KR100527636B1 - Method for controlling sleep mode of ofdma/tdma-based mobile data network - Google Patents

Abstract

The present invention relates to a sleep mode control method for an OFDMA / TDMA based mobile data network.

In the sleep mode control method of an OFDMA / TDMA-based mobile data network according to the present invention, the base station associates a sleep mode CDMA code with a sleep mode multicasting group to a terminal that switches to sleep mode for sleep mode CDMA code and sleep mode. The multicasting CID is allocated to the terminal. When the downlink data to be transmitted to the terminal in the sleep mode arrives, the multicasting CID of the multicasting group to which the terminal belongs is searched for and stored in the buffer of the retrieved multicasting CID. When receiving the CDMA code for the sleep mode from the terminal, the base station determines the terminal modem parameter value according to the received power of the terminal and is currently downgraded from the multicasting CID corresponding to the sleep mode CDMA code in the response message for the sleep mode CDMA code. Data to be transmitted to the link is transmitted including the ID of the terminal waiting for it and the value of the terminal modem parameter.

In this way, transmission without loss of downlink data can be guaranteed.

Description

Method for controlling sleep mode of ODFMAA / TDMMA based mobile data network {METHOD FOR CONTROLLING SLEEP MODE OF OFDMA / TDMA-BASED MOBILE DATA NETWORK}

The present invention provides the complexity of a base station (Access Point, hereinafter called AP) in a mobile data network based on Orthogonal Frequency Division Multiplexing Access / Time Division Multiple Access (hereinafter referred to as "OFDMA / TDMA"). The present invention relates to a sleep mode control method for reducing power consumption of a terminal.

For the implementation of wireless broadband multimedia system capable of high-speed reliability and large capacity service, OFDM transmission method that can send signals at high data rates in time division multiple access wireless channels mainly in the millimeter wave band from several GHz to several tens of GHz is spotlighted. Is getting.

1 is a diagram illustrating a conventional OFDMA / TDMA based sleep mode control method such as IEEE 802.16e.

Referring to FIG. 1, an operation of an access terminal (AT) includes a wake interval P _awake , a sleep interval P _sleep , and a listening interval P _listening . .

The normal period P _awake is a normal mode operation period in which data transmission and reception is possible, and the sleep period P _sleep is a sleep mode operation period to save power of the terminal. A listening period (P _listening ) is an operation period for informing the terminal in the sleep mode of the AP that there is currently downlink data to be transmitted and receiving the terminal.

When there is no transmission / reception of up / down data for a predetermined time, the terminal switches to the sleep mode to save power consumption of the terminal. This sleep mode time is exponentially increased when there is no transmission of up / down data in the listening interval P _listening .

The UE transmits a Sleep_Request (Sleep_REQ) message to the AP in order to switch to the sleep mode (S100). The Sleep_Request message includes maximum / minimum sleep interval information and time information. Upon receiving the Sleep_Request message from the terminal, the AP transmits a Sleep_Response (Sleep_RSP) message including the sleep mode switch start point and the listening interval information to the terminal (S110). After receiving the Sleep_Response message received from the AP, the UE switches to the sleep mode.

And AP is the Traffic_Indication message 12. When the terminal is downlink data is present to send to calculate the listening interval of the terminals (P _listening), and including the ID (identifier) of a terminal in a listening interval (P _listening) in the sleep mode, Broadcast to all terminals (S120).

Meanwhile, when the _{sleep period} P _sleep expires, the terminal switches to the listening mode and receives a Traffic_Indication message broadcast from the AP during the _listening period P _listening (S130). At this time, when the terminal includes its ID in the Traffic_Indication message, the terminal switches to the normal mode to receive the downlink data, and when the terminal does not include the ID in the Traffic_Indication message and the listening period (P _listening ) expires, The sleep mode (P _sleep ) is operated again in the sleep mode.

In the conventional OFDMA / TDMA-based sleep mode control method, the AP needs to calculate sleep intervals (P _sleep ) and listening intervals (P _listening ) of all terminals in the sleep mode, thereby increasing the complexity of the AP. And the sleep interval (P _sleep) sleep time is dynamically adjusted and increases the listening interval (P _listening) the power of a terminal in a listening interval (P _listening) consumption, so accordingly, the listening interval between the terminal and the AP (P _listening) If there is a mismatch or a Traffic_indication message is lost, the UE continues to operate in a sleep mode and thus cannot receive downlink data.

In the OFDMA / TDMA-based mobile data network, the transmission power according to the movement of the terminal and the data transmission time according to the distance between the terminal and the AP are required. To this end, periodic ranging is performed in an OFDMA / TDMA based mobile data network.

2 illustrates a periodic ranging procedure in the conventional OFDMA / TDMA 802.16e.

Referring to FIG. 2, when a periodic ranging interval (P _ranging ) expires, the terminal transmits a code division multiple access (CDMA) code to the AP in a competitive manner (S200). The AP receives the CDMA code, measures transmission power and arrival time, and transmits the adjusted value according to the RNG_RSP message to the terminal (S210). The terminal adjusts the transmission power and time according to the adjustment information included in the RNG_RSP message, which is repeated periodically.

As described above, in the conventional OFDMA / TDMA-based mobile data network, sleep mode control and periodic ranging are performed separately. That is, as shown in FIG. 1, when the terminal is in the sleep mode state, linkage with periodic ranging is not mentioned. If periodic ranging is not performed in the sleep mode, when the UE switches from the sleep mode to the normal mode and transmits and receives data, it is difficult to transmit data to the AP normally due to inaccurate transmission power and time.

In addition, when ranging from the sleep mode to the normal mode and performing the ranging, the data transmission delay is increased and the buffer capacity for data storage is increased. In addition, when the sleep mode and the ranging are performed independently, there is a problem in that power consumption saving according to the sleep mode is reduced.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above problems, and an aspect of the present invention is to provide a sleep mode control method for an OFDMA / TDMA based mobile data network that can reduce the complexity of controlling sleep mode and listening mode time of each terminal in an AP. It is to provide.

In addition, another technical problem to be achieved by the present invention is OFDMA / TDMA for efficiently managing the buffer for storing data to be transmitted from the AP to the terminal according to the loss of the traffic indication and to ensure the transmission without loss of downlink data to the terminal The present invention provides a method of controlling a sleep mode of an based mobile data network.

In order to solve this problem, the present invention provides a sleep mode control method of a terminal wirelessly connected to a base station in an orthogonal frequency division multiplexing access / time division multiple access (OFDMA / TDMA) based mobile data network.

According to an aspect of the present invention, there is provided a sleep mode control method of an OFDMA / TDMA-based mobile data network, the method comprising: a) requesting the base station to switch to sleep mode; b) receiving a response according to the request, wherein the response includes a code division multiple access (CDMA) code for sleep mode and a multicasting caller-ID (CID) for sleep mode; c) when the sleep mode is completed, transmitting the sleep mode CDMA code to the base station based on whether the sleep mode multicasting CID to which the sleep mode belongs is received from the base station; And d) receiving a response according to the CDMA code transmission for the sleep mode from the base station after step c) and performing ranging based on the response. At this time, the sleep mode CDMA code in step c) is transmitted to the base station when the multicasting CID to which it belongs is not received in step c).

The step d) may include: d-1) receiving a multicasting ranging response message according to CDMA code transmission for sleep mode from step c); And d-2) adjusting a modem parameter value based on the multicasting ranging response message, wherein step b) comprises: a CDMA code for the sleep mode from a response according to the request to switch to the sleep mode; Detecting and storing the multicasting CID for the sleep mode; Determining a sleep interval for switching to the sleep mode and setting a sleep time; And operating in a sleep mode during the set sleep time in the determined sleep period.

In addition, when receiving the sleep mode multicasting CID in step c), e) determining whether its ID is included in the sleep mode multicasting CID; And f) re-determining a sleep interval and comparing the re-determined sleep interval with a predetermined periodic ranging interval when the e-ID does not include the sleep mode multicasting CID in step e). can do.

And step d) is performed more than once within the periodic ranging period.

The present invention provides a method for controlling a sleep mode of a terminal in a base station wirelessly connected to the terminal in an orthogonal frequency division multiplexing access / time division multiple access (OFDMA / TDMA) based mobile data network.

According to another aspect of the present invention, a sleep mode control method for an OFDMA / TDMA based mobile data network includes a) a code division multiple access (CDMA) code for sleep mode and a multicasting caller-ID for sleep mode to the terminal; Assigning; b) upon receipt of a request to switch to sleep mode from the terminal, transmitting a response according to the request, wherein the response includes the assigned CDMA code for sleep mode and multicasting CID for sleep mode; ; c) searching for the multicasting CID to which the terminal belongs when the downlink data to be transmitted to the terminal currently in the sleep mode arrives; And d) transmitting the retrieved multicasting CID together with the downlink data to the terminal. At this time, if the terminal does not receive the multicasting CID to which it belongs in step d), receiving a sleep mode CDMA code transmitted from the terminal; Determining a terminal modem parameter value based on the received CDMA code; And transmitting, together with the downlink data, a terminal ID of the determined terminal modem parameter value and a downlink data to be currently transmitted in the multicasting CID belonging to the CDMA code for the sleep mode.

The corresponding terminal ID may be stored in the allocated buffer of the searched multicasting CID in step c), and the sleep mode CDMA code is determined based on whether the terminal receives the multicasting CID in step c). The CDMA code for the sleep mode is transmitted from the terminal at least once within the periodic ranging period for adjusting the terminal modem parameter value.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

In a sleep mode control method of an OFDMA / TDMA based mobile data network according to an embodiment of the present invention, the terminal AT and the AP use an OFDMA scheme. That is, it is classified into a downlink frame and an uplink frame according to the transmission direction of data between the terminal and the AP, and these frames have a time channel divided by a horizontal channel and a sub channel composed of orthogonal frequencies on the vertical axis. As such, the entire band consists of N subchannels, and each terminal transmits a frame using all N subchannels during the allotted time.

First, a sleep mode control method of an OFDMA / TDMA based mobile data network according to a first embodiment of the present invention will be described in detail with reference to FIG. 3.

3 is a diagram illustrating a sleep mode control method of an OFDMA / TDMA based mobile data network according to a first embodiment of the present invention.

In general, as shown in FIG. 3, the terminal AT operates in awake interval P _awake , sleep interval P _sleep , and Listening interval P _listening .

The UE operates in the normal mode in the normal period (n + 1 th frame to n + 2 th frame) (P _awake ), and when there is no data transmission or reception for a predetermined time, the UE sends a sleep_request (Sleep_REQ) message to the AP to switch to the sleep mode. It transmits (S300). At this time, the AP assigns a sleep mode CDMA code and a multicasting CID (caller-ID) to a terminal that switches to the sleep mode by associating the sleep mode CDMA code with the sleep mode multicasting group. Accordingly, the AP receiving the sleep_request (Sleep_REQ) message includes the allocated sleep mode CDMA code and the multicasting CID associated with the CDMA code in the sleep_response message and transmits it to the terminal (S310).

The UE that receives the sleep_response message operates in the sleep mode during the sleep period (n + 3 th frame to n + 6 th frame) (P _sleep ) and listens to the listening period (n + 7 th) to check whether there is data to be received from the AP. Switch to the listening mode of the frame (P _listening ).

After switching to the listening mode, the UE receives an M_RNG_RSP (Multicasting Ranging Response) message including the multicasting CID of the multicasting group to which the first downlink frame (n + 7th frame) belongs (S320). It is determined whether the terminal ID is included. At this time, if its own terminal ID is included, the terminal switches to the normal mode and prepares to receive data from the AP. On the other hand, if the terminal ID is not included in the received M_RNG_RSP message, the terminal calculates a _{sleep period} (n + 8 th frame ~ n + 12 th frame) (P _sleep ) and then switches from the listening mode to the sleep mode.

Meanwhile, when the M_RNG_RSP message is not received in the first downlink frame (n + 13th frame) of the _{listening period} (n + 3th frame to n + 14th frame) (P _listening ), the UE transmits a CDMA code to the AP. (S330). This step is the same as performing ranging in the terminal. That is, the terminal transmits the CDMA code to the AP (S330), and the AP receives the CDMA code, the transmission time and the parameter related to adjustment of the transmission strength that should be adjusted by the terminal modem based on the reception time and the reception strength of the CDMA code. In the multicasting CID of the multicasting group associated with the code, IDs of terminals currently waiting for data to be transmitted are included in the M_RNG_RSP message and multicasted to the terminals (S340). Upon receiving the M_RNG_RSP message from the AP, the UE, which has transmitted the CDMA code, adjusts modem-related parameters, checks whether its ID is included, and switches to normal mode, or otherwise enters sleep mode. In this step, the UE adjusts modem-related parameters by transmitting a CDMA code at least once within a periodic ranging time.

Meanwhile, since the CDMA code for the sleep mode is transmitted to the AP in a competitive manner, a collision may occur, but the performance analysis results of the 802.16e CDMA code-based random access method have a small probability of collision, and according to an embodiment of the present invention, Since the CDMA code is transmitted to the AP when the M_RNG_RSP message is not received, the collision probability is very small.

4 is a diagram illustrating a sleep mode control method of an OFDMA / TDMA based mobile data network in a terminal according to a second embodiment of the present invention.

As shown in FIG. 4, when there is no data transmission or reception for a predetermined time, the terminal transmits a Sleep Request message to the AP to switch from the normal mode to the sleep mode (S400), and receives a Sleep Response message from the AP (S402). .

The terminal detects and stores its sleep mode CDMA code and the multicasting CID of the multicasting group from the received Sleep Response message (S404). Thereafter, the terminal determines a sleep period and sets a sleep timer (S406).

The UE operates in the sleep mode during the sleep period and when the sleep time expires (S408), the terminal switches to the listening mode to check whether there is data to be received from the AP. The UE attempts to receive an M_RNG_RSP message from the downlink frame received for the first time after switching to the listening mode (S410). At this time, if the terminal does not receive the M_RNG_RSP message, it transmits the CDMA code to the AP and sets the sleep period to "0" (S412). Thereafter, when the UE which transmits the CDMA code to the AP receives the M_RNG_RSP message from the AP (S414), the UE adjusts a transmission time error and a transmission power (S416). If the M_RNG_RSP message includes its own terminal ID, it switches to the normal mode and receives data from the AP (S418-S424).

On the other hand, when the terminal that has switched to the listening mode after the sleep time expires receives the M_RNG_RSP message from the first received downlink frame (S410), it is determined whether the UE ID is included in the M_RNG_RSP message (S418). At this time, if the terminal ID is included in the M_RNG_RSP message, the terminal switches to the normal mode (S424). If the terminal ID is not included in the M_RNG_RSP message, the sleep interval is newly determined (S420). In operation S422, the terminal compares the determined sleep period with a preset periodic ranging period. At this time, if the sleep period is larger than the periodic ranging period, the terminal transmits a CDMA code and newly adjusts the current modem parameters (S412-S416). This has the same effect as newly adjusting modem parameter values by periodic ranging. On the other hand, if the sleep period is not greater than the periodic ranging period, the sleep period is repeated from the step of resetting.

5 is a diagram illustrating a sleep mode control method of an OFDMA / TDMA based mobile data network in an AP according to a third embodiment of the present invention.

As shown in FIG. 5, when the AP receives a sleep request message from the terminal (S500), the AP allocates a CDMA code for the sleep mode and a multicasting CID of the multicasting group (S510). The AP transmits the allocated sleep mode CDMA code and the multicasting CID to the terminal in the sleep response message (S520).

The AP manages the multicasting CID for the sleep mode (S560). When downlink data to be transmitted to the UE currently in the sleep mode arrives, the AP searches for the CID of the multicasting group to which the terminal belongs (S570). At this time, the AP stores the terminal ID in a buffer allocated to the multicasting CID (S580). The multicasting CID is included in the M_RNG_RSP message and multicasted. Therefore, upon receiving the M_RNG_RSP message, the terminal checks whether the message has its own terminal ID, and if the terminal determines that the message has its own terminal ID, the terminal switches to the normal mode.

However, when the terminal does not receive the M_RNG_RSP message from the base station, the terminal transmits a sleep mode CDMA code to the AP.

When the AP receives a sleep mode CDMA code from the UE (S530), the AP measures a transmission power and an arrival time from the sleep mode CDMA code, and determines a terminal modem parameter value according to the reception time and the reception power that the UE needs to adjust ( In operation S550, the terminal ID waiting for the downlink data to be transmitted in the multicasting group belonging to the CDMA code for the sleep mode is included in the M_RNG_RSP message and multicasted. At this time, the terminal transmits the CDMA code for the sleep mode at least once in the periodic ranging period for adjusting the transmission power according to the movement of the terminal and the data transmission time according to the distance between the AP. In this step, the AP can greatly reduce the complexity of the AP by transmitting the M_RNG_RSP message when receiving the CDMA code from the terminal without calculating the sleep time or the listening time of each terminal.

The above embodiments are intended to illustrate the present invention, the scope of the present invention is not limited to the embodiments, it can be modified or modified by those skilled in the art within the scope of the invention defined by the appended claims. .

According to the present invention, by integrating the sleep mode control and periodic ranging in a state where the terminal is switched to the sleep mode, when the terminal switches to the normal mode immediately without a separate periodic ranging procedure for adjustment of the modem parameters The state in which data can be transmitted and received can be maintained. In addition, when each terminal controls the sleep mode time and receives the CDMA code for the sleep mode from the terminal, the AP belongs to a terminal belonging to the multicasting group associated with the CDMA code including terminal IDs currently waiting for data to be transmitted in downlink and transmitted through the AP. The complexity can be greatly reduced and the lossless data transmission can be guaranteed.

1 is a diagram illustrating a sleep mode control method in the conventional OFDMA / TDMA 802.16e.

2 illustrates a periodic ranging procedure in the conventional OFDMA / TDMA 802.16e.

3 is a diagram illustrating a sleep mode control method of an OFDMA / TDMA based mobile data network according to a first embodiment of the present invention.

4 is a diagram illustrating a sleep mode control method in a terminal according to a second embodiment of the present invention.

5 is a diagram illustrating a sleep mode control method in an AP according to a third embodiment of the present invention.

Claims (13)

A sleep mode control method of a terminal wirelessly connected to a base station in an orthogonal frequency division multiplexing access / time division multiple access (OFDMA / TDMA) based mobile data network, a) requesting the base station to switch to sleep mode; b) receiving a response according to the request, wherein the response includes a code division multiple access (CDMA) code for sleep mode and a multicasting caller-ID (CID) for sleep mode; c) when the sleep mode is completed, transmitting the sleep mode CDMA code to the base station based on whether the sleep mode multicasting CID to which the sleep mode belongs is received from the base station; And d) receiving a response according to CDMA code transmission for sleep mode from the base station after step c) and performing ranging based on the received response; Sleep mode control method of OFDMA / TDMA based mobile data network comprising a. The method of claim 1, The sleep mode control method of the OFDMA / TDMA-based mobile data network to the CDMA code for the sleep mode in step c) is transmitted to the base station when the multicasting CID to which it belongs in step c) is not received. The method of claim 1, wherein d) d-1) receiving a multicasting ranging response message according to CDMA code transmission for sleep mode from step c); And d-2) adjusting a modem parameter value based on the multicasting ranging response message Sleep mode control method of OFDMA / TDMA based mobile data network comprising a. The method of claim 1, wherein b), Detecting and storing the sleep mode CDMA code and the sleep mode multicasting CID from a response according to the request for switching to the sleep mode; Determining a sleep interval for switching to the sleep mode and setting a sleep time; And Operating in a sleep mode during the set sleep time in the determined sleep period; Sleep mode control method of OFDMA / TDMA based mobile data network comprising a. The method of claim 1, When the multicasting CID for the sleep mode is received in step c), e) determining whether an ID is included in the multicasting CID for the sleep mode; And f) re-determining a sleep interval if the ID is not included in the multicasting CID for the sleep mode in step e) and comparing the re-determined sleep interval with a preset periodic ranging interval; Sleep mode control method of OFDMA / TDMA-based mobile data network further comprising. The method of claim 5, And in step f), if the sleep period is larger than the periodic ranging period, performing step d). The method of claim 5, And in step e), when the multicasting CID for the sleep mode includes its ID, operating in the normal mode of the OFDMA / TDMA based mobile data network. The method according to any one of claims 1 to 7, In step d), the sleep mode control method of the OFDMA / TDMA-based mobile data network to be performed at least once within the periodic ranging interval. A method for controlling a sleep mode of a terminal in a base station wirelessly connected to the terminal in an orthogonal frequency division multiplexing access / time division multiple access (OFDMA / TDMA) based mobile data network, a) allocating a code division multiple access (CDMA) code for a sleep mode and a multicasting caller-ID (CID) for a sleep mode to the terminal; b) upon receipt of a request to switch to sleep mode from the terminal, transmitting a response according to the request, wherein the response includes the assigned CDMA code for sleep mode and multicasting CID for sleep mode; ; c) searching for the multicasting CID to which the terminal belongs when the downlink data to be transmitted to the terminal currently in the sleep mode arrives; And d) transmitting the searched multicasting CID together with the downlink data to the terminal; Sleep mode control method of OFDMA / TDMA based mobile data network comprising a. The method of claim 9, If the terminal does not receive the multicasting CID to which it belongs in step d), Receiving a CDMA code for a sleep mode transmitted from the terminal; Determining a terminal modem parameter value based on the received CDMA code; And Transmitting, together with the downlink data, a terminal ID of the determined terminal modem parameter value and a downlink data currently to be transmitted in a multicasting CID belonging to the CDMA code for the sleep mode. Sleep mode control method of OFDMA / TDMA-based mobile data network further comprising. The method of claim 10, And c) storing the corresponding terminal ID in an allocated buffer of the searched multicasting CID in step c). The method according to any one of claims 9 to 11, And transmitting the CDMA code for the sleep mode from the terminal on the basis of whether the terminal receives the multicasting CID in step c). The method according to any one of claims 9 to 11, The sleep mode CDMA code is transmitted from the terminal at least once within a periodic ranging period for adjusting the terminal modem parameter value.