KR100667696B1 - A method for preamble based bandwidth request in wireless internet system - Google Patents

Abstract

The present invention relates to a preamble-based bandwidth request method.

According to the present invention, in the portable Internet system requesting bandwidth using the preamble, the state of the mobile terminal can be adjusted according to the most recent environment, so that user data can be transmitted more efficiently. In addition, according to the present invention, when an attempt is made to request a bandwidth using a preamble, information for identifying a terminal from which the base station transmits the preamble, together with state control information for the terminal, as a temporary connection identifier next time with the corresponding terminal. Terminals should be distinguished when transmitting data.

 Preamble based, wireless internet, band request, random access attempt

Description

Preamble-based Bandwidth Request Method for Wireless Mobile Internet System {A METHOD FOR PREAMBLE BASED BANDWIDTH REQUEST IN WIRELESS INTERNET SYSTEM}

1 is a schematic diagram of a wireless portable Internet system.

2 is a diagram illustrating a connection setup process of a wireless portable Internet system.

3 is a diagram illustrating a conventional preamble-based bandwidth request method.

4 is a diagram illustrating a hierarchical structure of a wireless portable Internet system proposed by IEEE 802.16e.

5 is a diagram schematically illustrating a connection structure between a base station and a subscriber station in a wireless portable Internet system according to an embodiment of the present invention.

6 is a frame diagram illustrating a frame structure of a wireless portable Internet system according to an embodiment of the present invention.

7 is a diagram illustrating a preamble-based bandwidth request method according to a first embodiment of the present invention.

8 is a diagram illustrating a preamble-based bandwidth request method according to a second embodiment of the present invention.

The present invention relates to a bandwidth request method of a wireless Internet system, and more particularly, to a preamble-based bandwidth request method of a wireless portable Internet system proposed by the IEEE 802.16 standard group.

The wireless portable Internet is a next generation communication method that further supports mobility in a short range data communication method using a fixed access point such as a conventional wireless local area network (LAN). Various standards for the wireless portable Internet have been proposed. Currently, international standardization of the portable internet is being carried out around the IEEE 802.16 standardization group.

1 is a schematic diagram showing an outline of a wireless portable Internet system being promoted by the IEEE 802.16 group and the like.

The wireless portable Internet system basically includes a subscriber station 10, base stations 20 and 21 performing wireless communication with the subscriber station, routers 30 and 31 connected through the base station and a gateway, and an internet network.

In the wireless portable Internet system illustrated in FIG. 1, even when a subscriber station 10 (hereinafter, simply referred to as SS) moves from a cell managed by the base station 20 to a cell managed by the base station 21 To ensure that, data communication services are provided without interruption. That is, the wireless portable Internet system shown in FIG. 1 supports handover of the subscriber station 10 like a mobile communication service, and performs dynamic IP address allocation according to the movement of the subscriber station.

2 is a flowchart illustrating a connection setting process of a wireless portable Internet system.

When the subscriber station 10 enters the base station 20 (S1), the base station 10 first establishes downlink synchronization with the subscriber station (S2). If downlink synchronization is configured, the subscriber station acquires an uplink parameter S3.

After the subscriber station acquires an uplink parameter, a ranging procedure between the subscriber station and the base station is performed. In this case, ranging refers to adjusting and matching timing, power, and frequency information between a subscriber station and a base station. Initial ranging is performed initially, and then periodically ranging is performed periodically. Perform

When the ranging procedure is completed, negotiation with respect to the basic (service) provision capability for establishing a connection with the subscriber station and the base station. (S5) When the negotiation about the basic (service) provision capability is completed, the base station performs subscriber station authentication using a device identifier and certificate, such as a medium access control (MAC) address of the subscriber station (S6).

When authentication of the subscriber station is completed and the authority to use the wireless portable Internet is confirmed, the device address of the subscriber station is registered (S7), and an IP address is received from an IP address management system such as a dynamic host configuration protocol (DHCP) server. Provided to the subscriber station to perform an IP connection (S8). The subscriber station receiving the IP address performs connection establishment for data transmission. (S9)

On the other hand, the subscriber station may request a bandwidth from the base station may be divided into a contention-based bandwidth request method and a contention-based bandwidth request method.

Non-competitive bandwidth request methods include unicast polling and piggybacking, which are the same as the existing messaging-based bandwidth request. However, these methods are not efficient when there is not enough bandwidth. Has its drawbacks.

That is, when the bandwidth available to the terminal can be allocated in the uplink, such a unicast polling or piggyback method can be efficiently used. However, if the bandwidth available to the terminal is not allocated in the uplink, such a method cannot be used and a contention-based bandwidth request must be made.

Therefore, the portable Internet system proposed by the IEEE 802.16 standardization group uses a CDMA-based bandwidth request method, which is a kind of contention-based bandwidth request method.

In the portable Internet system proposed by the IEEE 802.16 standardization group, CDMA-based periodic ranging and bandwidth requests are transmitted in the same uplink domain. In this case, the bandwidth request is for the terminal to request the uplink bandwidth allocation to the base station, the periodic ranging request is used to periodically adjust the system to reflect the channel state. In addition, two ranging codes (or preambles, hereinafter, codes or preambles have the same meaning) used for bandwidth request and periodic ranging are uplink channel presenters (UCDs) transmitted by the base station to the terminal. Only identified by code usage groups that are identified or dynamically assigned through uplink channel descriptors.

3 is a diagram illustrating a bandwidth request method of a conventional portable Internet system.

Referring to FIG. 3, the terminal SS transmits a periodic ranging code to the base station after the periodic ranging timer expires (S41), and the base station BS transmits a ranging response message (RNG-RSP) including state control information. ) Is transmitted to the terminal. (S42) When the terminal receives the response to the periodic ranging from the base station, and adjusts the timing, power, frequency and the like based on the state control information transmitted by the base station. The periodic ranging process is repeated in units of a predetermined interval (T1, hereinafter, referred to as a 'cyclic ranging interval').

When the terminal wants to transmit uplink data (S44), the terminal transmits a bandwidth request code (BW Req Code) to the base station, (S45) the base station receiving the bandwidth request code transmits a bandwidth request message to the terminal Allocate resources that can be used. In this case, since the base station cannot distinguish from which mobile terminal the corresponding bandwidth request code (or preamble) is transmitted by the identifier of the mobile terminal, information for identifying the terminal transmitting the code (frame number, slot number, Subchannel number, code number, etc.) are allocated through CDMA_Allocation_IE of UL-MAP. Upon receiving this, the UE transmits a bandwidth request header (BW Req Hdr) and / or uplink data (UL Data), which are values of exact bandwidth required by the UE, in a bandwidth request message (S47).

According to the conventional method shown in FIG. 3, the adjustment of the timing, power, frequency, etc. for the channel state is performed only by periodic ranging, and no separate adjustment is performed at the time of bandwidth request. As a result, when the data is transmitted using the allocated bandwidth after transmitting the bandwidth request code, the data is transmitted without adjusting the adjustment information according to the state of the channel. Since the channel state does not change frequently in a fixed wireless environment, as shown in FIG. 3, it is sufficient to adjust the terminal according to the channel state only by periodic ranging repeated in predetermined intervals (T1). However, in the mobile environment, the channel state changes frequently compared to the fixed wireless environment. Therefore, when the method shown in FIG. 3 is used, an appropriate adaptive modulation and coding level (AMC level) reflecting the channel state is determined. There is a drawback that the transmission is difficult because it is not applicable. Moreover, when timing is not correct among state adjustment information, there exists a problem which acts as an interference to the data of a user using an adjacent subchannel.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the problems of the prior art as described above, and the present invention is to provide a bandwidth method using a preamble for quickly adapting to a channel environment.

Preamble-based bandwidth request method according to an aspect of the present invention for achieving the above object is

(a) receiving a bandwidth request code from a terminal;

(b) transmitting state control information according to a channel state to the terminal; And

(c) allocating an uplink resource for transmitting a bandwidth request message to the terminal.

On the other hand, the preamble-based bandwidth request method according to another aspect of the present invention

(a) receiving a periodic ranging code from a terminal;

(b) transmitting the state control information according to a channel state to the terminal through a ranging response message;

(c) receiving a bandwidth request code from the terminal;

(d) transmitting channel state information according to a channel state and information for distinguishing the terminal to a terminal through a ranging response message; And

(e) allocating an uplink resource for transmitting a bandwidth request message to the terminal.

Meanwhile, the preamble-based bandwidth request method according to another feature of the present invention

(a) receiving a periodic ranging code from a terminal;

(b) transmitting the state control information according to a channel state to the terminal through a ranging response message;

(c) receiving a bandwidth request code from the terminal;

(d) transmitting, via a ranging response message, a temporary connection identifier allocated to the terminal that has transmitted the condition control information according to a channel state and a bandwidth request code to the terminal; And

(e) allocating an uplink resource for transmitting a bandwidth request message to the terminal using the temporary connection identifier.

Meanwhile, the preamble-based bandwidth request method according to another feature of the present invention

(a) transmitting a bandwidth request code to a base station;

(b) receiving channel condition control information as a response to the bandwidth request code to the base station, and adjusting a state of the terminal based on the channel condition control information;

(c) receiving an uplink resource for transmitting a bandwidth request message from the base station; And

(d) performing modulation and channel coding based on channel state information received from the base station and transmitting uplink data through the bandwidth request message.

According to the present invention, the state of the mobile terminal is controlled according to the most recent environment in a wireless Internet system (or a mobile communication system) requesting bandwidth using a preamble, thereby enabling a more efficient user. Enable the transfer of data.

In addition, since the present invention cannot distinguish which mobile station the preamble is transmitted from when a bandwidth request is attempted using the preamble, a temporary connection identifier for identifying a terminal that transmits a specific preamble together with state control information By providing Identifier: temporary CID), it can be used as an identifier for identifying the terminal when transmitting data with the corresponding terminal.

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.

Hereinafter, a bandwidth request method applicable to the portable Internet system proposed by IEEE 802.16e will be described as an example, but the present invention is not necessarily limited thereto.

4 is a hierarchical diagram showing the hierarchical structure of the wireless portable Internet system of IEEE 802.16e.

As shown in FIG. 4, the hierarchical structure of the IEEE 802.16e wireless portable Internet system is largely divided into a physical layer (L10) and a media access control (hereinafter referred to as MAC) layer (L21, L22, L23). do.

The physical layer L10 is responsible for a wireless communication function performed in a normal physical layer such as modulation and demodulation and coding.

As illustrated in FIG. 4, according to IEEE 802.16e, like a wired Internet system, the MAC layer does not have a MAC layer subdivided into its functions, and performs various functions in one MAC layer. Looking at the sub-layers by their function, the MAC layer according to an embodiment of the present invention includes a privacy sub-layer L21, a MAC common sub-layer L22, and a service specific convergence sub-layer L23.

The service specific convergence sublayer L23 is responsible for payload header suppression and quality of service (QoS) mapping functions in continuous data communication. The MAC common part sublayer (L22) is an integral part of the MAC layer and is responsible for system access, bandwidth allocation, connection establishment and maintenance, and QoS management. The privacy sublayer L21 performs device authentication, security key exchange, and encryption functions.

5 is a schematic diagram illustrating a connection structure between a base station and a subscriber station device in a wireless portable Internet system according to an embodiment of the present invention.

The MAC layer of the subscriber station SS and the MAC layer of the base station BS have a connection relationship with each other. The term " connection C1 " used in the embodiment of the present invention refers to a logical connection rather than a physical connection. The SS and the BS are used to transmit traffic of one service flow. ) Is defined as a mapping relationship between MAC peers.

Therefore, the parameter or message defined on the connection C1 defines a function between MAC sibling layers, and in reality, the parameter or message is processed and framed and transmitted through the physical layer. It will perform a function corresponding to a parameter or a message.

The MAC message transmitted through this connection (C1) is basically a Connection Identifier (hereinafter referred to as CID) which is a MAC layer address identifying the connection; A MAP that defines a symbol offset of a burst time-divided by the subscriber station on the downlink / uplink link, a subchannel offset, a symbol number of allocated resources, and a number of subchannels; Channel Descriptors (hereinafter, referred to as DCD and UCD, respectively) that describe characteristics of the physical layer according to the downlink / uplink characteristics, and the like. In addition, the MAC message includes various messages for performing a request (REQ), response (RSP), and acknowledgment (ACK) for various operations.

6 is a frame diagram illustrating a frame structure of a wireless portable Internet system according to an embodiment of the present invention.

As shown in FIG. 6, the frame is divided into a downlink frame F1 and an uplink frame F2 according to a transmission direction. The vertical axis of the frame is a subchannel composed of orthogonal frequencies, and the horizontal axis represents a time-divisional time axis.

The downlink frame F1 includes a preamble, a downlink MAP, an uplink MAP, and a plurality of downlink bursts. The downlink bursts are not classified channels or resources by users, but are classified by transmission levels having the same modulation scheme or channel encoding. The downlink MAP is provided with offset information, modulation scheme information, and coding information corresponding to a plurality of users using the same modulation scheme and channel coding to perform resource allocation for the user. Therefore, the MAP has the characteristics of a broadcast channel and requires high robustness.

Meanwhile, in the case of uplink frame F2, transmission is performed for each user, and the uplink burst includes user-specific information.

7 is a diagram illustrating an example of a preamble-based bandwidth request method according to a first embodiment of the present invention.

As shown in FIG. 7, the terminal SS transmits a periodic ranging code to the base station after the periodic ranging timer expires (S100), and the base station BS responds to the periodic ranging (RNG-RSP). ) Is transmitted to the terminal. When the terminal receives a response to the periodic ranging from the base station, the terminal adjusts timing, power, frequency, and the like based on the response message. (S120)

When the terminal wants to transmit the uplink data (S130), the terminal transmits a bandwidth request code (BW Req Code) to the base station. As shown in FIG. 7, according to an embodiment of the present invention, the base station that receives the bandwidth request code sends a ranging response message (RNG-RSP) including state control information as in the case of a periodic ranging code request. Send to the terminal. In operation S150, the terminal adjusts timing, power, frequency, and the like based on the ranging response message. In this case, since the base station cannot distinguish from which mobile terminal a corresponding bandwidth request code (or preamble) is transmitted by an identifier of the mobile terminal, information for identifying a terminal transmitting the corresponding code (frame number, slot number, Subchannel number, code number, etc.) in the ranging response message.

The base station allocates a resource for transmitting the bandwidth request message to the corresponding terminal after a predetermined time after the ranging response message is transmitted. In this case, the base station allocates the corresponding resource through the CDMA_Allocation_IE of the UL-MAP by using the information for identifying the terminal that has transmitted the bandwidth request code.

Upon receipt of this, the UE transmits a header header (BW Req Hdr) and / or UL data (UL Data), which are values of the exact bandwidth required by the UE, in a bandwidth request message (S180). In this case, according to the embodiment of the present invention, since timing, power, and frequency are adjusted based on the ranging response message for the bandwidth request code, uplink data is performed by performing modulation and channel encoding appropriate to recent state information. Can transmit

According to the first embodiment of the present invention shown in Figure 7, since the adjustment of the timing, power, frequency, etc. for the channel state is performed not only at the periodic ranging request but also at the bandwidth request, after transmitting the bandwidth request code. When data is transmitted using the allocated bandwidth, data can be transmitted by adjusting the adjustment information according to the state of the channel.

That is, according to the first embodiment of the present invention, since the terminal is adjusted according to the channel state at the time of bandwidth request as well as the periodic ranging, the periodic ranging period compared to the conventional periodic ranging period T1 shown in FIG. (T2) can be reduced. Therefore, even when the mobile station transmits data even in a mobile environment where the channel state changes frequently, an appropriate adaptive modulation and coding level (AMC level) reflecting the radio channel state can be applied to efficiently transmit data. Can transmit In addition, since the data transmission timing of each terminal can be matched, it is possible to reduce the problem of acting as interference to the data of the user using the adjacent subchannel.

8 is a diagram illustrating a preamble-based bandwidth request method according to a second embodiment of the present invention.

In FIG. 8, the same reference numerals are used to perform the same and similar functions as those described in FIG. 7, and overlapping descriptions will be omitted.

 Referring to FIG. 8, as a response to the bandwidth request using the preamble, the base station transmits state control information and a temporary CID through a ranging response message. Unlike the first embodiment shown in FIG. 7, the base station allocates an uplink resource for transmitting a bandwidth request message to a terminal identified as a temporary CID. That is, the base station allocates the corresponding resource through the UL_MAP_IE message by using the temporary identifier.

According to the first embodiment of the present invention illustrated in FIG. 7, information for distinguishing a terminal transmitting a code (preamble) when transmitting uplink control information and when allocating an uplink resource for transmitting a bandwidth request message is provided. On the other hand, according to the second embodiment of the present invention shown in FIG. 8, in order to prevent such information from being duplicated when the status control information is transmitted and when the resource is allocated, the temporary CID is previously set. Allocating an uplink resource for transmitting the bandwidth request message by using the temporary CID has the advantage of reducing the waste of resources.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various other modifications and changes are possible.

For example, in the embodiment of the present invention, the wireless portable Internet system of IEEE 802.16e has been described as an example, but can be applied to other wireless Internet system standards. In addition, the present invention is of course applicable not only to wireless portable systems but also to other mobile communication systems in which mobility is supported.

As described above, the present invention enables an efficient bandwidth request attempt that can be adapted to a channel environment in a wireless Internet system that attempts to request a bandwidth using a preamble.

In addition, according to the present invention, there is an effect of reducing the overhead by not overlapping the information for identifying the terminal that transmitted the preamble.

Claims (17)

In the preamble-based bandwidth request method in a wireless portable Internet system, (a) receiving a bandwidth request code from a terminal; (b) transmitting state control information according to a channel state to the terminal; And (c) allocating an uplink resource for transmitting a bandwidth request message to the terminal. The method of claim 1, In the step (b), the preamble-based bandwidth request method, characterized in that for transmitting the status control information using a response message. The method of claim 2, In the step (b), the bandwidth request method based on the preamble, characterized in that for transmitting the information to identify the terminal that transmitted the bandwidth request code in the response message. The method of claim 3, The information for identifying the terminal is a preamble-based bandwidth request method, characterized in that any one or more of a frame number, slot number, subchannel number, code number. The method of claim 4, wherein Preamble-based bandwidth request method, characterized in that in step (c) by using the information for identifying the terminal to allocate an uplink resource for transmitting a bandwidth request message to the terminal. The method according to any one of claims 2 to 5, And the response message is a ranging response message. The method of claim 2, In the step (b), the preamble-based bandwidth request method, characterized in that for assigning a temporary connection identifier to the terminal that transmitted the bandwidth request code, and transmitted through the response message. The method of claim 7, wherein In the step (c), using the temporary connection identifier transmitted in the step (b), preamble-based bandwidth request method, characterized in that for allocating an uplink resource for transmitting a bandwidth request message to the terminal. In the preamble-based bandwidth request method in a wireless portable Internet system, (a) receiving a periodic ranging code from a terminal; (b) transmitting the state control information according to a channel state to the terminal through a ranging response message; (c) receiving a bandwidth request code from the terminal; (d) transmitting channel state information according to a channel state and information for distinguishing the terminal to a terminal through a ranging response message; And (e) preamble-based bandwidth request method comprising allocating an uplink resource for transmitting a bandwidth request message to the terminal. The method of claim 9, The information for identifying the terminal is a preamble-based bandwidth request method, characterized in that any one or more of a frame number, slot number, subchannel number, code number. The method of claim 9, Preamble-based bandwidth request method, characterized in that in the step (e) using the information for identifying the terminal to allocate the uplink resource for transmitting a bandwidth request message to the terminal. The method of claim 11, The uplink resource is a preamble-based bandwidth request method, characterized in that allocated through the CDMA_Allocation_IE of the uplink map. In the preamble-based bandwidth request method in a wireless portable Internet system, (a) receiving a periodic ranging code from a terminal; (b) transmitting the state control information according to a channel state to the terminal through a ranging response message; (c) receiving a bandwidth request code from the terminal; (d) transmitting, via a ranging response message, a temporary connection identifier allocated to the terminal that has transmitted the condition control information according to a channel state and a bandwidth request code to the terminal; And (e) allocating an uplink resource for transmitting a bandwidth request message to the terminal using the temporary connection identifier. In the preamble-based bandwidth request method in a wireless portable Internet system, (a) transmitting a bandwidth request code to a base station; (b) receiving channel condition control information as a response to the bandwidth request code to the base station, and adjusting a state of the terminal based on the channel condition control information; (c) receiving an uplink resource for transmitting a bandwidth request message from the base station; And (d) performing modulation and channel coding based on channel state information received from a base station and transmitting uplink data through the bandwidth request message. The method of claim 14, In the step (b), the preamble-based bandwidth request method, characterized in that receiving the temporary connection identifier assigned to itself from the base station with the state control information. The method of claim 15, In step (c), the preamble-based bandwidth request method according to claim 1, wherein the uplink resource is allocated using the temporary connection identifier received in step (b). The method according to any one of claims 14 to 16, In step (b), the state adjustment of the terminal is a preamble-based bandwidth request method, characterized in that any one or more of the timing, power and frequency.

Images