KR20090062696A - System and method for checking connection in a communication system - Google Patents

Abstract

A system for confirming a connection in a communication system and a method therefor are provided to control a base station from a remote place by using a local control station equipped outside the base station. A controllerperiodically forms a state report message. A wireless local area data communications unit transmits the state report message, and receives a power reset signal from the outside. A power resetting unit resets the power in response to the power reset signal. A remote power control station forms the power reset signal for resetting the power of the base station(110) which is determined that it is in an abnormal state, and then outputs the power reset signal to the base station.

Description

SYSTEM AND METHOD FOR CHECKING CONNECTION IN A COMMUNICATION SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system, and more particularly to a mobile station (MS) and a base station in a broadband wireless access (BWA) communication system. (BS: Base Station, hereinafter referred to as "BS") relates to a system and method for checking the connection (connection) state.

In the next generation communication system, active researches are being conducted to provide users with services of various quality of service (QoS: QoS) having high transmission speeds. In particular, in the current generation communication system, a wireless local area network (WLAN) system and a wireless metropolitan area network (WMAN) will be referred to as "WMAN". Researches are being actively conducted to support high-speed services in the form of guaranteeing mobility and QoS to BWA communication systems such as systems, and the representative communication systems are IEEE (Institute of Electrical and Electronics Engineers) 802.16a / d communication system and IEEE 802.16e communication system.

The IEEE 802.16a / d communication system and the IEEE 802.16e communication system, which are the BWA communication system, orthogonal frequency division (OFDM) to support a broadband transmission network on a physical channel of the WMAN system. A multiplexing (hereinafter referred to as "OFDM") / orthogonal frequency division multiple access (OFDMA) scheme is a communication system employing the scheme. The IEEE 802.16a / d communication system currently considers only a single cell structure and a state in which a subscriber station (SS) (hereinafter referred to as SS) is fixed, i.e., does not consider SS mobility at all. System. In contrast, the IEEE 802.16e communication system is a system considering the mobility of the SS in the IEEE 802.16a communication system, and the SS having the mobility is referred to as an MS.

In consideration of the mobility of the MS in the IEEE 802.16e communication system, the power consumption of the MS acts as an important factor of the entire system. Accordingly, the sleep mode operation between the MS and the BS is minimized to minimize the power consumption of the MS. And an active mode operation corresponding to the sleep mode operation has been proposed, and a method of checking a connection state between the BS and the MS in the sleep mode and the active mode is required.

In this way, the BS and the MS check the connection state. In the sleep mode, the BS and the MS periodically perform ranging to confirm the access state or UL (UpLink) data acknowledgment (UL). Although there is a method of checking a connection state by using a data grant message, that is, a keep-alive check in sleep mode, a method of checking a connection state between the BS and the MS in an active mode may be used. There is no way to confirm the access state when the uplink data is not received for more than a predetermined time only through the uplink data reception from the.

More specifically, the operation of the sleep mode is an operation in which there is no data transmission and reception between the BS and the MS, and checks the connection state between the BS and the MS to minimize power consumption of the MS or to the MS. Delete the information. In other words, as a result of checking the connection state, if the connection between the BS and the MS is maintained in the sleep mode, the sleep interval of the MS is increased to reduce power consumption of the MS or the connection between the BS and the MS is lost. In this case, information about the MS stored in the BS may be deleted, for example, a connection identifier (CID: Connection Identifier, hereinafter referred to as “CID”) assigned to the MS may be deleted to prevent memory waste of the CID and the BS. .

Accordingly, a periodic ranging request code / ranging response (RNG-RSP: Ranging Response (RNG-RSP)) message between the BS and the MS is performed through periodic ranging. Confirms the access state in the sleep mode through transmission and reception of the BS, or the BS transmits an uplink data grant message to the MS and confirms the access state in the sleep mode by receiving an uplink resource allocation request message from the MS. In this case, the MS transmits an uplink resource allocation request message set to '0' to the BS when its uplink resource allocation is unnecessary, or an uplink resource allocation request including allocation request information when uplink resource allocation is required. By transmitting a message to the BS and confirming whether the uplink resource allocation request message is received, the BS checks the connection state with the MS.

Meanwhile, the active mode operation is an operation of transmitting and receiving data between the BS and the MS. As the data is transmitted and received while the connection between the BS and the MS is maintained, the active mode operation confirms a connection state between the BS and the MS by transmitting and receiving data. . However, when there is no data transmission and reception between the BS and the MS for a predetermined time or more in the active mode, in particular, the BS transmits data to the MS but fails to receive data from the MS for a time longer than a data reception interval. There is no way to check the connection status of the MS.

As the connection state between the BS and the MS is not confirmed in the active mode, if the operation corresponding to the connection state between the BS and the MS, that is, the connection between the BS and the MS is maintained, the BS informs the MS. Perform normal operations for the MS, for example, perform resource allocation, transmit power control, modulation and coding scheme (MCS: Modulation and Coding Scheme) operation of the MS, and the like If the connection between the BS and the MS is disconnected, there is a problem in that the information on the MS cannot be deleted as described in the sleep mode. In particular, when the BS cannot check the connection state between itself and the MS, and determines that the disconnected state is maintained as the connection with the MS, the BS allocates the CID and the memory of the BS to the MS. If it is determined that the maintained state is disconnected from the MS, there is a problem in that the reliability of communication is lowered by disconnecting from the MS.

Accordingly, an object of the present invention is to provide a system and method for confirming a connection state between a base station and a mobile station by checking whether a predetermined message is received from the mobile station in a communication system.

Another object of the present invention is to provide a system and method for confirming a connection state between a base station and a mobile station by checking whether a predetermined message is received by the mobile station in an active mode in a communication system.

In addition, another object of the present invention is to check the connection state between the base station and the mobile station by checking whether or not to receive a predetermined message from the mobile station when data transmission and reception between the base station and the mobile station in the active mode of the communication system does not exist for a predetermined time or more. To provide a system and method.

A method of the present invention for achieving the above objects comprises a method of confirming a connection with a mobile station by a base station of a communication system comprising a base station and a mobile station provided with the service. At least one of a bandwidth allocation request message, an uplink transmission power report message, and an uplink transmission power control request message from the mobile station, if the data is not received for a predetermined time or more; And receiving the at least one message and confirming that the connection with the mobile station is maintained.

Another method of the present invention for achieving the above objects is a method of confirming a connection with a mobile station by a base station of a communication system including a base station and a mobile station provided with the service, operating in an active mode. Confirming whether or not to receive data from the mobile station; if receiving data from the mobile station for a predetermined time or more, confirming whether or not to receive a report response message from the mobile station; And receiving the report response message or the channel quality information, and confirming that the connection with the mobile station is maintained.

Another method of the present invention for achieving the above object is a method of confirming a connection with a mobile station by a base station of a communication system including a base station and a mobile station serviced by the base station. Checking whether data is received from the mobile station, and if data is not received from the mobile station for a predetermined time or more, according to whether or not a response message to an uplink data approval message or a channel quality information message indicating channel quality is received. Confirming the maintenance of the connection with the mobile station.

A system for confirming connection of the present invention for achieving the above objects includes a base station and a mobile station provided with a service from the base station and operating in an active mode, wherein the base station confirms whether data is received from the mobile station. If the data is not received for a predetermined time or more, the mobile station determines whether the mobile station has received at least one of a bandwidth allocation request message, an uplink transmission power report message, and an uplink transmission power control request message. Receiving at least one message confirms that the connection with the mobile station is maintained.

Another system for verifying the connection of the present invention for achieving the above objects comprises a base station and a mobile station provided with service from the base station and operating in an active mode, the base station whether or not to receive data from the mobile station. If the mobile station does not receive data from the mobile station for more than a predetermined time, it is determined whether a report response message is received from the mobile station, or whether channel quality information is received through a feedback channel from the mobile station. Or upon receiving the channel quality information, confirms that the connection with the mobile station is maintained.

Another system for verifying connection of the present invention for achieving the above objects comprises a base station and a mobile station serviced from the base station and operating in an active mode, the base station whether or not to receive data from the mobile station. If it is not received for more than a predetermined time from the mobile station, and confirms whether to receive a response message to the uplink data acknowledgment message or a channel quality information message indicating the channel quality, and maintains the connection with the mobile station. .

The present invention provides a bandwidth allocation request message, an uplink transmission power report message, an uplink transmission power control request message, and a downlink received from the mobile station even if data is not received from the mobile station for a predetermined time or more in an active mode of the communication system. The connection status of the mobile station can be confirmed by checking whether the channel quality information report response message or the channel quality information through the dedicated channel assigned to the mobile station is received.

In addition, the present invention sleeps a mobile station even if it does not receive a bandwidth allocation request message, an uplink transmit power report message, an uplink transmit power control request message, a downlink channel quality information report response message, or channel quality information in an active mode. By switching to the mode, the bandwidth allocation request message corresponding to the uplink data acknowledgment message may be checked to check the access state of the mobile station.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to distract from the gist of the present invention.

The present invention is a communication system, for example, a system for confirming a connection state in an Institute of Electrical and Electronics Engineers (IEEE) 802.16 communication system, which is a broadband wireless access (BWA) communication system. And a method. Here, in the embodiment of the present invention to be described later, orthogonal frequency division multiplexing (OFDM) / orthogonal frequency division multiple access (OFDM) in the IEEE 802.16 communication system for convenience of description. Although a communication system using the (OFDMA: Orthogonal Frequency Division Multiple Access, hereinafter referred to as 'OFDMA') method is described as an example, the access confirmation system and method proposed by the present invention can be applied to other communication systems.

In addition, the present invention is a base station (BS: Base Station, referred to as "BS") that manages a predetermined cell in a communication system and a mobile station (MS) existing in the predetermined cell and receiving a communication service from the BS (MS). A system and method for checking a connection state between a mobile station and a mobile station (hereinafter referred to as MS) are proposed. In the embodiment of the present invention to be described later, in the communication system to which the OFDM / OFDMA method is applied, the connection status between the BS and the MS operating in the sleep mode (sleep mode) and active mode (active mode), in particular, the BS and MS in the active mode We propose a system and method for checking the connection status between the devices.

In this case, in the active mode in which data is transmitted and received between the BS and the MS, when there is no transmission and reception of the data between the BS and the MS for a predetermined time or more, the BS transmits data to the MS, but the time is longer than the data reception interval. If no data is received from the MS during this time, the BS transmits an UL (UpLink) UL data grant message, for example, a unicast data grant message, to the MS. The MS checks whether the MS receives the uplink data corresponding to the uplink data acknowledgment message, that is, the unicast data.

In addition, according to the present invention, if the BS transmits data to the MS in the active mode as described above but fails to receive data from the MS for more than a data reception interval, the BS allocates data to the MS through a dedicated channel allocated to the MS. Receiving a control message from the MS, for example, a bandwidth allocation request (BW) message, an uplink Tx Power Report (UL) message, an uplink transmit power control request message, which is a resource allocation request Check the connection status with the MS by checking whether or not.

In addition, the present invention, if the data is not received from the MS for more than a data reception interval in the active mode, the channel quality information (CQI: Channel Quality Information) from the MS through the dedicated channel allocated to the MS by the BS Information, hereinafter referred to as 'CQI' message, for example, downlink CQI report request (REP-REQ: Report Request, hereinafter referred to as 'REP-REQ') / Report Response (REP-RSP: Report Response, hereinafter) A feedback channel, that is, a dedicated channel allocated to the MS to transmit a CQI to the BS, or a CQI channel (hereinafter referred to as a 'CQICH'). Check the connection status with the MS by checking whether or not the CQI is received through).

When the BS does not receive the above-mentioned messages and information from the MS, the present invention provides an Unsolicited MOB_SLP-RSP (Unsolicited MOB_SLP-RSP). Send a message to the MS to switch the operation mode with the MS to the sleep mode, and use the uplink data acknowledgment message used to confirm a connection state between the BS and the MS in the sleep mode. Check the connection status between MSs. In other words, if the acknowledgment message, the control message, and the CQI message and the CQI are not received as a result of confirming the connection state between the BS and the MS in the active mode, the Unsolicited MOB_SLP-RSP message is not received. Transmits the uplink data acknowledgment message transmitted by the BS to confirm the connection in the sleep mode, and transmits the uplink data acknowledgment message to the MS; In response to the check whether the UL bandwidth request (UL BW) request message from the MS to confirm the connection state with the MS. Here, the MS transmits an uplink bandwidth request message set to '0' to the BS when its uplink resource allocation is unnecessary, or an uplink bandwidth allocation message including resource allocation request information when uplink resource allocation is required. Is transmitted to the BS, and the BS checks the connection state with the MS by checking whether the uplink bandwidth request message is received.

At this time, the present invention, the bandwidth allocation request message, the uplink transmission power report message, the uplink transmission power control request message, the REP-REQ / REP-RSP message, the CQI received through the CQICH, or uplink from the MS Check the bandwidth request message to confirm the MS to check the connection status and the connection status with the MS.

As a result of confirming the connection state between the BS and the MS, if the connection between the BS and the MS is maintained, the BS operates in a normal mode for the MS in an active mode, for example, resource allocation, transmission power control, and modulation of the MS. And coding operation (MCS: Modulation and Coding Scheme, hereinafter referred to as 'MCS') level control, and accordingly, by supporting the data transmission and reception through a normal operation for data transmission and reception between the BS and the MS. Improves data transmission and reception efficiency, and determines whether the connection is maintained as disconnected from the MS by checking the state in which the connection with the MS is maintained even if no data is received from the MS for a predetermined time or more. Deletion of information about the connection, that is, disconnection with the MS, prevents a decrease in communication reliability.

In addition, if the connection between the BS and the MS is disconnected as a result of the checking, the information on the MS is deleted, for example, a connection identifier (CID) assigned to the MS in an initial access procedure for accessing the MS. And the like, thereby preventing memory waste of the CID and BS allocated to the MS. Here, when the connection is re-requested from the MS identified as disconnected, the initial connection procedure is performed again with the MS. Next, power control in the communication system according to the embodiment of the present invention will be described with reference to FIG. 1.

1 is a view schematically showing the structure of a communication system according to an embodiment of the present invention.

Referring to FIG. 1, the communication system includes a BS 110 managing a predetermined cell 100, an MS1 120 present in the cell 100 and receiving a communication service from the BS 110. MS2 130 is included. Here, the MSs, that is, MS1 (120), MS2 (130) has both mobility and fixed, for convenience of description MS1 (120), MS2 (130) operates in the active mode, the BS (110) ) And the transmission and reception between the MSs 120 and 130 will be described using the OFDM / OFDMA scheme.

As described above, the BS 110 checks whether the MSs 120 and 130 receive data from the MSs 120 and 130 in the active mode, and confirms connection states with the MSs 120 and 130, respectively. In this case, if data is not received from the MSs 120 and 130 for a predetermined time or more, the BS 110 receives an unicast data acknowledgment message that is an acknowledgment message including information indicating whether the MSs 120 and 130 transmit data. Check the reception state to check the connection state with the MS (120, 130). Alternatively, the BS 110 checks whether a bandwidth allocation request message, an uplink transmission power report message, and an uplink transmission power control request message, which are control messages from the MSs 120 and 130, are received. Check the connection state of the MSs or check the connection state of the MSs 120 and 130 by checking whether or not the REP-REQ / REP-RSP message, which is a CQI report message with the MSs 120 and 130, or the MSs ( The connection state with the MSs 120 and 130 is checked by checking whether the CQI is received through the CQICH from the 120 and 130.

In addition, the BS 110 confirms whether the MSs 120 and 130 have received the above-mentioned messages and information, for example, an acknowledgment message, a control message, a report message, and a CQI, to confirm the connection status with the MSs 120 and 130. If the messages and information are not received from the devices 120 and 130, an Unsolicited MOB_SLP-RSP message is transmitted to the MSs 120 and 130 in the active mode to switch the operation mode of the MSs 120 and 130 from the active mode to the sleep mode. In addition, the MS transmits an uplink data grant message to the MSs 120 and 130, which is used to confirm a connection state between the BS and the MS in the sleep mode. Then, the MS determines whether the MSs 120 and 130 receive the uplink bandwidth request message from the MSs 120 and 130 in response to the transmitted UL data acknowledgment message. As described above, the MSs 120 and 130 transmit the uplink bandwidth request message set to '0' when the uplink resource allocation is unnecessary because there is no data to transmit to the BS 110. Or uplink resource allocation is required because there is data to be transmitted to the BS 110, an uplink bandwidth request message including uplink resource allocation request information is transmitted to the BS 110. BS 110 confirms the reception state of the uplink bandwidth request message to confirm the connection state of the MS (120, 130).

In addition, the BS 110 receives a bandwidth allocation request message, an uplink transmission power report message, an uplink transmission power control request message, which are control messages from the MSs 120 and 130, and the REP-REQ / REP-RSP. Check MS1 (120) and MS2 (130) to check a connection state by checking whether a message is transmitted and received, whether CQI is received through the CQICH, and whether the UL bandwidth request message is received, and the MSs (120,130) Check the connection status.

The BS 110 confirming the connection state of the MSs 120 and 130 for each MS 120 and 130 acquired during the initial connection procedure with the MSs 120 and 130 corresponding to the connection state of the MSs 120 and 130. The information and the CIDs assigned to the MSs 120 and 130 are deleted or normal operations are performed on the MSs 120 and 130. Next, the operation of the BS in the communication system according to the embodiment of the present invention will be described in more detail with reference to FIG. 2.

2 is a diagram illustrating an operation process of a BS in a communication system according to an embodiment of the present invention.

Referring to FIG. 2, first, in step S210, the BS operates in an active mode with an MS, that is, performs data transmission / reception with the MS. Then, in step S220, the BS checks whether data is received from the MS during a predetermined time through a resource allocated to the MS, for example, during a data reception interval, that is, whether data is received from the MS in an active mode. Check the connection status with the MS. As a result of the check in step S220, if the data is not received from the MS, that is, if there is no data from the MS for more than the data reception period in the active mode, the connection with the MS is disconnected and proceeds to step S230, In step S230, the BS transmits an uplink data grant message to the MS in order to confirm the connection state with the MS.

Here, the BS schedules data transmission and reception with the MS and then transmits an uplink data grant message including MAP information to the MS so that the MS transmits uplink data, that is, unicast data, to the BS. At this time, the BS allocates resources for the MS to transmit unicast data, and transmits the uplink data grant message to transmit unicast data through the allocated resources. Then, the MS receives the uplink data acknowledgment message and transmits unicast data to the BS, and in step S240, the BS checks whether the unicast data is received from the MS and checks the connection state with the MS again. . At this time, if there is unicast data to be transmitted to the BS, the MS transmits the unicast data to the BS in response to the uplink data acknowledgment message, and there is no unicast data to be transmitted to the BS. Otherwise, transmits the padded data unit to the BS in response to the uplink data grant message. Then, the BS checks the connection state with the MS through the reception of the unicast data.

In this case, when the MS transmits a padded data unit because there is no unicast data to transmit to the BS, the padded data unit is referred to as a higher layer, that is, physical (hereinafter, referred to as 'PHY'). The BS cannot confirm receipt of the unicast data, i.e., the padded data unit, because it is not transmitted from the layer to the Medium Access Control (MAC) layer. Can be.

That is, in step S240, the BS may not correctly check whether the unicast data has been received, thereby incorrectly confirming a connection state with the MS. However, in the present invention, the BS may provide a bandwidth as a control message to be described in more detail below. Check the connection status of the MS by checking whether an allocation request message, an uplink transmit power report message, or an uplink transmit power control request message are received, or as a CQI message, a REP-REQ / REP-RSP message or a CQI through a CQICH. By confirming whether or not to check the connection status of the MS to check the connection status and the MS can accurately check the connection status.

As a result of the checking in step S240, if the unicast data is not received, it is determined that the connection with the MS has been disconnected. In step S250, the BS sends an Unsolicited MOB_SLP-RSP message to the MS as described above. Transmits an operation mode of the MS from an active mode to a sleep mode, and transmits an uplink data acknowledgment message to the MS to confirm a connection state between the BS and the MS in the sleep mode.

Next, in step S260, the BS checks whether the uplink band request message is received from the MS in response to the uplink data acknowledgment message transmitted in step S250 to confirm the connection state with the MS. Here, the uplink band request message transmitted by the MS is a message for requesting uplink resource allocation to the BS in response to the presence or absence of data to be transmitted to the BS by the MS. That is, if no uplink resource allocation is necessary because there is no data to transmit to the BS, the MS transmits an uplink bandwidth request message set to '0' to the BS. An uplink bandwidth allocation message including allocation request information is transmitted to the BS. In this case, when the MS does not need to allocate an uplink resource, unlike the transmission of the padded data unit, the MS transmits the uplink bandwidth request message set to '0' so that the BS accurately checks whether or not the message is received. Check the connection with the MS.

As a result of the check in step S260, if the MS does not receive an uplink bandwidth request message, it confirms that the connection with the MS has been disconnected, and proceeds to step S270. In step S270, the BS deletes the information on the disconnected MS. That is, the MS reinitialize error of the MS, thus deleting the information on the MS acquired during the initial connection with the MS, and thus wasting BS's own memory and CID allocated to the MS according to the storage of the information on the MS. prevent. At this time, if a connection request is received from the disconnected MS, an initial access procedure is performed with the MS.

On the other hand, as a result of the check in step S220, when receiving data from the MS, the BS is connected to the MS in the active mode is maintained, so proceeds to step S280, and in step S280 BS to the MS in the active mode Normal operation, for example, resource allocation for data transmission and reception with the MS, transmission power control, and MCS level control. When the unicast data is received from the MS, the BS proceeds to step S280 in which the connection with the MS is maintained in the active mode. In step S280, the BS proceeds to step S280. Perform a normal operation on the MS in the active mode. In addition, if it is determined in step S260 that an uplink bandwidth request message is received from the MS, that is, the connection with the MS is maintained, the BS maintains the connection with the MS in the active mode as described above. In step S280, the BS performs a normal operation on the MS in step S280.

Thus, even though the communication system according to the embodiment of the present invention cannot receive the data from the MS for a predetermined time or more in the active mode and cannot check the connection state through the reception of the data, the MS receives the unicast data transmitted by the MS. By checking whether the connection state with the MS is confirmed, the connection state with the MS is confirmed not only in the sleep mode but also in the active mode. In addition, even if the unicast data is not received when confirming the connection with the MS in the active mode, an Unsolicited MOB_SLP-RSP message is transmitted to the MS to switch the operation mode of the MS from the active mode to the sleep mode, and in the sleep mode. After transmitting the uplink data grant message, it is checked whether the uplink bandwidth request message is received in response to the uplink data grant message to confirm the connection state with the MS. This prevents wasting of the BS's memory and CIDs assigned to the MS according to the storage of information about the MS and improves the reliability of the communication. Next, the operation of the BS in the communication system according to another embodiment of the present invention will be described in more detail with reference to FIG. 3.

3 is a diagram illustrating an operation process of a BS in a communication system according to another embodiment of the present invention.

Referring to FIG. 3, first, in step S305, the BS operates in an active mode with an MS, that is, performs data transmission / reception with the MS. Next, in step S310, the BS transmits an uplink channel descriptor (UCD) message including a Tx Power Report (TLV) type length value (UCD) message to the MS. A registration request (REG-REQ: REG-REQ) / registration response (REG-RSP) or REG-RSP (hereinafter referred to as REG-RSP). The MAC header and extended subheader support is checked through the TLV of the message to confirm the MAC header and extended subheader support. Here, the Tx Power Report TLV is shown in Table 1 below, and the MAC header and extended subheader supporting TLVs are shown in Table 2 below.

Then, in step S315, the BS checks whether or not the data is received from the MS during a predetermined time through a resource allocated to the MS, for example, during a data reception period, that is, whether the data is received from the MS in an active mode. Check the connection status with the MS. As a result of the check in step S315, if the data is not received from the MS, that is, if there is no data from the MS for a time longer than the data reception interval in the active mode, it is determined that the connection with the MS is disconnected, and the process proceeds to step S320. In step S320, the BS transmits an uplink data grant message to the MS in order to confirm the connection state with the MS.

Next, in step S325, the BS checks whether a control message, for example, a bandwidth allocation request message, an uplink transmission power report message, or an uplink transmission power control request message, is received in response to the transmitted uplink data grant message. Check the connection status with the MS again. Here, the bandwidth allocation request message is a message for requesting the bandwidth allocation to the BS in order to send and receive data with the BS in the active mode, the uplink transmission power report message is the transmission power control scheme of the MS is open loop ( In the case of the open-loop power control scheme, the MS reports the information on the MS's own transmit power determined by the MS itself to the BS. The uplink transmit power control request message is a closed loop of the transmit power control scheme of the MS. -loop) In case of a power control scheme, this is a message for requesting transmission power control of the MS to the BS.

That is, the BS schedules data transmission and reception with the MS and informs the MS to request the resource allocation, report the uplink transmission power, or control the uplink transmission power through MAP information, and the MS informs the MS. After checking the MAP information, the bandwidth allocation request message, the uplink transmission power report message, and the uplink power control request message are transmitted to the BS through a channel allocated to the BS. In this case, the bandwidth allocation request message, the uplink transmission power report message, and the uplink power control request message include identification information of the MS that transmitted the messages. Then, the BS checks whether the bandwidth allocation request message, the uplink transmission power report message, and the uplink power control request message have been received, that is, the bandwidth request header and the uplink transmission power report header or the PHY channel report header or the uplink. Transmit Power Report Check the extended subheader to verify the connection with the MS.

As a result of the check in step S325, if the control message is not received, it is determined that the connection with the MS is disconnected, and the process proceeds to step S330. In step S330, the BS transmits an Unsolicited MOB_SLP-RSP message to the MS as described above. The operation mode of the MS is changed from an active mode to a sleep mode, and an uplink data acknowledgment message is transmitted to the MS in order to confirm a connection state between the BS and the MS in the sleep mode. Next, in step S335, the BS checks whether the uplink band request message is received from the MS in response to the uplink data grant message transmitted in step S330, and confirms the access state with the MS again. Here, since the uplink band request message transmitted by the MS has been described in detail above, a detailed description thereof will be omitted.

As a result of the check in step S330, if the MS does not receive an uplink bandwidth request message from the MS, it determines that the connection with the MS has been terminated, and proceeds to step S340. In step S340, the BS deletes the information on the disconnected MS. That is, the MS reinitialize error of the MS, thus deleting the information on the MS acquired during the initial connection with the MS to prevent waste of the BS's own memory and the CID allocated to the MS when the information on the MS is stored. do. At this time, if a connection request is received from the disconnected MS, an initial access procedure is performed with the MS.

On the other hand, when the check result in step S315, the BS receives data from the MS, since the connection with the MS is maintained in the active mode, the process proceeds to step S350, in step S350 BS is sent to the MS in the active mode Normal operation, for example, resource allocation for data transmission and reception with the MS, transmission power control, and MCS level control.

If the control message is received in step S325, the BS checks the header of the received control message in step S345, that is, as described above, the bandwidth request header and the uplink transmission power report header or the PHY channel report header. Alternatively, by checking the extended subheader of the high-capacity transmission power report, the received control message is received from the MS to check the connection state, that is, a control message received from the MS transmitting and receiving data in the active mode with itself in step S305. Check if it is a control message. In other words, in step S345, the BS checks the TLV of the bandwidth allocation request message, the uplink transmission power report message, and the uplink transmission power control request message header to transmit the bandwidth allocation request message, the uplink transmission power report message, and the uplink transmission. Check whether the MS sending the power control request message is the MS to check the connection state.

As a result of the check in step S345, if the control message is received from the MS to check the connection state, the BS proceeds to step S350 as the connection with the MS is maintained in the active mode, and in step S350 the BS is As described above, the MS performs a normal operation on the MS. On the other hand, if it is determined in step S345 that the control message is not received from the MS to check the connection state, that is, the control message received in step S325 is transmitted by another MS other than the MS to check the connection state As a message, the BS confirms that it has not received a control message from the MS to check the access state, and proceeds to step S330. In step S330, the BS transmits an Unsolicited MOB_SLP-RSP message to the MS. The operation mode of the MS is changed from an active mode to a sleep mode, and an uplink data acknowledgment message is transmitted to the MS in the sleep mode.

In addition, if it is determined in step S335 that an uplink bandwidth request message is received from the MS, that is, the connection with the MS is maintained, the BS maintains the connection with the MS in the active mode as described above. In step S350, the BS performs a normal operation on the MS.

Thus, even if the communication system according to another embodiment of the present invention does not receive data from the MS for more than a predetermined time in the active mode and cannot check the connection state through the reception of the data, the control message transmitted from the MS, namely Confirms whether a bandwidth allocation request message, an uplink transmission power report message, and an uplink transmission power control request message are received, and receives the control message from an MS to confirm a connection state through a header of the received control message. Check whether the message is received to confirm the MS sending the control message and the connection status with the MS. In addition, even if the control message is not received in the active mode, the MS transmits an Unsolicited MOB_SLP-RSP message to switch the operation mode of the MS from the active mode to the sleep mode. After transmitting, in response to the uplink data acknowledgment message, it is checked whether an uplink bandwidth request message is received to confirm a connection state with the MS. This prevents wasting of the BS's memory and CIDs assigned to the MS according to the storage of information about the MS and improves the reliability of the communication. Next, the operation of the BS in the communication system according to another embodiment of the present invention will be described in more detail with reference to FIG. 4.

4 is a diagram illustrating an operation process of a BS in a communication system according to another embodiment of the present invention.

Referring to FIG. 4, first, in step S405, the BS operates in an active mode with an MS, that is, performs data transmission / reception with the MS. Next, in step S410, the BS transmits a UCD / MAP message including feedback area information or feedback allocation information elements (IE) (hereinafter, referred to as 'IE') to the MS. Then, in step S415, the BS checks whether data is received from the MS during a predetermined time through a resource allocated to the MS, for example, during a data reception period, that is, whether data is received from the MS in an active mode. Check the connection status with the MS. As a result of the check in step S415, if the data is not received from the MS, that is, if there is no data from the MS for a time longer than the data reception interval in the active mode, it is determined that the connection with the MS is disconnected, and the procedure proceeds to step S420. In step S420, the BS checks the availability of the CQICH, which is a feedback channel allocated exclusively to the MS after the initial access procedure with the MS. Here, the CQICH is a channel allocated exclusively for receiving the CQI of the downlink from the MS when the scheduling for transmitting and receiving data with the BS, that is, a process in which the BS allocates the CQICH to the MS as a feedback channel. Since it is not directly related to the present invention, a detailed description thereof will be omitted herein.

If it is determined in step S420 that the CQICH allocated to the MS is not available, the process proceeds to step S425. In step S425, the BS sends a REP-REQ message so that the MS transmits a downlink CQI to the BS. Send to MS. Upon receiving the REP-REQ message, the MS measures the downlink channel state between the MS itself and the BS, for example, Received Signal Strength Indication (RSSI) from the BS in downlink. , Signal to Interference and Noise Ratio (SINR), or Carrier to Interference and Noise Ratio (CINR). After measuring and generating a CQI, a REP-RSP message including the CQI is transmitted to the BS. Then, in step S430, the BS receives the REP-RSP message transmitted by the MS, and then proceeds to step S435.

In step S435, the BS performs a cyclic redundancy check (CRC: Cyclic Redundancy Check, hereinafter referred to as 'CRC') between the REP-REQ message transmitted to the MS and the REP-RSP message received from the MS. Check whether the same as the CRC, that is, the BS checks whether there is no error in the REP-RSP message received from the MS in response to the REP-REQ message sent by the BS and the REP-REQ message transmitted in step S425 and the S430 Check whether the REP-RSP message received in step is a message transmitted and received normally without error. As a result of checking in step S435, if the REP-REQ message and the REP-RSP message are normally transmitted and received, the BS proceeds to step S440. In step S440, the BS receives the CID of the MS that received the REP-REQ message. And the CID of the MS sending the REP-RSP message to determine whether the MS receiving the REP-REQ message is identical to the MS sending the REP-RSP message.

If the MS receiving the REP-REQ message and the MS transmitting the REP-RSP message are the same as the result of the check in step S440, that is, the MS sends the REP-RSP in response to the REP-REQ message received from the BS. If the BS transmits a message to the BS and the BS receives the REP-RSP message, the BS proceeds to step S445 in which the connection with the MS is maintained in an active mode, and the BS proceeds to step S445 as described above. Perform a normal operation on the MS in the active mode.

On the other hand, as a result of the check in step S435, if the REP-REQ message transmitted in step S425 and the REP-RSP message received in step S430 is not a message normally transmitted and received without error, that is, the REP received in step S430 If the CQI included in the REP-RSP message cannot be decrypted as a result of the CRC of the RSP message, the received REP-RSP message is determined to be an interference message, and the BS receives the REP-RSP message from the MS to check the connection status. In step S455, the BS transmits an Unsolicited MOB_SLP-RSP message to the MS as described above. In the sleep mode, and transmits an uplink data acknowledgment message to the MS to confirm the connection state between the BS and the MS in the sleep mode. The.

Next, in step S460, the BS checks whether an uplink band request message is received from the MS in response to the uplink data acknowledgment message transmitted in step S455, and confirms the access state with the MS again. Here, since the uplink band request message transmitted by the MS has been described in detail above, a detailed description thereof will be omitted.

As a result of the check in step S460, if the MS does not receive the uplink band request message, the MS determines that the connection with the MS is terminated, and proceeds to step S465. In step S465, the BS deletes the information on the disconnected MS. That is, the MS reinitialize error of the MS, thereby deleting the information on the MS acquired during the initial connection with the MS to prevent waste of BS's own memory and CID allocated to the MS by storing the information on the MS. do. At this time, if a connection request is received from the disconnected MS, an initial access procedure is performed with the MS. On the other hand, if the check result in step S460, when receiving the uplink band request message from the MS, that is, the connection with the MS is maintained, the BS is a state in which the connection of the MS in the sleep mode is maintained in step S445 In step S445, the BS performs a normal operation on the MS, for example, a normal operation on the MS in a sleep mode.

If the MS that has received the REP-REQ message and the MS that has transmitted the REP-RSP message are different from each other, that is, in response to the REP-REQ message transmitted by the BS, the REP− If the RSP message is not received, the REP-RSP message received in step S430 is not a REP-RSP message received from the MS to check the connection status, that is, transmitted by another MS other than the MS to check the connection status. The BS determines that the connection with the MS is disconnected because the BS has not received the REP-RSP message from the MS to check the connection state, and proceeds to step S455. By sending an Unsolicited MOB_SLP-RSP message to the MS, the operation mode of the MS is changed from the active mode to the sleep mode, and the uplink data acknowledgment message is sent to the MS. Send.

In addition, if it is determined in step S420 that the CQICH allocated to the MS is available, the process proceeds to step S450. In step S450, the BS receives the CQI from the MS through the CQICH exclusively assigned to the MS. Check whether or not. Here, the BS allocates the CQICH to the MS during scheduling as described above, and the allocation information of the CQICH is assigned to the MAP message transmitted in step 410, in particular, an uplink-MAP (UL (UpLink))-MAP) message. It is included and sent to the MS. Accordingly, the MS checks its CQICH allocation information included in the MAP-message, and then transmits the CQI generated as described above to the BS through the CQICH. Then, in step S450, the BS checks whether the CQI is received from the MS through the CQICH.

As a result of the check in step S450, when the CQI is received through the CQICH, the BS is a dedicated channel of the MS for which the CQICH is to check the access status, and the CQI received through the CQICH indicates that the MS to check the access status is determined. Confirming that the transmission is a CQI, that is, the BS confirms that the connection with the MS in the active mode is maintained, and proceeds to step S445, and in step S445, the BS performs a normal operation on the MS in the active mode as described above. To perform. On the other hand, as a result of the check in step S450, if the CQI is not received via the CQICH, the connection with the MS is disconnected and the BS proceeds to step S455, and in step S455 the BS goes to the MS as described above. The MS transmits an Unsolicited MOB_SLP-RSP message to change the operation mode of the MS from the active mode to the sleep mode, and transmits the uplink data acknowledgment message to the MS.

Thus, even in the communication system according to another embodiment of the present invention to receive a CQI from the MS, even if it is unable to receive data from the MS for a predetermined time or more in the active mode and cannot confirm the connection state through the reception of the data. Confirmation of the MS and the MS to check the connection state by checking whether the REP-REQ / REP-RSP message is transmitted or received with the MS or receiving the CQI through the CQICH exclusively assigned to the MS. Check the connection status. In addition, even if the control message is not received in the active mode, the MS transmits an Unsolicited MOB_SLP-RSP message to switch the operation mode of the MS from the active mode to the sleep mode. After transmitting, in response to the uplink data acknowledgment message, it is checked whether an uplink bandwidth request message is received to confirm a connection state with the MS. This prevents wasting of the BS's memory and CIDs assigned to the MS according to the storage of information about the MS and improves the reliability of the communication. Next, the operation of the BS in the communication system according to another embodiment of the present invention will be described in detail with reference to FIG. 5.

5 is a diagram illustrating an operation process of a BS in a communication system according to another embodiment of the present invention.

Referring to FIG. 5, in step S505, the BS checks whether the MS is in an active mode operation. As a result of the checking in step S505, when the MS operates in the active mode with the MS, in step S510, the BS checks whether the uplink data is received, that is, during a predetermined time through a resource allocated to the MS, for example, during the data receiving period. Check the connection status with the MS by checking whether data is received from the MS. In addition, in step S515, the BS confirms whether the MS reports on the uplink transmission power to confirm a connection state with the MS, or in step S520, whether the CQI is reported from the MS.

Here, whether the BS receives uplink data, reports whether the uplink transmission power is reported, or whether the CQI is reported, the confirmation priority is determined according to the reception order in the uplink, and embodiments of the present invention provide convenience of description. For the purpose of checking whether uplink transmission power is reported or whether CQI is reported after checking whether uplink data is received, but confirming whether to receive uplink data after confirming whether to report uplink transmission power or CQI. The same applies to the present invention. In addition, if the BS does not receive the uplink data as a result of the check in step S510, the BS proceeds to step S515 or S520 to determine whether to report the uplink transmission power or CQI report, and as a result of the check in step S515 If the uplink transmission power is not received, the process proceeds to step S520 to determine whether to report the CQI. Here, in the embodiments of the present invention, if the uplink data is not received for convenience of explanation, the description will be made based on checking whether the uplink transmission power is reported and then checking whether the CQI is reported. The same applies to the case of checking whether the UL transmission power is reported after checking.

When receiving the uplink data as a result of the check in step S510, the process proceeds to step S525. In step S525, the BS transmits the base CID (BCID: MS) of the MS whose CID of the MS has transmitted the uplink data. Basic CID, hereinafter referred to as 'BCID'), or Primary Management CID (PMCID: Primary Management CID, hereinafter referred to as 'PMCID'), or Transport CID (TCID: Transport CID, hereinafter referred to as 'TCID') Check if it is same as If the CID of the MS that has transmitted the uplink data is different from the BCID, PMCID, or TCID of the MS to check the access status, the BS proceeds to step S515 or S520 and uplinks. It is checked whether the transmission power is reported or whether the CQI is reported. If the uplink transmission power is not reported as a result of the checking in step S515, the process proceeds to step S520 to check whether the CQI is reported.

On the other hand, if the check result in step S525, the CID of the MS that transmitted the uplink data is the same as the BCID, PMCID, or TCID of the MS to check the connection state, and confirms that the connection with the MS is maintained S530 In step S530, the BS checks the uplink transmission power and the CQI of the MS to check the access state. Then, in step S535, the BS maintains a connection with the MS and thus performs a normal operation on the MS as described above.

In addition, if the CQI is not reported as a result of the check in step S520, the BS proceeds to step S540, and in step S540, the BS performs a power saving class (PSC) for reducing power consumption with the MS. Type), that is, by sending an Unsolicited MOB_SLP-RSP message to the MS to determine whether it is possible to switch the operation mode of the MS from the active mode to the sleep mode.

If the PSC type is not determined in step S540, the BS proceeds to step S545. In step S545, the BS transmits an uplink data grant message to the MS. Here, the BS transmits the uplink data grant message to the MS as described above in step S230 of FIG. 2 so that the MS transmits uplink data, that is, unicast data, to the BS. Then, in step S550, the BS receives uplink data, that is, unicast data from the MS. At this time, if there is unicast data to be transmitted to the BS, the MS transmits the unicast data to the BS in response to the uplink data acknowledgment message, and there is no unicast data to be transmitted to the BS. Otherwise, transmits the padded data unit to the BS in response to the uplink data grant message.

Next, in step S555, the BS checks whether the CID of the MS that has transmitted the unicast data is the same as the BCID, PMCID, or TCID of the MS to which the MS is to be connected. If the CID of the MS that has transmitted the unicast data is different from the BCID, PMCID, or TCID of the MS to check the connection status, the MS determines that the connection with the MS is disconnected. Then, in step S560, the BS deletes the information on the MS that is disconnected as described above, that is, the MS re-initialization error, so that the BS deletes the information on the MS acquired during the initial connection with the MS. It prevents the BS's own memory and the CIDs allocated to the MSs from being stored. At this time, if a connection request is received from the disconnected MS, an initial access procedure is performed with the MS.

On the other hand, the CID of the MS that has received the confirmation result uplink transmission power in step S515, reports the result CQI in step S520, or the result of the check in step S555, transmits the unicast data in the access state. If it is the same as the BCID, PMCID, or TCID of the MS to check, the BS checks that the connection is maintained and the BS proceeds to step S530, and in step S530, the BS checks the connection state as described above. After checking the uplink transmission power and the CQI of the MS to be performed, the process proceeds to step S535.

If the PSC type is determined in step S540, the BS proceeds to step S565. In step S565, the BS transmits an Unsolicited MOB_SLP-RSP message to the MS to sleep the operating mode of the MS in the active mode. Switch to the mode. Then, in step S570, the BS checks the reception period of the MS for the uplink data acknowledgment message transmitted to confirm the connection state with the MS in the sleep mode, and receives the confirmed acknowledgment of the uplink data acknowledgment message. Transmit in the possible section. Then, in step S575, the BS receives uplink data in response to the uplink data grant message. In this case, the BS receives an uplink band request message from the MS in response to an uplink data grant message, or a unicast including unicast data, that is, a data unit to be actually transmitted to the BS, instead of a padded data unit. Receive the unicast data set to '0' because the data unit or the data unit to be actually transmitted does not exist.

Next, in step S580, the BS checks whether the CID of the MS that has transmitted the uplink data is the same as the BCID, PMCID, or TCID of the MS to check the access state. If the CID of the MS that has transmitted the uplink data is different from the BCID, PMCID, or TCID of the MS to check the access state as a result of the check in step S580, after confirming that the connection with the MS is disconnected, proceed to step S560. In step S560, the BS deletes information on the disconnected MS as described above.

On the other hand, when it is confirmed in step S505 that the MS operates in the sleep mode in step S570 as described above the BS for the uplink data acknowledgment message transmitted to confirm the connection state with the MS in the sleep mode as described above; The MS determines the reception period of the MS and transmits the uplink data acknowledgment message in the confirmation reception period. Then, in step S575, the BS receives uplink data in response to the uplink data grant message. At this time, the BS receives the uplink band request message or receives the actual transmission data unit or unicast data set to '0' and proceeds to step S580.

Then, in step S580, the BS checks whether the CID of the MS that has transmitted the uplink data is the same as the BCID, PMCID, or TCID of the MS to check the access state as described above. If it is determined that the connection is disconnected and proceeds to step S560, the BS in step S560 deletes information on the MS. On the other hand, if the CID of the MS that has transmitted the uplink data is the same as the BCID, PMCID, or TCID of the MS to check the access state, in step S580, the BS maintains the connection with the MS. Check and proceed to step S585, and check the uplink transmission power and the CQI of the MS to check the access state in step S585, and proceeds to step S570 to the upstream in the reception period of the uplink data approval message of the MS Send a link data acknowledgment message.

As described above, in the communication system according to another embodiment of the present invention, whether the uplink data is received from the MS in the active mode, whether the uplink transmission power is reported, or whether the CQI is reported, the access state is confirmed with the MS. Although the connection status with the MS cannot be confirmed by checking whether the link data is received, whether the UL transmission power is reported, or whether the CQI is reported, the MS is switched from the active mode to the sleep mode, and then the uplink from the MS is uplinked. The connection status with the MS is checked by checking whether link data is received. This prevents wasting of the BS's memory and CIDs assigned to the MS according to the storage of information about the MS and improves the reliability of the communication. Next, the operation of the BS in the communication system according to another embodiment of the present invention will be described in detail with reference to FIGS. 6 and 7. Herein, in another embodiment of the present invention described with reference to FIGS. 6 and 7, unlike the embodiment of the present invention described with reference to FIGS. 2 to 5, the operation mode switching is not supported when checking the connection state with the MS. When the BS sends an Unsolicited MOB_SLP-RSP message to the MS to switch the operating mode of the MS from the active mode to the sleep mode, the BS checks the connection state with the MS.

6 is a diagram illustrating an operation process of a BS in a communication system according to another embodiment of the present invention.

Referring to FIG. 6, in step S605, the BS determines whether the BS is in an active mode operation. As a result of the checking in step S605, when operating in the active mode with the MS, the BS checks whether the uplink data is received in step S610, that is, during a predetermined time through a resource allocated to the MS, for example, during the data receiving period. Check the connection status with the MS by checking whether data is received from the MS. In addition, in step S615, the BS checks whether the CQI is reported from the MS. In this case, whether the BS receives uplink data or reports CQI is determined according to the reception order in the uplink. The priority of the acknowledgment is determined according to the reception order in the uplink. The present invention will be described based on checking whether the CQI is reported after checking whether the data has been received, but the present invention is equally applicable to checking whether the UL data is received after checking the CQI.

When receiving the uplink data as a result of the check in step S610, the process proceeds to step S620, in step S620 BS BS, PMCID, or MS of the MS to which the CID of the MS that transmitted the uplink data to check the access state; Check if it is same as TCID. If the CID of the MS that has transmitted the uplink data is different from the BCID, PMCID, or TCID of the MS to check the access status, the BS proceeds to step S615 to check whether the CQI is reported. do.

On the other hand, if the check result in step S620, the CID of the MS that transmitted the uplink data is the same as the BCID, PMCID, or TCID of the MS to check the connection status, and confirms that the connection with the MS is maintained S625 In step S625, the BS checks the CQI of the MS to check the access state. Then, in step S630, the BS maintains a connection with the MS and thus performs a normal operation on the MS as described above.

In addition, if the CQI is not received as a result of the check in step S615, the BS proceeds to step S635, and in step S635, the BS transmits an uplink data grant message to the MS. Here, the BS transmits the uplink data grant message to the MS as described in step S545 of FIG. 5 so that the MS transmits uplink data, that is, unicast data, to the BS. Then, in step S640, the BS receives uplink data, that is, unicast data, from the MS. At this time, if there is unicast data to be transmitted to the BS, the MS transmits the unicast data to the BS in response to the uplink data acknowledgment message, and there is no unicast data to be transmitted to the BS. Otherwise, transmits the padded data unit to the BS in response to the uplink data grant message.

Next, in step S645, the BS checks whether the CID of the MS that transmitted the unicast data is the same as the BCID, PMCID, or TCID of the MS to which the MS is to be connected. If the CID of the MS that has transmitted the unicast data is different from the BCID, PMCID, or TCID of the MS for which the connection status is determined as the result of the check in step S645, it is determined that the connection with the MS is disconnected. Then, in step S650, the BS deletes the information on the MS disconnected as described above, that is, the MS re-initialization error, so that the BS deletes the information on the MS acquired during the initial connection with the MS information of the MS. It prevents the BS's own memory and the CIDs allocated to the MSs from being stored. At this time, if a connection request is received from the disconnected MS, an initial access procedure is performed with the MS.

On the other hand, the CQI is reported from the MS as a result of the check in step S615, or the CID of the MS that has transmitted the unicast data as a result of the check in step S645 and BCID, PMCID, or TCID of the MS to check the connection state. If it is the same, the MS checks that the connection is maintained with the MS, and the BS proceeds to step S625. In step S625, the BS checks the CQI of the MS to check the connection state as described above, and then proceeds to step S630. do.

In operation S605, when the MS operates in the sleep mode, the BS may receive the uplink data acknowledgment message that the BS transmits to confirm the connection state with the MS in the sleep mode. The interval is confirmed, and the uplink data acknowledgment message is transmitted in the confirmed receivable interval. Then, in step S660, the BS receives uplink data in response to the uplink data grant message. In this case, the BS receives an uplink band request message from the MS in response to an uplink data grant message, or a unicast including unicast data, that is, a data unit to be actually transmitted to the BS, instead of a padded data unit. Receive the data or receive the unicast data set to '0' because there is no data unit to actually transmit.

Next, in step S665, the BS checks whether the CID of the MS that has transmitted the uplink data is the same as the BCID, PMCID, or TCID of the MS to check the access state. If the CID of the MS that has transmitted the uplink data is different from the BCID, PMCID, or TCID of the MS to check the access state as a result of the check in step S665, it is determined that the connection with the MS has been disconnected. In step S650, the BS deletes information on the disconnected MS as described above.

On the other hand, if the CID of the MS that has transmitted the uplink data is the same as the BCID, PMCID, or TCID of the MS to check the access state, in step S665, the BS maintains connection with the MS. Check and proceed to step S670, and check the CQI of the MS to check the access state in step S670, and proceeds to step S655 to receive the uplink data acknowledgment message in the MS can receive the uplink data acknowledgment message. Send.

7 is a diagram illustrating an operation process of a BS in a communication system according to another embodiment of the present invention.

Referring to FIG. 7, in step S705, the BS determines whether the BS is in an active mode operation. As a result of the checking in step S705, when the MS operates in the active mode, the BS checks whether the uplink data is received in step S710, that is, during a predetermined time through a resource allocated to the MS, for example, during the data receiving period. Check the connection status with the MS by checking whether data is received from the MS. In addition, in step S715, the BS checks whether the MS reports on the uplink transmission power to confirm a connection state with the MS, or in step S720, checks whether the CQI is reported from the MS. If the BS does not receive the uplink data as a result of the check in step S710, the BS proceeds to step S715 or S720 to determine whether to report the uplink transmission power or the CQI report. If the uplink transmission power is not received, the process proceeds to step S720 to determine whether the CQI is reported.

Here, whether the BS receives uplink data, reports whether the uplink transmission power is reported, or whether the CQI is reported, the confirmation priority is determined according to the reception order in the uplink as described above. If one of the following checks is performed, whether the UL transmission power is reported, or whether the CQI is reported, then one of the others is not received or not received, and the other one is not received or not received. Check the connection status.

When receiving the uplink data as a result of the check in step S710, the process proceeds to step S725, in step S725 BS BS, PMCID, or MS of the MS to which the CID of the MS that transmitted the uplink data to check the access state Check if it is same as TCID. If the CID of the MS that has transmitted the uplink data is different from the BCID, PMCID, or TCID of the MS to check the access state as a result of the checking in step S625, the BS proceeds to step S715 or S720 and uplinks. It is checked whether the transmission power is reported or whether the CQI is reported. If the uplink transmission power is not reported as a result of the checking in step S715, the process proceeds to step S720 to determine whether the CQI is reported.

On the other hand, if the check result in step S725, the CID of the MS transmitting the uplink data is the same as the BCID, PMCID, or TCID of the MS to check the connection state, and checks the connection is maintained with the MS S730 In step S730, the BS checks the uplink transmission power and the CQI of the MS to check the access state. Then, in step S735, the BS maintains a connection with the MS and thus performs a normal operation on the MS as described above.

In addition, if the CQI is not received as a result of the check in step S720, the BS proceeds to step S740, and in step S740, the BS transmits an uplink data grant message to the MS. Here, the BS transmits the uplink data grant message to the MS as described in step S545 of FIG. 5 so that the MS transmits uplink data, that is, unicast data, to the BS. Then, in step S745 the BS receives uplink data, that is, unicast data from the MS. At this time, if there is unicast data to be transmitted to the BS, the MS transmits the unicast data to the BS in response to the uplink data acknowledgment message, and there is no unicast data to be transmitted to the BS. Otherwise, transmits the padded data unit to the BS in response to the uplink data grant message.

Next, in step S750, the BS checks whether the CID of the MS that has transmitted the unicast data is the same as the BCID, PMCID, or TCID of the MS to which the MS is to be connected. If the CID of the MS that has transmitted the unicast data is different from the BCID, PMCID, or TCID of the MS for which the connection status is determined as the result of the check in step S750, the process determines that the connection with the MS is disconnected. Then, in step S755, the BS deletes the information on the disconnected MS as described above, that is, the MS re-initialization error, so that the BS deletes the information on the MS acquired during the initial connection with the MS. It prevents the BS's own memory and the CIDs allocated to the MSs from being stored. At this time, if a connection request is received from the disconnected MS, an initial access procedure is performed with the MS.

On the other hand, the MS as a result of confirmation in step S715 reports uplink transmission power from the MS, or in step S720 receives a CQI report from the MS, or in step S750 as a result of the confirmation MS transmitted the unicast data If the CID of the MS is the same as the BCID, PMCID, or TCID of the MS to check the access state, the connection with the MS is maintained and the BS proceeds to step S730, and the BS proceeds to step S730 as described above. After checking the uplink transmission power and the CQI of the MS to check the access state, the process proceeds to step S735.

In operation S705, when the MS operates in the sleep mode, the BS may receive the MS for an uplink data acknowledgment message transmitted by the BS in order to confirm a connection state with the MS in the sleep mode. The interval is confirmed, and the uplink data acknowledgment message is transmitted in the confirmed receivable interval. Then, in step S765, the BS receives uplink data in response to the uplink data grant message. In this case, the BS receives an uplink band request message from the MS in response to an uplink data grant message, or a unicast including unicast data, that is, a data unit to be actually transmitted to the BS, instead of a padded data unit. Receive the data or receive the unicast data set to '0' because there is no data unit to actually transmit.

Next, in step S770, the BS checks whether the CID of the MS that transmitted the uplink data is the same as the BCID, PMCID, or TCID of the MS to check the access state. If the CID of the MS that has transmitted the uplink data is different from the BCID, PMCID, or TCID of the MS to check the access status as a result of the check in step S770, the procedure is determined to be disconnected from the MS. In step S755, the BS deletes information on the disconnected MS as described above.

On the other hand, if the CID of the MS that has transmitted the uplink data is the same as the BCID, PMCID, or TCID of the MS to check the access state, in step S770, the BS maintains the connection with the MS. Check and proceed to step S785, and check the CQI of the MS to check the access state in step S785, and proceeds to step S760 and the uplink data acknowledgment message in the uplink data acknowledgment message reception period of the MS Send.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by the equivalents of the claims.

1 schematically illustrates the structure of a communication system according to an embodiment of the invention.

2 is a diagram illustrating an operation of a BS in a communication system according to an embodiment of the present invention.

3 is a diagram illustrating an operation process of a BS in a communication system according to another embodiment of the present invention.

4 is a diagram illustrating an operation of a BS in a communication system according to another embodiment of the present invention.

5 is a diagram illustrating an operation of a BS in a communication system according to another embodiment of the present invention.

6 is a diagram illustrating an operation process of a BS in a communication system according to another embodiment of the present invention.

7 is a diagram illustrating an operation process of a BS in a communication system according to another embodiment of the present invention.

Claims (28)

A communication system comprising a base station and a mobile station provided with a service from the base station, the method of the base station confirming the connection with the mobile station, Checking whether data is received from the mobile station operating in an active mode; If the data is not received for a predetermined time or more, confirming whether the mobile station has received at least one of a bandwidth allocation request message, an uplink transmission power report message, and an uplink transmission power control request message; Confirming that the connection with the mobile station is maintained when the at least one message is received. The method of claim 1, The step of checking whether the at least one message is received may include checking whether a header of the at least one message is the same between a mobile station that has transmitted the at least one message and a mobile station that wants to check a connection state. Connection confirmation method. The method of claim 1, If no data is received from the mobile station, the mobile station transmits an uplink data acknowledgment message to the mobile station, and then checks whether the uplink data is received in response to the uplink data acknowledgment message. And confirming the connection with the connection is maintained. The method of claim 3, The step of confirming whether the uplink data is received, checks whether the connection identifier of the mobile station that has transmitted the uplink data is identical to the connection identifier of the mobile station to confirm the connection status. The method of claim 1, If the at least one message is not received, an unsolicited sleep response message is transmitted to the mobile station to switch the operation mode of the mobile station to a sleep mode, and then the uplink data acknowledgment message is transmitted. And checking whether an uplink bandwidth request message has been received in response to the request. The method of claim 1, The step of checking whether the at least one message is received may include: confirming that the connection with the mobile station is maintained when receiving the uplink bandwidth allocation request information or the uplink bandwidth request message with '0' set from the mobile station. Connection confirmation method characterized in that. A communication system comprising a base station and a mobile station provided with a service from the base station, the method of the base station confirming the connection with the mobile station, Checking whether data is received from the mobile station operating in an active mode; Checking whether a report response message is received from the mobile station or receiving channel quality information through a feedback channel from the mobile station if data is not received from the mobile station for a predetermined time or more; When receiving the report response message or the channel quality information, confirming that the connection with the mobile station is maintained. The method of claim 7, wherein The step of confirming whether the report response message is received, the connection confirmation method characterized in that by performing a cyclic redundancy check of the report response message. The method of claim 7, wherein The step of confirming whether the report response message has been received may include checking a connection identifier of the mobile station receiving the report request message and a connection identifier of the mobile station transmitting the report response message to determine a connection state with the mobile station that has sent the report response message. And confirming whether or not the mobile stations to be identified are identical. The method of claim 7, wherein The checking of the report response message may include determining whether the channel quality information included in the report response message is correctly decoded. The method of claim 7, wherein The step of confirming whether the channel quality information is received, checks whether the mobile station that has transmitted the channel quality information through the feedback channel is identical to the mobile station to check the connection status. A communication system comprising a base station and a mobile station provided with a service from the base station, the method of the base station confirming the connection with the mobile station, Checking whether data is received from the mobile station in an active mode; If data is not received from the mobile station for a predetermined time or more, confirming connection maintenance with the mobile station according to whether a response message to the uplink data acknowledgment message or a channel quality information message indicating channel quality is received. Connection confirmation method characterized in that. The method of claim 12, If the response message or the channel quality information message is not received, transmitting a sleep mode switch request message to the mobile station, and confirming whether to receive an uplink bandwidth request message in response to the uplink data grant message; Connection confirmation method further comprises. The method of claim 13, The step of confirming whether the uplink bandwidth request message is received may include: confirming that the connection with the mobile station is maintained when receiving the uplink bandwidth request information or the uplink bandwidth request message with '0' set from the mobile station. Connection confirmation method characterized in that. In the system to check the connection, Base station, A mobile station provided with the service from the base station and operating in an active mode, The base station confirms whether data is received from the mobile station, and if the data is not received for a predetermined time or more, at least one of a bandwidth allocation request message, an uplink transmission power report message, and an uplink transmission power control request message from the mobile station. And confirming reception of the message, and confirming that the connection with the mobile station is maintained when the at least one message is received. The method of claim 15, And the base station checks the header of the at least one message and confirms whether the mobile station which has transmitted the at least one message is identical to the mobile station to which the mobile station is to be connected. The method of claim 15, If the base station does not receive data from the mobile station, the base station transmits an uplink data grant message to the mobile station and then checks whether uplink data has been received in response to the uplink data grant message, and transmits the uplink data. And confirming that the connection with the mobile station is maintained upon receipt. The method of claim 17, And the base station confirms whether the connection identifier of the mobile station that has transmitted the uplink data is identical to the connection identifier of the mobile station to which the mobile station is to be connected. The method of claim 15, If the base station does not receive the at least one message, the base station transmits an unsolicited sleep response message to the mobile station to switch the operation mode of the mobile station to a sleep mode, and then transmits the uplink data acknowledgment message, and the uplink. And checking whether an uplink bandwidth request message is received in response to the data acknowledgment message. The method of claim 15, The base station determines whether the at least one message is received and confirms that the connection with the mobile station is maintained when receiving the uplink bandwidth request information or the uplink bandwidth request message with '0' set from the mobile station. Connection confirmation system, characterized in that. In the system to check the connection, Base station, A mobile station provided with the service from the base station and operating in an active mode, The base station confirms whether data is received from the mobile station, and if it does not receive data from the mobile station for a predetermined time or more, checks whether a report response message is received from the mobile station or channel quality information through a feedback channel from the mobile station. And confirming reception of the message, and confirming that the connection with the mobile station is maintained when the report response message or the channel quality information is received. The method of claim 21, And the base station confirms whether the report response message is received by performing a cyclic redundancy check of the report response message. The method of claim 21, The base station checks the connection identifier of the mobile station that receives the report request message and the connection identifier of the mobile station that transmits the report response message to confirm whether the mobile station that has sent the report response message is identical to the mobile station that wants to confirm the connection state. Connection confirmation system, characterized in that. The method of claim 21, And the base station confirms whether the channel quality information included in the report response message is correctly decoded. The method of claim 21, And the base station confirms whether the mobile station which has transmitted the channel quality information through the feedback channel is identical to the mobile station to which the mobile station is to be connected. In the system to check the connection, Base station, A mobile station provided with the service from the base station and operating in an active mode, The base station confirms whether data is received from the mobile station, and if it does not receive data from the mobile station for a predetermined time or more, whether the base station receives a response message or a channel quality information message indicating a channel quality. And confirming the maintenance of the connection with the mobile station. The method of claim 26, If the base station does not receive the response message or the channel quality information message, the base station transmits a sleep mode switch request message to the mobile station, and confirms whether to receive the uplink bandwidth request message in response to the uplink data grant message. Connection confirmation system, characterized in that. The method of claim 27, And when the base station receives the uplink bandwidth request information or the uplink bandwidth request message with '0' set from the mobile station, confirms that the connection with the mobile station is maintained.

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