KR20060061051A - Method and system for providing quality of service in orthogonal frequency division multiple access wireless communication system - Google Patents

Abstract

The present invention includes a mobile subscriber station and an active base station in which the mobile subscriber station is currently being serviced. The present invention includes the active base station in a DCD message that periodically transmits information about QoS, and transmits it. Determines whether to reflect the QoS parameter set information by changing the configuration change count value included in the DCD message.

Therefore, by periodically transmitting QoS policy or parameter set information through a DCD message, it is possible to quickly apply information about QoS to the subscriber station without adding an individual message.

QoS, DCD, IEEE 802.16d / e

Description

METHOD AND SYSTEM FOR BROADCASTING QUALITY OF SERVICE IN WIRELESS COMMUNICATION SYSTEM USING OFDMA}             

1 is a diagram schematically illustrating a structure of a broadband wireless access communication system using a conventional OFDM / OFDMA scheme;

2 is a flowchart illustrating a process of receiving a downlink channel descriptor message from a subscriber station according to an embodiment of the present invention;

3 is a flowchart illustrating a quality of service (QoS) parameter information processing performed between a base station and a subscriber station according to an embodiment of the present invention.

The present invention relates to a method and system for providing a quality of service in a wireless communication system, and more particularly, to a method and system for providing and receiving a quality of service in a wireless communication system of orthogonal frequency multiple access.                         

Typically, a typical mobile communication system is a mobile communication system using a cellular communication scheme. Such a mobile communication system uses a multiple access scheme to simultaneously communicate with multiple users. As such, the multiple access method used in the mobile communication system includes a time division multiple access (TDMA) method and a code division multiple access (CDMA) method. It is typically used. The code division multiple access system has been developed in a form capable of transmitting high-speed packet data in a system mainly providing voice communication according to the rapid development of technology.

However, in the code division multiple access scheme, it is difficult to transmit more multimedia data while reaching the usage limit of the resource code. Accordingly, there is a demand for a multiple access method that can distinguish more users and transmit more data to each divided user. A multiple access scheme that is emerging to accommodate such a request is an Orthogonal Frequency Division Multiple Access (hereinafter, referred to as "OFDMA") scheme. The orthogonal frequency division multiple access method is a method of classifying users using subchannels maintaining a plurality of orthogonalities and transmitting data through them.

As described above, a cellular system using an OFDMA scheme has been proposed to transmit high-speed data in a cellular system. The OFDMA method has been researched and tried to provide high-speed wireless Internet service at the Institute of Electrical and Electronics Engineers (IEEE) 802.16d standardization conference. The 802.16 system is a system for supporting high-speed services beyond the speed provided by the third generation (3G) mobile communication system, and as described above, in addition to the various physical layer technologies used in the third generation mobile communication system, orthogonal High-speed services are implemented using transmission methods such as Frequency Division Multiplexing, multiple input / output ("MIMO") antenna methods, and advanced antenna techniques such as smart antennas.

Currently, the 3rd generation communication system generally supports a transmission rate of about 384 Kbps in an outdoor channel environment having a relatively poor channel environment, and a transmission rate of up to 2 Mbps even in an indoor channel environment having a relatively good channel environment. Meanwhile, a wireless local area network (LAN) system and a wireless metropolitan area network (MAN) system are generally 20Mbps ~ 20Mbps. It supports a transfer rate of 50Mbps. Therefore, in the current 4th generation (4G) communication system, a new communication system is developed in the form of guaranteeing mobility and QoS in a wireless LAN system and a wireless MAN system that guarantee a relatively high transmission speed, and to be provided in the 4G communication system. Researches to support high speed services are being actively conducted.

However, the wireless MAN system is suitable for supporting high-speed communication services because of its wide coverage and high-speed transmission, but does not consider the mobility of the user, that is, the subscriber station (SS). Since this is not a system, handover due to the fast movement of the subscriber station is not considered at all. In addition, the communication system considered in IEEE 802.16a is a system for performing a ranging operation between a subscriber station and a base station (BS). Next, a communication system structure considered in the IEEE 802.16a according to the prior art will be described with reference to FIG. 1.

1 is a diagram schematically illustrating a structure of a broadband wireless access communication system using a conventional orthogonal frequency division multiplexing / orthogonal frequency division multiple access scheme, and particularly a structure of an IEEE 802.16a communication system. .

Before explaining FIG. 1, the wireless MAN system is a broadband wireless access (BWA) communication system, which has a wider service area and supports a higher transmission speed than the wireless LAN system. In order to support a broadband transmission network to a physical channel of the wireless MAN system, an orthogonal frequency division multiple access (OFDM) scheme and an orthogonal frequency division multiple access (OFDMA) scheme are applied to a system that supports the IEEE 802.16a communication system. to be. The IEEE 802.16a communication system is a broadband wireless access communication system using an OFDM / OFDMA scheme. Since the IEEE 802.16a communication system applies the OFDM / OFDMA scheme to the wireless MAN system, high-speed data transmission is possible by transmitting a physical channel signal using a plurality of sub-carriers. In addition, the IEEE 802.16e communication system is a system that considers the mobility of a subscriber station in the IEEE 802.16a communication system.                         

The IEEE 802.d / e standard describes an air interface for point-to-multiplex bandwidth that provides multiple services in a broadband wireless network, and the frequency band of the application service (10-66 Ghz or 11 Ghz frequency). Band transmission method is used. Currently developed broadband wireless system uses TDD (Time Division Duplex) OFDMA transmission technology that provides portable Internet service in 2 ~ 6GHz frequency band. The system transmits high speed data of up to 30 to 50 Mbps per sector, can cover a wider range (1km / urban, 5km / rural) and provides mobility (60km / hour) compared to conventional wireless LAN systems. .

As a result, both the IEEE 802.16a communication system and the IEEE 802.16e communication system are broadband wireless access communication systems using the OFDM / OFDMA scheme. For convenience of description, the IEEE 802.16a communication system will be described as an example.

The OFDMA transmission scheme provides each user with a portion of a subcarrier (Sub carrier) available for transmitting high-speed data to multiple users to realize multiple access. In this case, more efficient high-speed data can be provided by changing the number of subcarriers allocated according to a transmission rate required by each user. OFDMA ensures orthogonality between users by eliminating intra-cell interference by assigning different subcarriers to each user. Therefore, it is possible to transmit data to a large number of users at a specific time, thereby increasing system capacity.

Referring to FIG. 1, the IEEE 802.16a communication system has a single cell structure, and a plurality of subscriber stations 110, 120 managed by the base station 100 and the base station 100, It consists of 130. Signal transmission and reception between the base station 100 and the subscriber stations (110, 120, 130) is performed using the OFDM / OFDMA method.

In a conventional broadband wireless network environment using the OFDMA transmission scheme, each terminal is provided with specific service flows.

The service flow provides a medium access for providing a unidirectional transport of packets for one of an uplink packet transmitted by a subscriber station (SS) or a downlink packet transmitted by a base station. Medium Access Control (hereinafter referred to as "MAC")-layer transport service.

The service flow is defined by a set of quality of service (hereinafter referred to as "QoS") parameters, such as latency, jitter of delay, and throughput assurance. Is characterized.

In order to standardize the operation between the subscriber station and the base station, the attributes include details of how the subscriber station requests uplink (UP-Link) resources and the type required by the base station uplink scheduler. The set of QoS parameters required for the service flow provided at this time is provided by the service provider.

The mechanism for providing QoS is to associate packets passing through the MAC layer interface to the service flow. The subscriber station and the base station provide the QoS based on a set of QoS parameters defined for the corresponding service flow.                         

The purpose of the QoS key points defined here is to define the transmission order and scheduling on the wireless connection.

The method of setting such defined QoS parameter set information is currently being discussed, and various methods are still proposed as an issue. In the currently proposed method, QoS parameter set information is determined for each service provider separately, and after the QoS parameter set information is previously set in the subscriber station, the service is provided using the QoS information.

The following problems exist in the existing technology in which a QoS parameter set necessary for a service provided by a service provider to a user is previously set in the subscriber station.

First, if a QoS policy, which has not been determined in advance, is determined after the setting of the subscriber station, it is not easy to notify the subscriber station about it, so that proper service provision is not guaranteed.

Secondly, if a new QoS parameter set is added after the QoS parameter set provided by the initial service provider, notification to the subscriber station is not appropriate, and thus immediate provision of the service is difficult.

Accordingly, an object of the present invention is to provide a method and system for providing an immediate service by directly reflecting information on a new service and providing a smoother service to a service user in an orthogonal frequency division multiple access wireless communication system.

Another object of the present invention is to provide a method and system for providing a subscriber station with a QoS parameter set provided by a service provider in a wireless communication system using an orthogonal frequency division multiple access scheme.

In accordance with an aspect of the present invention, a method for providing quality of service at a mobile subscriber station and a base station that is currently providing a service to the mobile subscriber station, wherein the base station includes new QoS parameter set information. Changing the configuration change count value of the downlink channel descriptive message, which is periodically transmitted, setting and adding the new QoS parameter set information added to the downlink channel descriptive message; The subscriber station confirms the presence or absence of the changed QoS parameter information by checking the configuration change count value included in the received downlink channel descriptive message, and if the changed QoS parameter exists, the subscriber station receives its QoS parameter information. Link Channel Descriptive Message It involves additional changes to the QoS parameter set information.

A system of the present invention for achieving the above objects is a new QoS in a mobile subscriber station of a wireless communication system and a system for providing quality of service (QoS) information at a base station providing a service to the mobile subscriber station. When the parameter set information is set and the base station for changing the configuration change count value of the downlink channel descriptive message to be transmitted periodically, and newly set and added the QoS parameter set information added to the downlink channel descriptive message; And receiving the downlink channel descriptive message to check whether the configuration change count value has changed, and reflecting the changed QoS parameter set information based on the QoS parameter set information when the configuration change count value has changed. Said mobile subscriber station It includes.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In a broadband wireless communication system using an OFDMA scheme, a subscriber station must acquire down-link parameters for communication with a base station and search for a serviceable branch station. First, the process of synchronizing the base station and the subscriber station to perform communication with each other must be preceded, which is possible by the subscriber station receiving a DL-MAP (Down Link-MAP) message transmitted by the base station.

In addition, for acquiring downlink parameters and searching for a base station, the base station periodically includes a downlink channel profile (DownLink Channel Descriptor) (hereinafter referred to as "DCD") to all subscriber stations located in the corresponding jurisdiction. Create and send messages.                     

The DCD message is sent by the base station periodically to define the characteristics of the downlink physical channel. The DCD message is broadcasted by the base station at regular intervals (DCD Interval).

If the subscriber station does not receive a valid DCD message, it cannot perform a procedure for receiving a service provided by the base station. Therefore, all subscriber stations should always receive the DCD message from the base station within the relevant jurisdiction.

Table 1 below shows information elements included in a DCD message provided by the base station to provide a service to the subscriber station according to an exemplary embodiment of the present invention (hereinafter referred to as "IE").

In the present invention, the base station transmits information on a more efficient QoS parameter set to the subscriber station by using the IE as shown in Table 1.

Syntax Size Notes DCD Message Format () { Management Message Type = 1 Downlink channel ID Configuration Change Count TLV Encoded information for the overrall channel variable  TLV Being PHY Specific Section { for (i = 1; I <= n; i ++) {  1 to n each downlink burst  Downlink_Burst_Profile profile physical layer properties }   } TLV Encoded information for QoS parameter set variable  TLV encoding  }

As shown in Table 1, the DCD message includes a plurality of IEs, that is, a management message type indicating a type of a transmitted message, a downlink channel ID indicating a downlink channel ID, and a configuration. A configuration change count value indicating a number of changes, a TLV encoded information for the overall channel indicating other information about a channel, a being PHY specific section value characteristic of a burst profile physical layer of each downlink, and the present invention. TLV Encoded information for QoS parameter set information indicating QoS parameter set information added according to the UE.

In an embodiment of the present invention, the base station broadcasts the DCD message at a predetermined periodic interval (DCD Interval). At this time, the base station periodically increases the configuration change count by one when the DCD message needs to be added or changed in addition to the QoS parameter set information included in the immediately transmitted DCD message.

The subscriber station compares the configuration change count value in the received DCD message with a configuration change count value of a DCD message transmitted before a previous DCD interval. If the configuration change count value is different from the configuration change count value of the previous received DCD message, the subscriber station recognizes that there is a change in the QoS information and transmits TLV Encoded information for QoS parameter set information in the IE of the newly received DCD message. As a basis, the parameter set information of the newly set service is reflected.

Hereinafter, a processing flow upon receiving a DCD message in the subscriber station according to an embodiment of the present invention will be described with reference to FIG. 2.

2 is a flowchart illustrating a process of receiving a DCD message at a subscriber station according to an embodiment of the present invention.

When the subscriber station receives the DL-MAP message from the base station in step 200, the subscriber station establishes MAC synchronization with the base station in step 202. When the subscriber station receives the DCD message from the base station in step 204, the UE searches for a configuration change count value in the received DCD message in step 206. In step 208, the subscriber station checks whether the retrieved configuration change count value is changed by comparing with a configuration change count value of a previously received DCD message. If the configuration change count value is 1 or more, it is recognized that the QoS parameter set information has been changed. In step 210, the subscriber station newly sets the added QoS parameter set information to communicate with the base station.

3 is a flowchart illustrating a quality of service (QoS) parameter information processing performed between a base station and a subscriber station according to an embodiment of the present invention.

First, in step 304, the base station 300 sets a MAC synchronization by transmitting a DL-MAP message to the subscriber station 302. When the subscriber station 302 and the base station 300 establishes the MAC synchronization, the base station 300 transmits a DCD message to the subscriber station 302 in step 306.

In step 308, the subscriber station 302 searches for a configuration change count value included in the received DCD message and checks whether the QoS has changed. In step 308, it is assumed that a configuration change count value of the first DCD message has not been changed. Thereafter, in step 310, the base station 300 transmits the next DCD message to the subscriber station 302 at a constant DCD interval. In step 312, the subscriber station 302 receiving the second DCD message searches for a configuration change count value of the second DCD message and checks whether the QoS has changed. In step 312, it is assumed that the configuration change count value of the second received DCD message is not changed.

If the base station 300 generates new QoS parameter set information after transmitting the second DCD message in step 314, before transmitting the third DCD message, the BS 300 transmits the information about the QoS parameter set information to the TLV Encoded information for QoS parameter set. Add. In addition, the base station 300 adds the newly reflected QoS information in addition to the newly changed QoS information before receiving the DCD message.

In step 316, the base station 300 transmits a DCD message reflecting the changed QoS information to the subscriber station 302. In step 318, the subscriber station 302 receiving the third DCD message searches for a configuration change count value of the DCD message and checks whether the QoS has changed.

In step 318, the subscriber station 302 recognizes that the configuration change count value of the third DCD message transmitted by the base station 300 is different from the configuration change count value of the previously received DCD message. .

In step 320, the subscriber station 302 recognizes that the QoS information has changed, and retrieves TLV Encoded information for QoS parameter set information indicating the added QoS parameter set information of the third received DCD message. 302 is reflected in the QoS parameter set information managed.

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 determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, the present invention provides a wideband wireless access communication system using an OFDM / OFDMA scheme, for example, a DCD message transmitted periodically by a base station periodically without setting a QoS parameter set to a subscriber station in an IEEE 802.16d / e communication system. It delivers the information about QoS provided by the service provider through the service, and adds the information to the DCD message when a change occurs later.

Therefore, by periodically transmitting QoS policy or parameter set information through a DCD message, it is possible to quickly apply information about QoS to the subscriber station without adding an individual message.

Claims (6)

A system for providing quality of service (QoS) information in a mobile subscriber station of a wireless communication system and a base station providing a service to the mobile subscriber station, When the new QoS parameter set information is set, change the configuration change count value of the downlink channel descriptive message transmitted periodically, The base station for newly setting and adding the QoS parameter set information added to the downlink channel decode message; Receiving the downlink channel descriptive message and checking whether the configuration change count value has changed, and reflecting the changed QoS parameter set information based on the QoS parameter set information when the configuration change count value has changed. Quality of service providing system in a wireless communication system of orthogonal frequency division multiple access method, characterized in that it comprises the mobile subscriber station. The method of claim 1, If the base station is different from the QoS information of the previously transmitted downlink channel descriptive message, the base station sets the configuration change count value to 1 or more. Tem. The method of claim 1, And the configuration change count value is 0 if the QoS information of the downlink channel descriptive message previously transmitted is zero. A method for providing a quality of service at a mobile subscriber station and a base station currently providing a service to the mobile subscriber station, Changing, by the base station, a configuration change count value of a downlink channel descriptive message periodically transmitted when new QoS parameter set information is set; Adding and newly setting the QoS parameter set information added to the downlink channel descriptive message; Checking, by the mobile subscriber station, whether there is a changed QoS parameter information by checking a configuration change count value included in the received downlink channel descriptive message; In case that the changed QoS parameter exists, the step of changing its QoS parameter information to the added QoS parameter set information of the received downlink channel descriptive message, characterized in that in the orthogonal frequency division multiple access wireless communication system How to Provide Quality of Service. The orthogonal frequency division multiple access scheme of claim 4, wherein the configuration change count value of the downlink channel descriptive message transmitted from the base station to the mobile subscriber station when the QoS change information is changed is one or more. How to Provide Quality of Service in Communications Systems. 5. The method of claim 4, wherein the mobile subscriber station replaces the added QoS parameter set information of the downlink channel descriptive message with new QoS parameter set information when the configuration change count value of the received downlink channel descriptive message is changed. Method of providing a quality of service in a wireless communication system of orthogonal frequency division multiple access method characterized in that set.

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