KR20060082129A - Device and method for assigning channel in wireless communication system - Google Patents

Abstract

The present invention relates to an apparatus and method for allocating a channel in a wireless communication system, and more particularly, to an apparatus and method for operating an H-ARQ ACK channel efficiently by a base station in a broadband wireless access system.

In a wireless communication system according to an embodiment of the present invention, a channel allocation method includes a base station and a mobile terminal receiving a packet data service from the base station. Receiving a frame, checking whether a change indication bit included in the frame includes a bit including a channel change, and when the change indication bit included in the frame includes a bit including a channel change, And using the newly allocated ACK allocation region.

Broadband Wireless Access System, H-ARQ MAP, H-ARQ ACK Channel, H-ARQ ACK Region Allocation IE

Description

Device and method for assigning channel in wireless communication system             

1 is a signal flow diagram between a mobile station and a base station in channel allocation in a wireless communication system according to an embodiment of the present invention;

2 is a control flowchart of channel allocation in a wireless communication system according to an embodiment of the present invention;

3 is a control flowchart of channel allocation in a wireless communication system according to another embodiment of the present invention;

4 is a block diagram of an uplink burst supporting H-ACK in accordance with the present invention;

The present invention relates to an apparatus and method for allocating channels in a wireless communication system, and more particularly, to an apparatus and method for allocating channels in a broadband wireless access system.                         

In general, a wireless communication system refers to a method of providing a user to perform communication regardless of a specific place using a terminal. Such a wireless communication system has been developed to accommodate a large number of users using various multiple access schemes. A typical method of the wireless communication system is a code division multiple access (CDMA) scheme. The code division multiple access scheme has been developed to process data at a relatively high speed, beginning with voice communication. As such, the development of code division multiple access is caused by the rapid development of technology with the demand for faster data transmission by users. The code division multiple access method has been commercialized due to the development of technology, and most standards of 3G mobile communication systems have been decided.

However, due to the limited resources used in the code division multiple access scheme, there is a problem that the limit for transmitting data at high speed is reached. Nevertheless, the transmission rate of data required by users continues to increase. Therefore, in the field of wireless communication, various researches and attempts have been made to transmit data at a higher speed.

As one of the above studies, an orthogonal frequency division multiple access (OFDMA) system using a broadband wireless communication technique has been studied. In the OFDMA scheme, a plurality of channels are formed using frequencies having orthogonality, and at least one or more channels are allocated to each user to transmit data. The IEEE 802.16 system is a representative standard protocol using such OFDMA scheme.

The IEEE 802.16 system can transmit a lot of data in a short time because the bandwidth of the data is wider than that of the wireless communication technology for voice service. In addition, the IEEE 802.16 system enables all users to share a channel and thus efficiently use the channel as compared to a wireless communication technology for voice service. That is, the IEEE 802.16 system uses a common channel for all users connected to the base station. In the system, a period in which each user uses a channel may be divided into an uplink frame and a downlink frame, and the use of every uplink frame and the downlink frame is allocated by the base station. Therefore, the base station of the system should inform the uplink and downlink access information so that each user can divide the channel for each frame. In the IEEE 802.16 system, access information is divided into uplink access information and downlink access information, and information on each channel is defined as a TLV (Type, Length, Value), and a downlink channel descriptor (DCD) and uplink channel descriptor (UCD) message is used. By including and transmitting to all users at regular intervals to inform the mobile terminal of the characteristic information on the channel.

In addition, the IEEE 802.16 system broadcasts uplink / downlink information for accessing a base station every frame so that a mobile station can access uplink / downlink information, which is an uplink map and a downlink map, respectively. ), Which together are called a map (MAP) message. In an IEEE 802.16 d / e system, H-ARQ MAP may be used to support a mobile terminal that can use a hybrid automatic repeat request (HARQ).

The IEEE 802.16 d / e system broadcasts uplink / downlink access information, and the mobile terminal receiving the message interprets the message and includes a compact uplink / downlink-map_information object (Compact UL / DL-MAP_IE). The burst period of the mobile terminal is allocated through the information, thereby allowing access to the uplink / downlink link of the base station.

The downlink map message may omit a ranging region allocation information entity (Ranging Region Allocation IE) when a ranging region that is a region to which a mobile terminal is to be allocated a channel does not change.

However, the mobile terminal operating in the sleep mode cannot receive the map message from the base station during the sleep mode, so that the mobile terminal is allocated before the sleep mode without receiving the changed ranging region information when the mobile terminal awakes. You will only have information about the ranging region. Therefore, a ranging channel must be allocated to every uplink map message for an effective ranging operation of a mobile station in a sleep mode. Then, the size of the uplink map message increases as the frame ranging channel information object is allocated.

Accordingly, an object of the present invention is to provide an apparatus and method for allocating an H-ARQ ACK region in a wireless communication system.

Another object of the present invention is to provide an apparatus and method for reducing the size of a map and reducing the transmission speed of a mobile terminal.

In a wireless communication system according to an embodiment of the present invention, a channel allocation method includes a base station and a mobile terminal receiving a packet data service from the base station. Receiving a frame, checking whether a change indication bit included in the frame includes a bit indicating a channel change, and if a change indication bit included in the frame includes a bit indicating a channel change, newly assigns And using the received ACK allocation region.

In addition, the method of allocating a channel in a wireless communication system according to another embodiment of the present invention provides a method for allocating a channel to a mobile terminal in a broadband wireless access system including a base station and a mobile terminal receiving packet data service from the base station. Receiving a frame from the base station; determining whether a UCD counter included in the received frame has changed; and using a newly allocated ACK allocation region when the UCD counter is changed. It is characterized by.

In addition, the apparatus for allocating a channel in a wireless communication system according to another embodiment of the present invention provides a channel allocating apparatus in a broadband wireless access system including a base station and a mobile terminal provided with a packet data service from the base station. A base station transmitting a frame including a change indication bit, and a mobile terminal receiving a frame from the base station and using a newly allocated ACK allocation region when the change indication bit included in the frame is not a "0" bit. It is characterized by.                         

In addition, the apparatus for allocating a channel in a wireless communication system according to another embodiment of the present invention provides a channel allocating apparatus in a broadband wireless access system including a base station and a mobile terminal provided with a packet data service from the base station. A base station transmitting a frame including a UCD counter change, and a mobile terminal receiving a frame from the base station and using a newly allocated ACK allocation region when the UCD counter change included in the frame exists. It features.

In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

Movement by the Present Invention The present invention described below is applied to an IEEE 802.16e system, and an embodiment of the present invention will be described for an efficient method for improving an H-ARQ ACK channel in the IEEE 802.16e.

In the related art, the size of the map of the uplink message increases as the frame ranging channel information is allocated. In the present invention, the control channel region is fixed so that it is not necessary to allocate the ranging region every frame. The present invention proposes two methods for efficiently allocating a hybrid automatic repeat request (HARQ) ACK region allocation information entity.

First embodiment

The first method for efficiently allocating an H-ARQ ACK region allocation information entity is to use a change indication bit. As a bit included in the UCD message transmitted from the base station, when the change indication bit is a "0" bit, an existing allocated ACK channel region is used. However, when the change indication bit is a "1" bit, the newly allocated ACK channel region is used.

In the present invention, an H-ARQ ACK region allocation information entity is used to define an uplink region required for an ACK channel of a mobile terminal supporting H-ARQ. Table 1 below shows the configuration of the H-ARQ ACK channel region information entity. The H-ARQ ACK region information entity includes a 4-bit Extended Downlink Interval Usage Code (DIUC) field, a 4-bit Length field, an 8-bit OFDMA Symbol Offset field, 6-bit subchannel offset field, 8-bit number OFDMA offset field, 6-bit number subchannel offset field, variable size padding bits It consists of a (Padding bits) field.                     

The subchannel of the ACK channel region can be divided into two half-subchannels.

The first half subchannel consists of odd tiles of the first, third, and fifth. Also, the second half subchannel consists of even tiles such as second, fourth, sixth, and so on. That is, by using one subchannel in half, the subchannels can be doubled.

In the present invention, as shown in FIG. 1, the mobile station supports H-ARQ and receives the H-ARQ downlink burst in the i-th frame in step 101. Then, in step 102, the mobile terminal should transmit an ACK signal to the base station using the half subchannel. At this time, an ACK is transmitted in an i + j th frame of the ACK channel region. In this case, the frame offset j is defined in the 'H-ARQ ACK Delay for DL Burst' field in the Uplink Channel Descriptor (UCD) message. The offset of the half subchannel of the ACK channel region is determined in the order of bursts supporting H-ARQ in the downlink map. For example, if a mobile terminal receives a burst supporting H-ARQ in an i-th frame and the burst is a burst supporting n-th H-ARQ, the mobile terminal receives an ACK channel of an i + j frame allocated by a base station. An ACK signal should be sent to the base station on the nth half subchannel of the region.

A method of fixedly allocating an H-ARQ ACK region using a change indication bit in the base station as described above will now be described with reference to FIG. 2.

First, in step 201, the mobile terminal receives a frame from the base station. In step 202, the mobile terminal checks whether the change indication bit of the received frame is "0". If the change indication bit of the received frame is not "0", as suggested by the present invention, the mobile station uses the newly allocated ACK channel region in step 203. However, if the change indication bit of the received frame is "0", the mobile terminal uses the previously assigned ACK channel region in step 204.

Second embodiment

The second way to solve the problem of H-ARQ ACK channel assignment is to use TLV for control channel assignment. As described above, since the mobile station operating in the sleep mode cannot receive the map message during the sleep period, the base station should transmit the ranging channel allocation information to the mobile station every frame. In the present invention, a general control region allocation information entity (General Control Region Allocation IE) is included in a UCD message to reduce the overhead of growing the map message. The mobile terminal can detect a change in the control channel using the UCD counter in the map message. Therefore, even if the control channel information is not transmitted from the base station every frame, when the mobile station receives the map message after changing from the sleep mode to the active mode, it detects the change of the control channel information. Thereafter, the mobile terminal enables normal operation after receiving the changed control channel information. Table 2 below defines TLVs to include the universal control region allocation information entity in a UCD message.

The composition of the universal control region allocation information object is shown in Table 3. The universal control region allocation information object includes a 2-bit usage field indicating the purpose of using the control information, a 7-bit subchannel offset field, an 8-bit number OFDMA offset field, And a 7-bit number subchannel offset (No. subchannel offset field) and a padding field. When the use of the control information is ranging, a 2-bit ranging method field indicating a ranging method is added.                     

Channel allocation method in a wireless communication system according to a second embodiment of the present invention will be described with reference to FIG.

First, the mobile terminal is in the sleep mode in step 301 and operates in the activation mode. Then, the mobile terminal receives the UCD message from the base station in step 302. In step 303, the mobile terminal determines whether there is a change of the UCD counter in the UCD message. If there is a change of the UCD counter in the UCD message, the mobile station receives the general control region allocation information entity proposed in the present invention in step 304. However, if there is no change of the UCD counter in the UCD message, the mobile station uses the previously allocated ACk channel region in step 305.

The first and second embodiments have described the contents of the H-ARQ ACK channel for downlink traffic of the base station. However, when the mobile station supports uplink H-ARQ traffic, the base station must also send an H-ARQ ACK to the mobile station. In the present invention, the base station has defined the H-ARQ ACK IE for the H-ARQ ACK for transmission to the mobile terminal. The H-ARQ ACK IE consists of a 4-bit Extended DIUC field, a 4-bit Length field, and a variable-size Bitmap field, as shown in Table 4 below. . The bitmap contains H-ARQ ACK information for an uplink burst that supports H-ARQ. That is, when the ACK information is made into bits as many as the number of bursts in order to send an H-ARQ ACK for the burst transmitted by the base station, the mobile station can check its bitmap and confirm whether the base station has normally received the burst. Therefore, the size of the bitmap is equal to or larger than the number of uplink bursts supporting H-ARQ. This is shown in FIG. Suppose there is an uplink burst that supports eight H-ARQs. In this case, if the data of burst 3 and burst 5 of the burst received by the base station is abnormal and the rest is received normally, all terminals can see this bitmap if NACK is displayed for the burst 3 and burst 5. Of these, only the bit corresponding to itself is checked to determine whether to retransmit the burst.                     

The frame offset interval of the uplink bus and the H-ARQ ACK bitmap is specified in the 'H-ARQ_ACK_Delay_for UL Burst' field in the DCD message. For example, if the mobile terminal transmits an H-ARQ capable uplink burst in the i-th frame and the burst is the j-th burst of the map, the mobile terminal transmits the j-th bit of the bitmap in the (i + j) -th frame from the base station. You should be able to check.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention has the effect of reducing the size of the map and increasing the uplink transmission speed of the mobile terminal by using a method of using the change indication bit for H-ARQ ACK channel allocation.

The present invention has the effect of reducing the size of the map and increasing the uplink transmission speed of the mobile terminal by using a control channel allocation method for the H-ARQ ACK channel allocation.

The present invention also provides an H-ARQ ACK method of a base station for an uplink burst supporting H-ARQ.

Claims (7)

In the wireless communication system comprising a base station and a mobile terminal receiving a packet data service from the base station, the mobile terminal is a channel assignment method, Receiving a frame from the base station; Checking whether a change indication bit included in the frame includes a bit indicating a channel change; If the change indication bit included in the frame includes a bit indicating a channel change, using the newly allocated ACK allocation region. The method of claim 1, The frame comprises the H-ARQ ACK region allocation information entity for a mobile terminal that supports H-ARQ. The method of claim 1, If the change indication bit is a bit indicating a channel change, the change indication bit is indicated by a "0" bit. In the wireless communication system comprising a base station and a mobile terminal receiving a packet data service from the base station, the mobile terminal is a channel assignment method, Receiving a frame from the base station; Determining whether a UCD counter included in the received frame is changed; If the UCD counter is changed, using the newly allocated ACK allocation region. The method of claim 4, wherein Wherein the frame includes a universal control region allocation information entity for a mobile terminal that supports H-ARQ. An apparatus for allocating a channel in a wireless communication system including a base station and a mobile terminal receiving a packet data service from the base station, A base station transmitting a frame including a change indication bit to the mobile terminal; And a mobile terminal receiving a frame from the base station and using a newly allocated ACK allocation region when the change indication bit included in the frame is not a "0" bit. An apparatus for allocating a channel in a wireless communication system including a base station and a mobile terminal receiving a packet data service from the base station, A base station for transmitting a frame including the UCD counter change to the mobile terminal; And a mobile terminal receiving a frame from the base station and using a newly allocated ACK allocation region when there is a UCD counter change included in the frame.

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