

When the physical layer receives the frame including the valid SFD (LESD response or LESD notification command frame) and transmits the frame to the MLSDE 220, the MLSDE 220 checks whether the value of the Service ID field of the received frame matches the macServiceID . At this time, if the Service ID field value of the frame does not match the macServiceID frame is ignored, and if it matches MLSDE (220) informs the reception of the command frame to the upper layer 210, through the primitive according to the type of the received command frame .

That is, when the received frame is the LESD response command frame (S203), the MLSDE 220 reports it to the upper layer 210 via the MLSDE-LESD.confirm (S204). If the received frame is the LESD notification command frame (S205), it reports to the upper layer 210 through the MLSDE-LESD-NOTIFY.indication primitive (S206).

On the other hand, the terminal proceeds to the manual LESD scan 110 for up macNumBRB ㅧ _BRB T time (S202). Here, T _BRB is a time required for receiving one basic repetition block (BRB), and macNumBRB is an attribute value indicating the number of BRBs. Here, the BRB includes a synchronization header (SHR) and a physical layer header (PHR) header of a physical layer frame, and the SHR may include a preamble and a start frame delimiter (SFD) 21).

Upon completion of the manual LESD scan, the MLSDE 220 of the terminal transmits the scan result to the upper layer 210 using the MLSDE-LESD-SCAN.confirm primitive (S207).

If the terminal succeeds in finding the PAC (Peer Aware Communication) service and the physical channel used by the service through the manual scan, the upper layer of the UE generates a MLME-ASSOCIATE primitive and transmits the corresponding PAN Area Network) (PAN subscription state 140 of FIG. 1). While the UE is attempting to access the PAN, the MLSDE is notified via the MLSDE-LESD-CS.request primitive to transition from the upper layer to the channel sampling (CS) 130 state.

Alternatively, if the terminal fails to find the PAC service to be searched through the manual scan and the physical channel used by the service, the terminal transitions to the active LESD scan (step 120 of FIG. 1) Go ahead.

Active LESD scan (120)

3 is a message flow diagram illustrating the active LESD scan procedure shown in FIG.

Hereinafter, an active LESD scan operation will be described with reference to FIGS.

If the terminal does not find the PAC service through the manual LESD scan 110, the terminal performs an active LESD scan to find the corresponding service.

The upper layer (NHL) 310 issues the MLSDE-LESD.request primitive to the MLSDE 320 to start the active LESD scan (S301).

Upon receiving the MLSDE-LESD.request primitive from the upper layer 310, the MLSDE 320 generates a LESD request command and transmits the LESD request command frame using a CSMA-CA (Carrier Sense Multiple Access-Collision Avoidance) (S302).

The MLSDE 330 of the peripheral terminal that has received the broadcast LESD request command frame checks whether the value of the Service ID field of the received command frame matches the macServiceID, and ignores the received command frame if it does not match.

Alternatively, when the value of the Service ID field of the received command frame is equal to macServiceID , the MLSDE 330 of the neighboring terminal reports to the upper layer 340 that a LESD request command frame broadcast through the MLSDE-LESD.indication primitive has been received (S303).

Upon receipt of the MLSDE-LESD.indication primitive, the upper layer 340 of the neighboring terminal sends an MLSDE-LESD.response primitive to the MLSDE 330 in response thereto (S304).

Upon receiving the MLSDE-LESD.response primitive from the upper layer 340, the MLSDE 330 of the neighboring terminal generates a LESD response command frame and broadcasts it using the CSMA-CA algorithm (S305).

The MLSDE 320 of the terminal receiving the broadcasted LESD response command frame checks whether the value of the Service ID field of the received command frame matches the macServiceID, and ignores the received command frame if it does not match.

Or, MLSDE (320) is LESD a higher layer (310) if the Service ID field value of a command frame is received matches the macServiceID, updates the value in macCommunicationChannelID CommunicationChannelID parameter value of the received frame and through MLSDE-LESD.confirm primitive response command frame is received (S308).

At the same time, the MLSDE 320 generates a LESD notification command and broadcasts it using the CSMA-CA algorithm (S306). This informs surrounding terminals again that there is a corresponding service.

When MLSDE (330) of the peripheral terminal receives the LESD notification command frame ensure that the Service ID field value of a command frame is received matches the macServiceID, it matches, updating the macCommunicationChannelID value to CommunicationChannelID parameter value of the received frame and MLSDE-LESD It notifies the upper layer 340 via the -NOTIFY.indication that the LESD notification command has been received (S307).

When the LESD response command including the same service or the LESD notification command is received, the terminals that want to find the same service discover the service. If the service is found, the LESD request The command frame is not transmitted. This can reduce frame collisions due to unnecessary frame transmission in the channel.

If the MLSDE 320 does not receive the LESD response command or the LESD notification command indicating the service to be searched for during the maximum response wait time macLESDResponseWaitTime, which is the maximum response wait time, the MLSDE 320, after broadcasting the LESD request command frame (S302) The MACNumLESDRequestRetries parameter indicating the number of LESD request retransmissions can be incremented by one and the LESD request command can be retransmitted using the CSMA-CA algorithm if the incremented value does not exceed the parameter macMaxLESDRequestRetries, which indicates the maximum number of LESD request retransmissions.

If the increased macNumLESDRequestRetries value exceeds the macMaxLESDRequestRetries value, the MLSDE 320 sets the Status parameter value of the MLSDE-LESD-SCAN.confirm primitive to EXCEED_NUM_TRIAL, and the active LESD scan is successfully completed (S309).

If the terminal does not successfully find the PAC service through the active LESD scan process, the upper layer may issue a MLME-START primitive to attempt to start a new PAN (PAN start state 150 of FIG. 1). The MS attempts to initiate a new PAN while the MLSDE is notified via the MLSDE-LESD-CS.request primitive to transition from the upper layer to the channel sampling (CS) state 130.

In the channel sampling process 130,

4 is a message flow diagram illustrating the channel sampling procedure shown in FIG. 5 is an exemplary diagram for explaining channel sampling.

Hereinafter, the active LESD scan operation will be described with reference to FIGS. 1, 4, and 5. FIG.

The channel sampling (CS) process can reduce the power consumed by the service discovery of the UE.

The upper layer 410 generates an MLSDE-LESD-CS.request primitive for channel sampling and transmits it to the MLSDE 420 (S401).

Upon receiving the MLSDE-LESD-CS.request primitive from the upper layer 410, the MLSDE 420 starts a channel sampling process. In addition, the MLSDE 420 transmits an MLSDE-LESD-CS.confirm primitive to the upper layer 410 in response to the received MLSDE-LESD-CS.request primitive (S402).

MLSDE (420) is when MLSDE-LESD-CS.request receives the primitive sets the macLESDdone to TRUE, and updates the value to macNumBRB and macCSDuration MLSDE-LESD-CS.request NumBRB parameters of the primitive and CSDuration parameter values. As shown in FIG. 5, the terminal listens for a channel during the macCSDuration time in a macNumBRB x (T _BRB + T _LIFS ) time period (CS Interval). Where T _LIFS represents LIFS (Long Inter Frame Spacing) time. During the macCSDuration time, the terminal waits to receive the LESD request command frame including the service ID field matching the macServiceID value. If the LESD request command frame is not received during the macCSDuration time, the terminal turns off the receiver and waits until the next period (CS Interval).

On the other hand, when the MLSDE 420 receives the LESD request command frame during the macCSDuration time (S403), the MLSDE 420 checks whether the value of the Service ID field of the received command frame matches the macServiceID, and ignores the received command frame.

Or MLSDE (420) reports that the received LESD request command frame to the upper layer (410) Service ID field values through, MLSDE-LESD.indication primitive if the match macServiceID of a command frame is received (S404).

Upon receiving the MLSDE-LESD.indication primitive from the MLSDE 420, the upper layer 410 issues an MLSDE-LESD.response primitive to the MLSDE 420 in response to the MLSDE-LESD.indication primitive (S405).

Upon receiving the MLSDE-LESD.response primitive from the upper layer 410, the MLSDE 420 generates a LESD response command frame and broadcasts a LESD response command frame using the CSMA-CA algorithm (S406).

Hereinafter, the MAC command frame will be described in more detail.

LESD request command

6 shows the format of the LESD request command.

The LESD request command is used by the terminal to request the neighboring terminal using the service to find the existence of the service and the physical channel number being used.

The MHR (MAC Header) field of the LESD request command may include a Service ID and an Available Channel ID field.

The Service ID field may be composed of one octet and represents a service identification number (ID number) that the terminal desires to find. The value of the Service ID field is set to the ServiceID parameter value of the MLSDE-LESD.request primitive received from the upper layer.

The Available Channel ID field may comprise one octet and represents a list of physical channel numbers available at the terminal. The value of the Available Channel ID field is set to the value of the AvailableChannelID parameter of the MLSDE-LESD.request primitive received from the upper layer.

LESD response command

7 shows the format of the LESD response command.

The LESD respond command is used by the terminal to respond to the LESD request command.

The MHR field of the LESD respond command may include a Service ID field and a Communication Channel ID field.

The Service ID field may consist of one octet and represents the service ID value in the wireless PAN to which the terminal is connected. The value of the Service ID field is set to the ServiceID parameter value of the MLSDE-LESD.response primitive received from the upper layer.

The Communication Channel ID field may be composed of one octet and indicates a list of available physical channel numbers in the terminal. The value of the Communication Channel ID field is set to the value of the AvailableChannelID parameter of the MLSDE-LESD.request primitive received from the upper layer.

LESD notification command

8 shows the format of the LESD notification command.

The LESD notification command is used to notify the neighboring terminals of the service discovery result corresponding to the LESD response command received by the terminal.

The MHR field of the LESD notification command may include a Service ID field and a Communication Channel ID field.

The Service ID field may be composed of one octet, and indicates a service identification number (Identification Number) being used. The value of the Service ID field is set to the value of the Service ID field of the received LESD response command.

The Communication Channel ID field may comprise one octet and represents a list of operating channels used for service. The value of the Communication Channel ID field is set to the value of the Communication Channel ID field of the received LESD response command.

Hereinafter, the MAC primitive will be described in more detail.

MLSDE-LESD-SCAN.request primitive

FIG. 9A shows the structure of the MLSDE-LESD-SCAN.request primitive, and FIG. 9B shows the parameters of the MLSDE-LESD-SCAN.request primitive.

The MLSDE-LESD-SCAN.request primitive is generated by an upper layer and forwarded to MLSED, which serves to inform the user to initiate a manual LESD scan.

As shown in FIGS. 9A and 9B, the MLSDE-LESD-SCAN.request primitive may include NumBRB, ServiceID, LESDChannelID, and AvailableChannelID parameters.

The NumBRB parameter indicates the number of times the Basic Repetition Block (BRB) is repeated.

The ServiceID parameter indicates the PAC service ID that the terminal desires to find.

The LESDChannelID parameter indicates the channel number used for the service search.

The AvailableChannelID parameter indicates a list of channel numbers available in the terminal.

After receiving the MLSDE-LESD-SCAN.request primitive from the upper layer, the MLSDE of the MS updates the macLESDChannelID , macServiceID and macAvailableChannelID values with the LESDChannelID, ServiceID, and AvailableChannelID parameter values of the MLSDE-LESD-SCAN.request primitive, respectively.

Since, MLSDE advances the passive scanning for a given channel over the macLESDChannelID for up macNumBRB × _BRB T time. Where T _BRB is the time taken to receive a Basic Repetition Block (BRB). After the MLSDE completes the scan, it sends the scan results to the upper layer using the MLSDE-LESD-SCAN.confirm primitive.

MLSDE-LESD-SCAN.confirm primitive

FIG. 10A shows the structure of the MLSDE-LESD-SCAN.confirm primitive, and FIG. 10B shows the parameters of the MLSDE-LESD-SCAN.confirm primitive.

The MLSDE-LESD-SCAN.confirm primitive is used by MLSDE to report the results of manual scans to higher layers.

As shown in FIGS. 10A and 10B, the MLSDE-LESD-SCAN.confirm primitive may include a Status parameter.

The Status parameter indicates the result status for a manual LESD scan request. Depending on the scan result, values such as SUCCESS, SCAN_IN-PROGRESS, INVALID_PARAMETER, and NO_SERVIC_FOUND can be set.

If the MLSDE receives a LESD response command or a LESD notification command that includes a Service ID parameter that matches the macServiceID during the manual LESD scan, the MLSDE generates a primitive containing the Status parameter, Report receipt. For example, when receiving a command or response LESD LESD notification command including the Service ID parameter that matches macServiceID and the timer is turned off for manual scanning, MLSDE is a Status parameter value of MLSDE-LESD-SCAN.confirm primitive to SUCCESS And notifies the upper layer that the passive scan is completed.

Otherwise, if the terminal does not receive a LESD response command or a LESD notification command containing a Service ID parameter that matches the macServiceID until the timer is released, the MLSDE shall set the Status parameter value of the MLSDE-LESD-SCAN.confirm primitive to NO_SERVICE_FOUND And informs the upper layer of the scan result.

Alternatively, if the MLSDE receives the MLSDE-LESD-SCAN.request primitive from the upper layer while the scan is in progress, the MLSDE sets the Status parameter value of the MLSDE-LESD-SCAN.confirm primitive to SCAN_IN_PROGRESS to inform the upper layer

MLSDE-LESD.request primitive

FIG. 11A shows the structure of the MLSDE-LESD.request primitive, and FIG. 11B shows the parameters of the MLSDE-LESD.request primitive.

The MLSDE-LESD.request primitive is used to generate the LESD request command for active scanning.

The MLSDE-LESD.request primitive may include the NumBRB, ServiceID, and AvailableChannelID parameters.

The NumBRB parameter indicates the number of times the BRB is repeated.

The ServiceID parameter indicates the PAC service ID that the terminal desires to find.

The AvailableChannelID parameter indicates the channel number used for the service search.

The MLSDE-LESD.request primitive is generated from the upper layer and passed to the MLSDE, which causes the MLSDE to initiate an active LESD scan.

When the MLSDE receives the MLSDE-LESD.request primitive from the upper layer, it updates the macServiceID and macAvailableChannelID with the ServiceID parameter and the AvailableChannelID parameter value of the MLSDE-LESD.request primitive. In addition, the MLSDE generates a LESD request command and broadcasts the frame using the CSMA-CA algorithm. The MLSDE then increments the macMaxLESDRequestRetries value and sets a timer for macLESDResponseWaitTime to wait for receipt of the LESD response command.

MLSDE-LESD.indication primitive

FIG. 12A shows the structure of the MLSDE-LESD.indication primitive, and FIG. 12B shows the parameters of the MLSDE-LESD.indication primitive.

The MLSDE-LESD.indication primitive is used to inform the upper layer of the receipt of the LESD request command.

The MLSDE-LESD.indication primitive may include a ServiceID, an AvailableChannelID parameter.

The ServiceID parameter indicates the number of times the BRB is repeated.

The AvailableChannelID parameter indicates the channel number used for the service search.

Upon receiving the LESD request command, the LESDE checks the Service ID field value of the received LESD request command frame. The LESDE generates the MLSDE-LESD.indication primitive and notifies the upper layer of the reception of the LESD request command frame if the value of the Service ID field matches the value of the macServiceID of the terminal. If the Service ID field value does not match the macServiceID value, the MLSDE ignores the received LESD request command frame.

When the upper layer receives the MLSDE-LESD.indication primitive, it instructs the MLSDE to generate a LESD response command via the MLSDE-LESD.response primitive.

MLSDE-LESD.response primitive

Figure 13A shows the structure of the MLSDE-LESD.response primitive, and Figure 13B shows the parameters of the MLSDE-LESD.response primitive.

The MLSDE-LESD.response primitive is used by an upper layer to respond to the MLSDE-LESD.indication primitive provided from the terminal.

The MLSDE-LESD.response primitive may include the PANID, ServiceID, and CommunicationChannelID parameters.

The PANID parameter indicates the PAN identifier used in the UE.

The ServiceID parameter indicates a service ID used in the PAC wireless PAN to which the terminal is connected.

The CommunicationChannelID parameter indicates the channel number used for the service in the PAC wireless PAN to which the terminal is connected.

The MLSDE-LESD.response primitive is passed to the MLSDE by the higher layer.

When the MLSDE receives the MLSDE-LESD.response primitive, it updates the macCommunicationChannelID value with the CommunicationChannelID parameter value. After that, the MLSDE generates a LESD response command frame and broadcasts it to peripheral terminals.

MLSDE-LESD.confirm primitive

FIG. 14A shows the structure of the MLSDE-LESD.confirm primitive, and FIG. 14B shows the parameters of the MLSDE-LESD.confirm primitive.

The MLSDE-LESD.confirm primitive is used by MLSDE to report the result of a LESD request to an upper layer.

The MLSDE-LESD.confirm primitive contains the PANId, ServiceID, CommunicationChannelID, and Status parameters.

The PANId parameter indicates the PAN identifier used in the UE.

The ServiceID parameter indicates the Service ID used in the PAC wireless PAN.

The CommunicationChannelID parameter indicates the channel number used for the service in the PAC wireless PAN.

The Status parameter indicates the LESD resquest result.

When the MLSDE receives the LESD response command frame from the MLSDE of another terminal, it checks the Service ID field value of the received command frame. If the value of the Service ID field matches the value of the MACServiceID of the terminal, the MLSDE updates the MACCommunicationChannelID value with the Communication Channel ID value of the received command frame, sets the Status parameter value of the MLSDE-LESD.confirm primitive to SUCCESS, To the LESD request result.

After that, the MLSDE generates a LESD notification command frame and broadcasts it to peripheral terminals.

If the value of the Service ID field of the received command frame does not match the value of the macServiceID , the MLSDE ignores the received command frame.

Also, MLSDE After transmitting the LESD request command frame, it does not receive the LESD response command frame with a Service ID field that matches the macServiceID for up macLESDResponseWaitTime, by setting the value of the Status parameter MLSDE-LESD.confirm primitive to the upper TRANSACTION_EXPIRED Report to layer. Otherwise, the MLSDE sets the value of the Status parameter to INVALID_PARAMETER and reports it to the upper layer.

MLSDE-LESD-NOTIFY.indication primitive

FIG. 15A shows the structure of the MLSDE-LESD-NOTIFY.indication primitive, and FIG. 15B shows the parameters of the MLSDE-LESD-NOTIFY.indication primitive.

The MLSDE-LESD-NOTIFY.indication primitive is used by MLSDE to inform the higher layer that a LESD notification command frame has been received.

The MLSDE-LESD-NOTIFY.indication primitive contains the PANId, ServiceID, and CommunicationChannelID parameters.

The PANId parameter indicates the PAN identifier used in the UE.

The ServiceID parameter indicates the Service ID used in the PAC wireless PAN.

The CommunicationChannelID parameter indicates the channel number used for the service in the PAC wireless PAN.

The MLSDE-LESD-NOTIFY.indication primitive is used by MLSDE to inform the upper layer that a LESD notification command frame with a Service ID field value equal to the MACServiceID of the terminal has been received.

The MLSDE ignores the received command frame if the Service ID field value of the received LESD notification command frame does not match macServiceID .

The higher layer is informed of the receipt of the LESD notification command through receipt of the MLSDE-LESD-NOTIFY.indication primitive. The upper layer can know the service of the neighboring terminal and the physical channel used for the corresponding service through the MLSDE-LESD-NOTIFY.indication primitive. If the terminal is preparing to transmit a LESD request for the same service, the terminal may not transmit the LESD request through reception of the MLSDE-LESD-NOTIFY.indication primitive.

MLSDE-LESD-CS.request primitive

FIG. 16A shows the structure of the MLSDE-LESD-CS.request primitive, and FIG. 16B shows the parameters of the MLSDE-LESD-CS.request primitive.

The MLSDE-LESD-CS.request primitive is used to cause the MLSDE to initiate a channel sample (CS) procedure.

The MLSDE-LESD-CS.request primitive includes PANId, NumBRB, CSDuration, ServiceID, and CommunicationChannelID parameters.

The PANId parameter indicates the PAN identifier used in the UE.

The NumBRB parameter indicates the number of BRB iterations. As shown in FIG. 5, the time interval Num _BRB (T _BRB + T _LIFS ) represents one period in which the UE awakes for T _BRB to listen to the channel and _sleeps again for T _LIFS to perform channel sampling.

The CSDuration parameter indicates the time interval during which the UE listens to the channel specified by macLESDChannelID .

The ServiceID parameter indicates the Service ID used for the PAC service.

The CommunicationChannelID parameter indicates the channel number used for PAC service communication.

The MLSDE-LESD-CS.request primitive is generated by the upper layer when the service discovery of the UE has been successfully completed, or when the UE fails to perform the service discovery through the execution of the passive and active scan processes.

If the terminal fails to search for the service through the execution of the manual and active scanning processes, it is considered that the corresponding service does not exist in the vicinity, and the corresponding service is newly started by the terminal that has performed the scanning and the terminal enters the CS process .

When the MLSDE receives the MLSDE-LESD-CS.request primitive, it updates the relevant MAC PIB attribute value. That is, the value of macLESDdone is set to TRUE, and the values of macPANID , macNumBRB , macCSDuration , macServiceID , and macCommunicationChannelID are updated with the values of the PANID, NumBRB, CSDuartion, ServiceID, and CommunicationChannelID parameters of the MLSDE-LESD-CS.request primitive, respectively.

MLSDE-LESD-CS.confirm primitive

FIG. 17A shows the structure of the MLSDE-LESD-CS.confirm primitive, and FIG. 17B shows the parameters of the MLSDE-LESD-CS.confirm primitive.

The MLSDE-LESD-CS.confirm primitive is used by the MLSDE to report the results of the MLSDE-LESD-CS request to the upper layer.

The MLSDE-LESD-CS.confirm primitive may contain a Status parameter.

The Status parameter can have SUCCESS, FAILURE, and INVALID_PARAMETER values depending on the result of the LESD CS request.

When MLSDE successfully updates the MAC PIB attribute value corresponding to the parameter of the MLSDE-LESD-CS.request primitive, MLSDE sets the Status parameter value to SUCCESS and sends the result to the upper layer through the MLSDE-LESD-CS.confirm primitive report.

If the MLSDE receives an MLSDE-LESD-CS.request primitive during another LESD MAC operation, the MLSDE does not initiate the CS process and sets the Status parameter value to FAILURE to send the result to the upper layer via the MLSDE-LESD-CS.confirm primitive . Otherwise, the MLSDE sets the Status parameter value to INVALID_PARAMETER and reports the result to the upper layer via the MLSDE-LESD-CS.confirm primitive.

Hereinafter, a method of transmitting command frames by the terminal will be described.

Back-off method for CSMA-CA

The terminal can access the channel through the CSMA-CA algorithm when it wants to transmit each command frame.

The CSMA-CA algorithm and the parallel CSMA-CA algorithm can be selectively used as the channel access method of the UE, considering the expected discovery delay time and the power consumption of the UE.

Frame transmission method using serial CSMA-CA

18 is a flow chart illustrating a serial CSMA-CA procedure for low power service discovery (LESD).

18, the MS updates the backoff exponent (BE) value with macBE , which is a MAC PIB attribute value, and selects one integer value from 0 to 2 ^BE-1 values with an equal probability A backoff count (BC) value is set (S1801).

Thereafter, the MS converts the wireless operation mode into a reception mode and performs a CCA (Clear Channel Assessment) process (S1802). The terminal obtains a channel sample for a predetermined bit symbol interval (for example, an 8-bit symbol interval) in the CCA process, obtains an average value of the acquired channel samples, compares the average value with a preset threshold value (CCAThreshod) (busy or idle).

If the channel average value is greater than the threshold value, the terminal determines that the channel is in the busy state. Otherwise, the terminal determines that the channel is in the idle state (S1803).

If it is determined that the channel is busy, the UE performs the verification process BRB for a time up to _{(2 × T BRB -T CCA)} (S1804). Here, T _BRB represents the time taken to transmit one BRB, and T _CCA is a time for performing the CCA, which may be, for example, a time corresponding to an 8-bit symbol.

The wireless operation mode is set to the reception mode during the time when the terminal performs the BRB confirmation, and the terminal determines whether the BRB has been received (S1805). When the BRB is received, the terminal performs the BRB process (S1806). Or if the BRB is not received during the time, the UE performs the CSMA-CA procedure again from step S1801.

Alternatively, if it is determined in step S1803 that the channel status is idle, the UE turns off the receiver and determines whether the BC value is 0 (S1807).

In step S1807, if the BC value is not 0, the terminal decrements the BC value by 1, waits for a unit backoff time (UnitBackoff) (S1808), and then executes step S1807 again to determine whether the BC value is 0 Repeat the verification process. Here, the unit backoff time means a time that the terminal waits every time the BC value is decreased.

If the BC value becomes 0 through the BC reduction process, the UE sets the wireless operation mode to the reception mode and executes the CCA process (S1809).

If the channel status is idle, the mobile station switches the wireless operation mode to the transmission mode and then transmits a waiting frame (for example, a LESD request, a LESD response, and a LESD notification command frame) (S1811).

Alternatively, when the channel state in step S1810 as a result of confirming the result of the CCA busy terminal performs a verification process BRB for a time up to _{(2 × T BRB -T CCA)} (S1812). The wireless operation mode is set to the reception mode while the terminal confirms the BRB.

The terminal confirms whether the BRB has been received for the time period (S1813), and upon receipt of the BRB, the terminal performs a BRB process (S1814). Alternatively, if the BRB is not received during the time, the UE performs the CSMA-CA procedure again from step S1801.

Hereinafter, the BRB checking process performed in steps S1804 and S1812 of FIG. 18 will be described in more detail.

When the BRB checking process is started, the terminal operates in the receiving mode. In the BRB check process, the UE performs a process of detecting a preamble through a channel for a maximum (2 × T _BRB- T _CCA ) time. If a preamble is detected during this time, the UE performs frame synchronization through the detected preamble and receives the remaining SDF and PHR of the BRB. Once the PHR has been received, the terminal determines that the BRB has been received, and notifies the physical layer of the BRB reception to the MAC layer.

Hereinafter, the BRB process performed in steps S1806 and S1814 of FIG. 18 will be described in more detail.

If it is confirmed that the BRB has been received through the BRB checking process, the UE performs a subsequent process for the receiving BRB.

The physical layer (PHY) of the UE performs time synchronization with respect to the received frame through preamble reception and distinguishes the type of the received frame through the first 8-bit symbol of the SFD. Then, the physical layer (PHY) of the UE performs processing for the received frame according to the type of the transmission frame and the type of the received frame waiting in the queue as follows.

When the received frame type is the LESD request command

If the type of the received frame is a LESD request command frame, the first 2-bit symbol value of the PHR is checked and checked to be 0b11. After a 6-bit value of the value is 0b11 Ann Wu, PHR (BRBcount) is exhibits the number of the BRB be after repeating the received BRB, the UE is (BRBcount-2) the current time period after which BRB is repeated × (T _BRB + T _LIFS ). At this time, the BC that is currently operating also stores the current BC value, stops the operation of the timer, and waits. (BRBcount-2) x (T _BRB + T _LIFS ) After the lapse of the time, the UE activates the receiver to switch the wireless operation mode to the reception mode, receives the last BRB and confirms the last 6-bit symbol value of the PHR . This value indicates the length of the PHY Service Data Unit (PSDU) to be received after the T _LIFS time has elapsed at the completion of the BRB repetition. The terminal resumes the operation of the BC timer after this time has elapsed, and returns to the BC reduction process.

When the received frame type is the LESD response command

If the type of the received frame is the LESD response command frame, the physical layer (PHY) of the terminal receives the remaining PSDUs after the received BRB and informs the MAC via the primitive. The MAC checks the ServiceID of the received LESD response command and compares the ServiceID value with its macServiceID value. If the ServiceID value matches the macServiceID value, the MAC updates its macCommunicationChannelID value with the Communication Channel ID value of the received frame. After that, the MAC removes the command frame waiting in the transmission queue, stops the CSMA-CA in progress, and informs the upper layer that the LESD response command has been received using the MLSDE-LESD.confirm primitive.

Alternatively, the MAC declares that the processing of the received BRB is completed when the ServiceID and its own macServiceID value do not match each other. Thereafter, the MAC resumes the operation of the BC timer and returns to the BC reduction process.

When the received frame type is the LESD notification command

If the received frame type is the LESD notification command frame, the PHY receives the remaining PSDUs after the received BRB and informs the MAC via the primitive.

The MAC checks the ServiceID of the received LESD notification command and compares it with its macServiceID value. If the two values match, it updates its macCommunicationChannelID value with the Communication Channel ID value of the received frame.

After that, the MAC removes the command frame waiting in the transmission queue, stops the CSMA-CA in progress, and informs the upper layer that the LESD notification command has been received using the MLSDE-LESD-NOTIFY.indication primitive.

Alternatively, the MAC declares that the processing of the received BRB is completed when the ServiceID and its own macServiceID value do not match each other. Thereafter, the MAC resumes the operation of the BC timer and returns to the BC reduction process.

Frame transmission method using parallel CSMA-CA

19 is a flow chart illustrating a parallel CSMA-CA procedure for low power service discovery. 20 is a flowchart illustrating a backoff counting procedure performed in the parallel CSMA-CA process shown in FIG.

When Figure 19 and Figure 20, the first user terminal MAC PIB attribute back-off factor to the (attribute) value macBE (BE: Backoff Exponent) updates the value, and 0 to 2 ^BE-1 value of an integer value to equal probability And sets a backoff count (BC) value (S1901).

Then, the terminal starts a backoff counting procedure as shown in FIG. 20 (S1902). In the backoff count procedure, the UE sets a timer expired after the unit backoff time (UnitBackoff) and checks the BC value every time this timer is released (S1903). If the BC value is not 0, the terminal decreases the BC value by one, sets EndOfBackoff to FALSE, waits for the unit backoff time (S1904), and then checks the BC value again. Alternatively, if the BC value is 0, the terminal sets EndOfBackoff to TRUE (S1905) and exits the backoff count procedure.

Meanwhile, the UE switches the wireless operation mode to the reception mode separately from the backoff count procedure as described above, and simultaneously performs the CCA process (S1906). In the CCA process, the UE receives a channel for a preset time (e.g., 8-bit symbol time), compares the average value of the received channel with a threshold value, and determines a busy or idle state of the channel (S1907) . Here, if the channel average value is greater than the threshold value, the terminal determines that the channel is in the busy state. Otherwise, the terminal determines that the channel is in the idle state.

If it is determined that the channel is busy, the UE performs a BRB check process for a maximum time (2 × T _BRB -T _CCA ) (S 1908). The terminal confirms receipt of the BRB (S1909), and performs BRB processing when the BRB is received (S1910). The process of BRB processing is as described above. Or if the BRB is not received during the time, the UE performs the CSMA-CA procedure again from step S1901.

Alternatively, if it is determined in step S1907 that the channel status is idle, the UE determines whether the EndOfBackoff value is TRUE (S1911).

If the EndOfBackoff value is not TRUE in step S1911, the terminal turns off the receiver (T _BRB- T _CCA ) and waits for a time (S1912), and resumes the CCA process.

Alternatively, if the EndOfBackoff value is TRUE in step S1911, the terminal sets the wireless operation mode to the reception mode and executes the CCA procedure (S1913).

If the channel status is idle, the mobile station switches the wireless operation mode to the transmission mode and transmits a waiting frame to the channel (S1915).

Or, if the channel conditions as a result of confirming the channel state in step S1914 is busy terminal performs a verification process BRB for a time up to _{(2 × T BRB -T CCA)} (S1916). The wireless operation mode is set to the reception mode while the terminal confirms the BRB.

The terminal checks whether the BRB has been received for the time period (S1917). When the terminal receives the BRB, it performs a BRB process (S1918). Alternatively, if the BRB is not received during the time, the terminal performs the CSMA-CA procedure again from step S1901.

Hereinafter, the physical layer technology for LESD will be described.

21 shows a structure of a physical layer frame.

The physical layer frame may be mainly composed of a synchronization header (SHR), a physical layer header (PHR) header, and a physical service data unit (PSDU). Here, SHR and PHR correspond to BRB.

The preamble may be configured such that a specific bit string (for example, "01010101") is repeated.

SFD is used to indicate the start of a frame, and can have different values depending on the type of frame.

22 shows an example of the SFD used in the LESD.

As shown in FIG. 22, the terminal can determine the type of the frame based on the SFD, and the SFD can have different values according to the Request, Response, Notification, and No PDSU frames. Here, No PSDU is used for BRB as a frame without PSDU.

Therefore, when the terminal uses the eavesdropping technique, the terminal can selectively receive only the required type of frame. No PSDUs are used for BRB as PSDU-free frames.

23A and 23B show physical layer headers.

The physical layer header PHR may be composed of one octet and the first bit T ₀ indicates the type of frame and the remaining bits L ₆ -L ₀ may indicate the length of the frame or the BRB count .

If the type of the frame is either Request, Response, or Notification, the PHR can indicate the length of the frame. If the type of the frame is No PDSU, the remaining bits indicate the number of remaining BRB repetitions, i.e., a BRB count .

For example, if the bit indicating the frame type is '0', the frame type is the LESD PSDU and the remaining 7 bits of the PHR indicate the frame length. Or if the bit indicating the frame type is '1', it indicates that there is no PSDU and the remaining 7 bits of the PHR indicate the BRB count.

In the case of No PDSU, the UE can receive the BRB according to the number of times of repeating the remaining BRBs by confirming the BRB count, and accordingly, it is unnecessary to receive the BRB unnecessarily until the preset final time.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

110: Manual LESD scan 120: Active LESD scan
130: channel sampling 140: PAN joining
150: PAN start 210: NHL
220: MLSDE 310: NHL
320: MLSDE 330: MLSDE
340: NHL 410: NHL
420: MLSDE

Claims (20)

According to a service discovery method performed in a terminal,
Performing a passive scan for searching for a specific service based on whether a frame including a specific service identifier is received in the MAC layer of the terminal; And
And performing an active scan to broadcast a service discovery request frame for searching for the specific service if the MAC layer fails to search for the specific service. In claim 1,
The step of performing the passive scan may include:
The MAC layer receiving a scan request primitive including a service identifier and a channel identifier from an upper layer;
Updating the service identifier and the channel identifier of the MAC layer based on the service identifier and the channel identifier;
Comparing the service identifier included in the service discovery response command frame or the service discovery notification command frame with the service identifier of the MAC layer when the service discovery response command frame or the service discovery notification command frame is received from the physical layer ; And
If the service identifier included in the service discovery response command frame or the service discovery notification command frame matches the service identifier of the MAC layer, the MAC layer determines that the service discovery response command frame or the service discovery notification command frame has been received And notifying the layer of the service discovery. In claim 1,
Wherein the MAC layer performs the passive scan for a time determined based on the reception time of one basic repeating block (BRB) and the number of basic repeating blocks. In claim 1,
The step of performing the passive scan may include:
Wherein the MAC layer passes the manual scan result to the upper layer via a scan acknowledgment primitive. In claim 1,
The service discovery method includes:
If the search for the specific service is successful by performing the manual scan,
Connecting the terminal to a personal area network (PAN) providing the specific service; And
Further comprising performing channel sampling (CS) while the terminal attempts to access the personal communication network. In claim 1,
Wherein performing the active scan comprises:
Receiving, by the MAC layer, a service discovery request primitive indicating an active scan from an upper layer;
Broadcasting the service discovery request command frame after the MAC layer generates a service discovery request command frame corresponding to the received service discovery request primitive;
Confirming whether a service identifier included in the service discovery response frame matches a service identifier of the MAC layer when the MAC layer receives a service discovery response command frame from another terminal during a predetermined response waiting time;
And transmitting, to the upper layer, a service discovery confirmation primitive indicating that the MAC layer has received the service discovery response frame if the service identifier included in the service discovery response frame matches the service identifier of the MAC layer Discovery method. In claim 6,
Wherein the transmitting the service discovery acknowledgment primitive to an upper layer comprises:
Wherein the MAC layer generates a service discovery notification command frame and broadcasts the service discovery notification command frame. In claim 6,
Wherein performing the active scan comprises:
And if the service identifier included in the service discovery response frame matches the service identifier of the MAC layer, the service discovery request command frame waiting for transmission is not transmitted for service discovery. In claim 6,
The service discovery method includes:
If the service discovery response command frame is not received from another terminal during the response waiting time, repeating the service discovery request command frame until the preset maximum retransmission number is not exceeded; And
And transmitting a primitive indicating that active scanning has failed to an upper layer if the service discovery response command frame is not received until the preset maximum retransmission number is exceeded. In claim 1,
The service discovery method includes:
If the search of the specific service is failed as a result of performing the active scan, activating the receiver of the terminal only in a channel sampling period included in the channel sampling period for each predetermined channel sampling period, and monitoring reception of the service discovery request command frame And performing channel sampling on the received service discovery. In claim 10,
Wherein performing the channel sampling comprises:
Receiving, by the MAC layer, a channel sampling request primitive instructing to perform channel sampling from the upper layer;
Updating the number of basic repetition blocks (BRBs) and a channel sampling interval of the MAC layer to a basic repetition block count and a channel sampling interval value included in the channel sampling request primitive; And
Wherein the MAC layer monitors reception of the service discovery request command frame in the channel sampling interval. In claim 11,
Wherein performing the channel sampling comprises:
Wherein if the service discovery request command frame is not received during the channel sampling interval, the MAC layer deactivates the receiver of the terminal and waits until the next channel sampling period. In claim 11,
Wherein performing the channel sampling comprises:
Comparing the service identifier included in the received service discovery request command frame and the service identifier of the MAC layer when the service discovery request command frame is received during the channel sampling interval; And
If the service identifier included in the received service discovery request command frame matches the service identifier of the MAC layer, transmitting a service discovery indication primitive indicating reception of a service discovery request command frame to an upper layer Lt; RTI ID = 0.0 > discovery < / RTI > In claim 13,
Wherein performing the channel sampling comprises:
Receiving, by the MAC layer, a service discovery response primitive from the upper layer in response to the service discovery indication primitive transmitted from the upper layer;
Wherein the MAC layer generates a service discovery response command frame and broadcasts the generated service discovery response command frame. According to a service discovery method performed in a terminal,
Receiving a service discovery request command frame from another terminal;
When the service identifier included in the received service discovery request command frame is the same as the service identifier of the MAC layer of the terminal, transmits a service discovery indication primitive indicating reception of the service discovery request command frame to the MAC layer ;
The MAC layer receiving a service discovery response primitive from the upper layer; And
The MAC layer generates a service discovery response command frame and broadcasting the generated service discovery response command frame. In claim 15,
The service discovery method includes:
Receiving a service discovery notification command frame from another terminal after broadcasting the service discovery response command frame; And
If the service identifier included in the service discovery notification command frame is the same as the service identifier of the MAC layer, transmitting, by the MAC layer, a notification indication primitive instructing reception of a service discovery notification command frame to an upper layer Lt; RTI ID = 0.0 > discovery < / RTI > According to a service discovery method performed in a terminal,
Performing a passive scan for searching for a specific service based on whether a frame including a specific service identifier is received in the MAC layer of the terminal; And
If the search for the specific service is successful, the MAC layer activates the receiver of the terminal only in a channel sampling period included in the channel sampling period according to a predetermined channel sampling period, and performs channel sampling for monitoring reception of a service discovery request command frame Wherein the service discovery method comprises the steps of: In a discovery method performed in a terminal,
Setting a backoff count value;
Performing a clear channel assessment (CCA);
Confirming receipt of a basic repetition block (BRB) for a first time when the channel status is busy; And
When the basic repetition block is received for the first time, classifies the type of the received frame based on the information included in the basic repetition block, and performs processing of the basic repetition block corresponding to the type of the received frame A method of service discovery comprising: In claim 18,
Wherein performing the processing of the basic repetition block comprises:
Determining a type of a received frame based on a SFD (Start Frame Delimiter) of the basic repetition block,
If the received frame is a service discovery request frame, the terminal deactivates the receiver for a specific period of time based on the number of basic repetition blocks indicated by the header of the received frame, And decrementing the backoff count value by activating,
If the received frame is a service discovery response frame, if the service identifier included in the received service discovery response frame is the same as the service identifier of the MAC layer of the terminal,
If the received frame is a service discovery notification frame, if the service identifier included in the received service discovery notification frame is the same as the service identifier of the MAC layer of the terminal, the communication channel identifier of the MAC layer is transmitted to the received service discovery notification frame To the communication channel identifier included in the frame, and removes frames waiting for transmission. In claim 18,
The service discovery method includes:
Independently of performing the channel state check,
A back-off count value is decremented until the set back-off count value has a predetermined value, and a standby state is set in a state in which the receiver of the terminal is deactivated by a preset unit back- And performing an off-count procedure for the service discovery.

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