RU2494575C2 - Method for bandwidth requesting in wireless communication system - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method of requesting bandwidth in a wireless communication system includes: transmitting a bandwidth request indicator and a bandwidth request message over a bandwidth request channel; receiving an uplink enable message indicating an uplink radio resource in response to the bandwidth request indicator and the bandwidth request message; and transmitting uplink data after receiving the uplink enable message, wherein the uplink enable message includes information on the type of uplink enable message.

EFFECT: bandwidth request can be carried out fast and efficiently.

14 cl, 10 dwg, 6 tbl

Description

FIELD OF THE INVENTION

The present invention relates to wireless communications and, in particular, to a method for performing a band request procedure.

State of the art

The IEEE (Institute of Electrical and Electronics Engineers) 802.16 standard provides techniques and protocols for supporting broadband wireless access. Its standardization began in 1999, and IEEE 802.16-2001 was approved in 2001. The IEEE 802.16 standard is based on a single-carrier physical layer called “Wireless MAN-SC”. Later, in addition to Wireless MAN-SC, Wireless MAN-OFDM and Wireless MAN-OFDMA were added to the physical layer in the IEEE 802.16a standard, approved in 2003. After the IEEE 802.16a standard was completed, the amended IEEE 802.16-2004 standard was approved in 2004. IEEE 802.16-2004 / Cor1 was issued in the form of an “amendment” in 2005 with the aim of resolving and correcting defects and errors of the IEEE 802.16-2004 standard.

The IEEE 802.16 Broadband Wireless Access Working Group is currently standardizing IEEE 802.16m based on IEEE 802.16e. IEEE 802.16m evolved from IEEE 802.16e.

Communication between the base station and the terminal is performed by downlink (DL) transmission from the base station to the terminal and uplink (UL) transmission from the terminal to the base station. A common IEEE 802.16e-based system profile supports a TDD (Time Division Duplex) scheme in which a downstream transmission and an upstream transmission are separated by time domains. A TDD scheme is a scheme in which uplink transmission and downlink transmission are performed over different time periods, while using the same frequency band. The TDD scheme is advantageous in that frequency selective scheduling is simplified due to the fact that the characteristics of the uplink and the characteristics of the downlink are mutually inverse. In IEEE 802.16m, both the TDD scheme and the FDD (Frequency Division Duplex Transmission) scheme are considered. An FDD scheme is a scheme in which downlink transmission and uplink transmission are performed simultaneously on different frequency bands. IEEE 802.16e uses a 5-millisecond TDD scheme frame, while IEEE 802.16m considers a 20 ms superframe for use with both the TDD scheme and the FDD scheme.

In IEEE 802.16e, when a mobile station (MS) needs to transmit data on the uplink, it performs a band request procedure (BW REQ). The band request procedure in IEEE 802.16e includes four steps: (1) transmitting a band request pointer; (2) transmitting a response message to a strip request indicator; (3) transmitting a band request message; (4) transmitting an uplink usage authorization message; and (5) uplink transmission. One of the predefined orthogonal codes is selected as a strip request indicator and transmitted over the competition channel. If the strip request indicator transmitted from the MS does not conflict with the strip request indicators from other MSs, the base station (BS) transmits an uplink grant message for transmitting the strip request message in response to the strip request indicator. Table 1 below shows an example of an uplink grant message for transmitting a band request message.

Table 1 Syntax Size (bit) Notes CDMA_Appointment_IE0 { - - Duration 6 - UIUC four UIUC for transmission Specifying Code Repetitions 2 0b00: No Code Repeat
0b01: Code Repeat 2 Used
0b10: Code Repeat 4 Used
0b11: Code Repeat 6 Used Frame number index four The least significant bits of the corresponding frame number Ranking Code 8 - Ranking Symbol 8 - Ranking subchannel 7 - Obligatory
BW request one 1: Yes
0: no } - -

After receiving an uplink grant message, the MS transmits a band request message on a specific radio resource. The band request includes information such as a connection identifier (CID) of the MS, the size of the requested radio resource, and the like.

After receiving the band request message, the BS transmits an uplink grant message including information regarding the size and position of the uplink radio resource for uplink data transmission to the MS with the corresponding CID. Table 2 below shows an example of an uplink grant message for uplink data transmission.

table 2 Syntax Size (bit) Notes UL-MAP_IE0 { - Cid 16 - Start time eleven - Subchannel index 5 - UIUC four - Duration 10 In OFDM Symbols Middle Field Repeat Interval 2 0b00: Introductory field only
0b01: Interval 5: Average field after every 4 data characters
0b10: Interval 9: Average field after every 8 data characters
0b11: Interval 17: Middle field after every 16 data characters if (UIUC == 4) -

Focused_Competition_
IE () 16 - if (UIUC == 13) - Subchannel_Network_EssenceIE () 12 - if (UIUC == 15) - UL_Extended_IE () Variable See relevant section. Nibble with insignificant information, if required four Fill to the nearest byte, should be set to 0 × 0 } - -

The MS transmits uplink data in an uplink radio resource indicated by an uplink grant message for uplink data transmission. In the transmission of upstream data, a header is added to the upstream data, including the CID of the MS and CRC (cyclic redundancy check) to check for errors in the data.

IEEE 802.16m inherits various communication services, such as EMBS (Enhanced Multicast and Unicast Service) for various multimedia services, multi-hop relay to improve service in the no-reception area, and femto cell for high-capacity service in homes and offices. A macrocell, a relay BS, and a femtocell can use different frequency bands in order to reduce interference. When a plurality of relay BSs or femtocells are located in one macrocell, intercell handover will often be performed, and accordingly, the MS will often perform a band request procedure. In addition, in the continuous provision of high-capacity real-time services such as video communications, delays in the band request procedure can lead to degradation of QoS (Quality of Service).

Thus, a method for efficiently performing a band request procedure is required in order to improve QoS of a wireless communication system.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a method for efficiently performing a strip request procedure.

To achieve these and other advantages, and in accordance with the purpose of the present invention, implemented and broadly described herein, the present invention provides a method for performing a band request procedure in a wireless communication system, including: transmitting a band request indicator and a band request message over a band request channel ; receiving an uplink grant message indicating an uplink radio resource in response to a band request indicator and a band request message; and transmitting uplink data after receiving the uplink grant message, wherein the uplink grant message includes information regarding the type of uplink grant message.

According to an illustrative embodiment of the present invention, the band request procedure can be performed quickly and efficiently.

Brief Description of the Drawings

1 shows a wireless communication system.

Figure 2 shows an example of a personnel structure.

3 is a flowchart illustrating an uplink data transmission process according to an illustrative embodiment of the present invention.

4 shows a 5-step strip request procedure according to an illustrative embodiment of the present invention.

5 shows a 3-step strip request procedure according to an illustrative embodiment of the present invention.

6 shows an example of an upstream data format used in a band request procedure.

7 shows another example of an upstream data format used in a band request procedure.

FIG. 8 shows a band request procedure for minimizing the amount of information in a band request message according to an illustrative embodiment of the present invention.

FIG. 9 is a flowchart illustrating a process of a method for selecting a band request procedure according to an illustrative embodiment of the present invention.

10 shows an example of a band request channel.

DETAILED DESCRIPTION OF THE INVENTION

The following technique can be used in various wireless communication systems, such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single-carrier frequency division multiple access (SC-FDMA), etc. CDMA can be implemented with radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented with radio technology such as Global System for Mobile Communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rate for GSM Evolution (EDGE). OFDMA can be implemented by such radio technology as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, EUTRA (Evolved UTRA), etc. UTRA is part of the universal mobile communications system (UMTS). 3GPP (Third Generation Partnership Project) LTE (Long Term Evolution) is part of the Enhanced UMTS (E-UMTS) using E-UTRA, which utilizes OFDMA on the downlink and SC-FDMA on the uplink. IEEE 802.16m is an evolution of IEEE 802.16e.

For explanatory purposes, IEEE 802.16m will mainly be described, but the technical concept of the present invention does not imply such a limitation.

1 illustrates a wireless communication system.

As shown in FIG. 1, a wireless communication system includes at least one base station (BS) 20. Each BS 20 provides a communication service to certain geographical areas (which are generally referred to as cells). Each cell can be divided into many zones (called sectors). Mobile station (MS) 10 may be stationary or mobile and may be referred to under various names, such as user equipment (UE), user terminal (UT), subscriber station (SS), wireless device, electronic assistant (PDA), wireless modem, portable device, etc. BS 20 generally refers to a fixed station that communicates with MS 10 and may be referred to by other names, such as Enhanced Node-B (eNB), Base Transceiver System (BTS), Access Point (AP), etc.

Hereinafter, a downlink (DL) is a link from a BS to an MS, and an uplink (UL) is a link from a MS to a BS. In the downlink, the transmitter may be part of the BS, and the receiver may be part of the MS. In the uplink, the transmitter may be part of the MS, and the receiver may be part of the BS.

Figure 2 shows an example of a personnel structure.

As shown in FIG. 2, the superframe includes a superframe header and four frames (F0, F1, F2 and F3). It is illustrated that the size of each superframe is 20 ms and the size of each frame is 5 ms, but the present invention does not imply such a limitation. The superframe header may be located in the initial part to which a common control channel is assigned. A common control channel is a channel used to transmit control information that can be shared by all UEs in a cell, such as information regarding frames constituting a superframe or system information.

One frame includes eight subframes (SF0, SF1, SF2, SF3, SF4, SF5, SF6 and SF7). Each subframe may be used for uplink or downlink transmission. Each subframe may include six or seven OFDMA symbols, but this is for illustrative purposes only. A time division duplex (TDD) scheme or a frequency division duplex (FDD) scheme may be applied to a frame. In the TDD scheme, each subframe is used for uplink transmission or downlink transmission for mutually different time periods at the same frequency. That is, the subframes in the TDD frame are divided into uplink subframes and downlink subframes in the time domain. In the FDD scheme, each subframe is used for uplink transmission or downlink transmission at different frequencies for the same time periods. That is, the subframes in the frame of the FDD scheme are divided into uplink subframes and downlink subframes in the frequency domain. Upstream and downstream transmission can occupy different frequency bands and can be performed at the same time.

A subframe includes at least one frequency division. Frequency partitioning includes at least one physical resource unit (PRU). Frequency partitioning may include localized PRUs and / or distributed PRUs. Frequency division can be used for fractional frequency reuse (FFR) or multicast and unicast translation services (MBS).

A PRU is defined as a basic physical unit for assigning resources, including a plurality of adjacent OFDM symbols and a plurality of adjacent subcarriers. The number of OFDM symbols included in the PRU may be equal to the number of OFDM symbols included in one subframe. For example, if one subframe includes six OFDM symbols, a PRU may be defined as including 18 subcarriers and 6 OFDM symbols. A logical resource block (LRU) is a basic logical block for distributed resource assignment and localized resource assignment. An LRU is defined by a plurality of OFDM symbols and a plurality of subcarriers and includes pilots used in the PRU. Accordingly, the desired number of subcarriers in one LRU depends on the number of assigned pilot signals.

A distributed resource unit (DRU) may be used to obtain gain from frequency spread. A DRU includes a group of subcarriers distributed in one frequency partition. DRU size is equal to PRU. The smallest unit of DRU formation is one subcarrier.

An adjacent resource unit (CRU) or localized resource unit may be used to obtain gain from frequency selective scheduling. CRU includes a localized group of subcarriers. CRU size is equal to PRU.

Next, a band request procedure will be described. A band request procedure is a procedure in which a mobile station (MS) requests a radio resource assignment from a base station (BS) in order to perform uplink transmission. An uplink radio resource is assigned to the MS through a band request procedure, and it transmits uplink data.

<Transmission of upstream data after power-up of the MS or after execution of handover>

3 is a flowchart illustrating an uplink data transmission process according to an illustrative embodiment of the present invention.

As shown in FIG. 3, when the power of the MS is turned on in the area of the BS cell or when the MS performs handover from the neighboring cell, the BS assigns the MS MS_ID for MS identification and a stream ID for connecting to some service (S110). A stream ID is a service-related ID used in relation to the MS to establish a specific service (e.g., voice call, video call, transmission of control information, etc.). Since different services can be provided by one MS, several stream IDs can be assigned to an MS. The stream ID may indicate the presence or absence of periodicity of service.

MS performs a competitive strip request procedure (BW REQ) (S120). The competitive band request procedure is performed so that the MS transmits a sequence of selected predetermined orthogonal codes on the band request channel competitively determined by different MSs. The band request channel includes a radio resource through which the MS can transmit a band request sequence and a band request message. The strip request channel includes a plurality of strip request segments. The band request segments may be allocated in the frequency domain or in the time domain. Each of the band request segments includes a plurality of adjacent subcarriers on a plurality of OFDM symbols. For example, a band request channel may include three distributed band request segments. Band request segments can be defined as six adjacent subcarriers on six OFDM symbols. The competitive lane request procedure includes a 3-step lane request procedure and a 5-step lane request procedure. The 3-step strip request procedure is achieved by reducing the process of the 5-step strip request procedure so as to transmit upstream data faster. While the 5-step strip request procedure is a general strip request procedure, the 3-step strip request procedure can be a fast strip request procedure. The 3-step strip request procedure and the 5-step strip request procedure will be described later. Through a competitive band request procedure, an uplink radio resource is assigned to the MS and it transmits initial uplink data. If the service period corresponding to the streaming ID provided by the MS and the data size are fixed, the BS may assign an uplink radio resource to the MS without requesting a band from the MS.

After transmitting the uplink data to the BS, the MS can transmit the next uplink data using a non-competitive band request procedure or interrogation information (Interrogation IE (Information Element)) (S130). A non-competitive band request procedure may be performed when the BS already knows the sequence that the MS should use to request the band, or when some radio resource is reserved for the band request so that the MS can make the band request without conflict with another terminal. Interview information is periodically provided regarding QoS (Quality of Service) and traffic characteristics. In a situation where the MS transmitted uplink data, when the uplink data to be transmitted subsequently is data of a stream corresponding to a service without periodicity, the MS performs a competitive band request procedure for transmitting uplink data. When the upstream data to be transmitted from the MS is the data of the flow corresponding to the service at periodic intervals, or when the size of the data changes, the BS can allocate a radio resource for a non-competitive band request from the MS or transmit a band request header using interrogation information. A service with periodicity or data that varies in size can include real-time services, such as a streaming service, real-time polling service (rtPS), advanced real-time polling service (ertPS).

Thus, since the MS can make a band request through a non-competitive band request or interrogation information, without performing a competitive band request procedure, regarding upstream data to be transmitted subsequently, a delay caused by the failure of the band request can occur in the competitive band request procedure. In a non-competitive band request procedure, a separate radio resource must be assigned to the MS, which may result in overhead. Thus, in order to reduce costs that may arise in a non-competitive band request procedure, and to reduce the delay in the band request procedure, a 3-step band request procedure can be performed.

Now, a process of a 5-step strip request procedure and a 3-step strip request procedure will be described.

<5-Step Strip Request Procedure Process>

4 shows a 5-step strip request procedure according to an illustrative embodiment of the present invention.

As shown in FIG. 4, the MS transmits a strip request indicator to the BS (S210). One of the predefined orthogonal or semi-orthogonal code sets may be selected as a strip request indicator. Type, length, etc. the orthogonal or semi-orthogonal code used as a strip request pointer is unlimited. A plurality of orthogonal or semi-orthogonal code sets may be provided, or other orthogonal or semi-orthogonal code sets may be used according to cells or sectors. The MS may transmit a first band request message including information required for bandwidth assignment, together with a band request indicator. The information required for bandwidth allocation may include MS_ID, Stream ID, scheduling type, and the like. Part or a reduced view of the information required to assign the bandwidth may be included in the transmitted first band request message along with the band request indicator in the 5-step band request procedure. The first band request message may include the whole part of the MS_ID. Part of the MS_ID can be configured in such a way that several bits, starting with LSB (least significant bit) or with MSB (most significant bit), the complete MS_ID are skipped. The strip request indicator may be transmitted on the competitive strip request channel. The first band request message may be a MAC (Media Access Control) layer, a higher layer of the physical layer.

The BS can find the sequence selected by the MS by comparing the full orthogonal or semi-orthogonal code sets with the strip request indicator received from the MS. The strip request indicator may not be transmitted on a predetermined strip request channel, or one or more strip request indicators may be transmitted. The BS finds the first lane request message based on the lane request pointer. When a CRC is included in the first band request message, error detection for the first band request message is performed based on the CRC. When the first band request message does not include a CRC, error detection for the first band request message can be performed based on RSSI (Received Signal Strength Indication), CINR (Carrier Power to Interference Ratio), and the like.

When the first lane request message, considering the lane request indicator, is not received, or when an error occurs, the BS may perform a 5-step lane request procedure. That is, the MS performs the strip request procedure only with the strip request pointer. When the first strip request message, taking into account the strip request indicator, is received without errors, the BS may perform a 5-step strip request procedure or a 3-step strip request procedure. Here, a case will be described where a 5-step strip request procedure is performed.

The BS may transmit an ACK (Acknowledgment) signal to the MS with respect to the strip request indicator (S220). The ACK signal may be transmitted for a certain period or may be skipped.

The BS may transmit an uplink (UL) grant message for the second band request message (S230). When the BS detects only the band request indicator, the BS transmits an uplink grant message for the second band request message. Hereinafter, an uplink grant message for a second band request message will be called a “control grant message”. The control authorization message may include the information shown below in Table 3.

Table 3 Information Note UL Type UL resolution when only a strip request pointer is detected BW REQ Pointer Confirmation Sequence Index, Region Information of the Received BW REQ Pointer Resource for BW REQ message BW REQ header field or non-competitive BW REQ field CRC or translational MS_ID Masking Type UL Resolution or MS_ID

The control authorization message may include (1) information regarding the type of uplink permission message, (2) confirming information regarding the band request indicator, (3) information regarding the assignment of the uplink radio resource, taking into account the second band request message, and (4) CRC etc.

The information regarding the type of uplink permission message is information for determining the type of permission message used in the 5-step strip request procedure and in the 3-step strip request procedure. Here, information regarding the type of uplink grant message is indicated for the uplink grant message for the case where only the strip request indicator is detected. Information regarding the type of uplink grant message may be transmitted through a separate resource area or may be masked in a CRC for transmission. For example, when a 12-bit MS_ID is masked in a 16-bit CRC, information regarding the type of uplink permission message can be masked in the remaining 4 bits and transmitted.

Confirmation information regarding the strip request indicator indicates a sequence index, resource area and the like, a strip request indicator, received by the BS. The orthogonal or semi-orthogonal code set used as the strip request indicator may be divided for various purposes, and the strip request pointer may indicate additional information regarding the purpose of the orthogonal or semi-orthogonal code set. For example, when an orthogonal or semi-orthogonal code set of a strip request indicator is classified for use according to a 5-step strip request procedure and a 3-step strip request procedure, confirmation information regarding the strip request pointer may indicate a threshold value taking into account the difference in the strip request procedures to indicate, whether or not a band request procedure is to be performed subsequently is a 3-step band request procedure or a 5-step band request procedure.

The uplink radio resource assignment information with respect to the second band request message may indicate a resource area for transmitting a band request message header to be transmitted from the MS subsequently, or a resource area for transmitting a non-competitive band request message in a non-competitive band request procedure.

CRC is used to detect errors for control permission messages. The MS_ID or information regarding the type of uplink grant message may be masked in the CRC. When the MS does not transmit the first lane request message or when the first lane request message contains an error, the BS cannot learn about the MS_ID from the MS. The BS may not mask the MS_ID or mask the translational MS_ID in the CRC. The translational MS_ID is arbitrarily assigned to the MS in order to carry out a further strip request procedure. When the translational MS_ID is not masked in the CRC, or when the bit size of the translational MS_ID is less than the bit size of the CRC, information regarding the type of uplink grant message included in the control grant message may be masked in the CRC.

The MS transmits a second uplink radio resource request message assigned by the enable control message (S240). The second band request message may be a MAC layer message. The second band request message may include the whole information required for bandwidth assignment, or may include the remaining information not included in the first band request message. The second band request message may include the full MS_ID, Stream ID, requested radio resource size, scheduling type, and the like.

The BS may transmit an ACK signal related to the second band request message (S250). The ACK signal may be transmitted in a predetermined period or may be skipped.

The BS transmits an uplink grant message for uplink data (S260). Hereinafter, an uplink grant message for uplink data will be called a “data grant message”. The data permission message in the 5-step band request procedure may include the information shown in Table 4 below.

Table 4 Information Note UL Type UL Resolution for UL Data Transfer BW REQ Pointer Confirmation Confirmation of a received BW REQ message and requested radio resource Resource for UL Data Position and size of the uplink radio resource for transmitting UL data CRC or translational MS_ID Masking Type UL Resolution or MS_ID

The data permission message may include (1) information regarding the type of uplink permission message, (2) confirming information regarding the band request message, (3) information regarding the assignment of the uplink radio resource taking into account the uplink data, and (4) CRC and t .P.

Information regarding the type of uplink grant message indicates that the message is an uplink grant message for uplink data transmission. Information regarding the type of uplink grant message may be transmitted through a separate resource area or may be masked in a CRC for transmission. Confirmation information regarding the band request message indicates whether or not the MS_ID, Stream ID, requested radio resource size, scheduling type and the like are included in the band request message received by the BS. Information regarding the destination of the uplink radio resource, taking into account the uplink data, indicates the position and size of the uplink radio resource assigned by the MS, reflecting the size of the radio resource requested by the MS. CRC is used to detect errors for data resolution messages. The full MS_ID or information regarding the type of uplink grant message may be masked in the CRC. When the full MS_ID bit size is less than the CRC bit size, information regarding the type of uplink grant message included in the data grant message may be masked in the CRC.

The MS transmits the uplink data by the assigned uplink radio resource according to the data permission message (S270). Upstream data may not include the full MS_ID. Since the BS is known for the full MS_ID, the transmission of the full MS_ID is optional.

When the MS transmits only a strip request indicator, a 3-step strip request procedure can be performed in the following case.

(1) This is the case when the terminal arbitrarily performs a 3-step strip request procedure. When the BS transmits an uplink grant message for the second band request message, the MS can randomly transmit uplink data instead of the second band request message. In this case, the BS can determine if this is the second band request message or upstream data after checking the type of header, etc. in data transmitted from MS. Accordingly, a 3-step strip request procedure omitting steps S240 to S260 may be performed.

(2) This is the case when the BS arbitrarily performs a 3-step strip request procedure. The BS may optionally transmit a data permission message instead of transmitting an uplink permission message (control permission message for a second band request message). The MS can determine if this is a control permission message or an information permission message for information regarding the type of uplink permission message. Thus, steps S230 to S250 can be omitted, and a 3-step strip request procedure can be performed.

<3-Step Strip Request Procedure Process>

5 shows a 3-step strip request procedure according to an illustrative embodiment of the present invention.

As shown in FIG. 5, the MS transmits a band request indicator and a band request message to the BS (S310). The strip request indicator and the strip request message may be transmitted on the competitive strip request channel. As a strip request indicator, one of the predefined orthogonal or semi-orthogonal sets may be arbitrarily selected. The transmission of a large amount of information on the competitive band request channel may cause unproductive consumption of radio resource, so the minimum information required to assign a bandwidth should be included in the band request message. The band request message may include MS_ID, QoS ID, Stream ID, buffer size indicating radio resource size, receive power level, and the like. The QoS ID is a QoS index containing the type of band request scheduling, priority, and the like. The band request message may include the full MS_ID or part of the MS_ID. The MS_ID part may contain some bits of the full MS_ID. Part of the MS_ID can be configured in such a way that several bits, starting with LSB (least significant bit) or with MSB (most significant bit), the complete MS_ID are skipped.

The BS may find the orthogonal or semi-orthogonal code selected by the MS by comparing the full orthogonal or semi-orthogonal code sets with the band request indicator received from the MS. The strip request indicator may not be transmitted on a predetermined strip request channel, or one or more strip request indicators may be transmitted. The BS finds a strip request message based on a strip request pointer. The BS can estimate the channel based on the band request message using the band request indicator and demodulate it. When a CRC is included in a band request message, error detection for the band request message is performed based on the CRC. When the band request message does not include CRC, error detection for the band request message is performed based on RSSI (Received Signal Strength Indication), CINR (Carrier Power to Noise Ratio) and the like. When the band request message is received without errors, the BS performs a 3-step band request procedure.

The BS may transmit an ACK signal with respect to the band request indicator and the band request message to the MS (S320). The ACK signal may be transmitted in a certain period or may be skipped.

The BS transmits an uplink grant message for uplink data (S330). An uplink permission message for upstream data may be referred to as a “data permission message”. The BS generates a data permission message by means of information included in the band request message transmitted from the MS and transmits it. In a 3-step band request procedure, a data permission message may include the information shown below in Table 5.

Table 5 Information Note UL Type UL resolution when both band request and message are detected Acknowledgment of the BW REQ Index and Message Sequence index of the received BW REQ pointer, MS_ID, field information Resource for UL Data Position and size of the uplink radio resource for transmitting UL data

CRC or translational MS_ID Masking Type UL Resolution or MS_ID

In a 3-step band request procedure, the data permission message may include (1) information regarding the type of uplink permission message, (2) confirming information regarding the band request pointer and the band request message, (3) information regarding the assignment of the uplink radio resource given upstream data and (4) CRC, etc.

Information regarding the type of uplink grant message indicates that the message is an uplink grant message when a strip request indicator and a strip request message are detected. Information regarding the type of uplink grant message may be transmitted through a separate resource area or may be masked in a CRC for transmission. For example, when a 12-bit MS_ID is masked in a 16-bit CRC, information regarding the type of uplink grant message can be masked in the remaining 4 bits and transmitted.

The confirming information regarding the strip request indicator and the strip request message indicates the sequence index of the strip request indicator, received by the BS, the fully received MS_ID or part of the MS_ID, Stream ID, requested radio resource size, scheduling type, resource area related to the received strip request (e.g., a pointer band request and frame number for which the message was transmitted).

Information regarding the destination of the uplink radio resource, taking into account the uplink data, indicates the position and size of the uplink radio resource assigned to the MS, reflecting the size of the radio resource requested by the MS.

CRC is used to detect errors for data resolution messages. The MS_ID or information regarding the type of uplink grant message may be masked in the CRC. When the BS knows the full MS_ID, the full MS_ID can be masked in the CRC. When only the MS_ID part is known to the BS, only this MS_ID part can be masked in the CRC, or the MS_ID part and the rest of the MS_ID can be masked as a predefined value (for example, 0) in the CRC. When the full MS_ID bit size is less than the CRC bit size, information regarding the type of uplink permission message included in the data permission message for the 3-step band request may be masked in the CRC.

The MS transmits the uplink data by the assigned uplink radio resource according to the data permission message (S340). The MS receives an uplink grant message, and when the frame number, sequence index, etc. in the band request message transmitted by the MS match, the MS transmits uplink data through the radio resource indicated by the BS. If the MS included the full MS_ID in the band request message and transmitted it, the MS does not have to include the full MS_ID in the upstream data and transmit it again. However, if the MS included only part of the MS_ID in the band request message and transmitted it, the MS must inform the BS of the complete MS_ID. When the 3-step strip request procedure is performed using the MS_ID part, this MS_ID part may be the same, although the full MS_ID is different, which may cause a conflict between different MSs. For example, when the Stream ID or scheduling type included in the band request message is different or the transmission frame number or sequence index is different, the band request message may be detected. However, if there are several MSs whose information is completely identical and only the complete MS_IDs are different, the BS cannot decode the strip request message, and the MS must attempt a 3-step strip request procedure again or must perform a 5-step strip request procedure. This may cause a delay in the band request procedure.

Thus, in order to prevent this problem, the MS can add an extended header including the full MS_ID or the rest, minus the original part, the full MS_ID, in the upstream data for the BS message of the full MS_ID. That is, the format of the upstream data may change according to whether the full MS_ID is included or not included in the strip request message in the strip request procedure. In addition, the format of the upstream data may vary according to whether the BS recognized or not recognized the MS_ID (station ID) of the MS to which the upstream bandwidth should be assigned.

<Upstream format in the strip request procedure>

6 shows an example of an upstream data format used in a band request procedure.

As shown in FIG. 6, in the 5-step strip request procedure or in the 3-step strip request procedure, when the full MS_ID is included in the strip request message and transmitted, the BS can be known as the complete MS_ID from the MS. Accordingly, when the BS assigns an upstream resource to the MS in a situation where it recognizes the MS_ID of the MS to which the upstream resource should be assigned, the MS is not required to report the full MS_ID when it transmits upstream data. MS includes the generic MAC header and CRC in the upstream data and transmits them.

The generic MAC header is used to transmit shared data. A generic MAC header includes many fields and can be used for both downstream and upstream transmissions. Fields included in the generic MAC header include HT (Header type), EH (Extended header indicator), Stream ID, EKS (Encryption Key Sequence), Length, etc. HT indicates the type of header. EH indicates the presence or absence of an extended header after a generic MAC header. The stream ID indicates the address of the stream, EKS indicates the encryption sequence, and the length indicates the length of the useful information. The number in brackets for each field indicates the number of bits in the field. The number of bits in each field is unlimited.

7 shows another example of an upstream data format used in a band request procedure.

As shown in FIG. 7, in a 3-step strip request message, when a strip request message is transmitted in a situation where a part of the MS_ID is included or nothing is included in the strip request message, the BS cannot know the full MS_ID from the MS. In addition, when only the band request indicator is transmitted in the 5-step bandwidth request, the BS cannot be known by the MS_ID from the MS. Thus, the MS must inform the BS the full MS_ID in the uplink transmission. MS includes a generic MAC header, an extended header, and CRC in the upstream data and transmits them.

Whether to include the extended header is indicated by the EH field of the generic MAC header. The extended header includes fields such as Last, Type, Content, etc. The "Last" field indicates whether the extended header is the last extended header. The upstream data may include a plurality of extended headers, and the “Last” field is not assigned to the last extended header, thus indicating the last extended header. “Type” indicates the type of the extended header, and “Content” includes various types of information according to the “Type”. The length of the “Content” may vary according to the information included.

When the full MS_ID is included in the upstream data, the full MS_ID can be included in the "Content" field of the extended header. Or, when the rest, minus the original part, the full MS_ID is included in the upstream data, the remaining MS_ID can be included in the “Content” field of the extended header. The type MS_ID included in the "Content" field may be indicated according to the type from the "Type" field. When additional uplink radio resource is required in the uplink transmission, the MS can include the size of the required bandwidth along with the full MS_ID in the extended header and transmit it. The size of the required bandwidth can also be included in the "Content" field and indicated according to the type from the "Type" field.

In a 3-step band request procedure, the case where a part of the MS_ID is transmitted on the competitive band request channel and only the MS to which the upstream radio resource is assigned, transmits the full MS_ID or the rest of the MS_ID in the upstream data, can be more efficient than when all MS transmit the full MS_ID on the competitive band request channel.

<Band request procedure taking into account the reliability of the band request pointer>

A terminal that makes an initial connection, a terminal that performs handover, or a terminal that has been idle for a long period of time may not be exactly aware of SINR (Signal to noise interference ratio) due to inaccurate power control, so it may not be able to evaluate a suitable threshold value for comparing the strip request pointer. This may degrade the performance of detecting a strip request pointer in a 5-step strip request procedure or a 3-step strip request procedure. In particular, serious performance degradation can be caused in a 3-step band request procedure in which a channel, taking into account the band request message, is estimated using the detected band request indicator and demodulated. Thus, in order to prevent performance degradation in the band request procedure, the amount of information included in the band request message transmitted together with the band request indicator should be minimized.

FIG. 8 shows a band request procedure for minimizing the amount of information in a band request message according to an illustrative embodiment of the present invention.

As shown in FIG. 8, the MS transmits a band request indicator and a band request message to the BS (S410). In order to ensure reliability of the performance of evaluating the strip request indicator, the strip request message includes a minimum amount of information. For example, a band request message may include at least any of the following information elements: QoS ID and buffer size or CRC. QoS ID is a QoS index containing the type of planning, priority, etc. request strip. The buffer size indicates the size of the radio resource requested by the MS. That is, MS_ID from MS, Stream ID, etc. are not included in the band request message. Accordingly, the BS may perform a band request procedure with the unknown of the MS submitting the band request.

The BS may transmit an ACK signal with respect to the strip request indicator and the strip request message to the MS (S420). The ACK signal may be transmitted in a certain period or may be skipped.

The BS cannot know which terminal, using which sequence, transmitted the strip request indicator, therefore, it performs a CRC check on all orthogonal or semi-orthogonal codes used as strip request indicators.

When a CRC error is not detected from some orthogonal or semi-orthogonal code, the BS transmits an uplink grant message including information regarding the band request message (QoS ID or buffer size) received together with the point in time when the corresponding orthogonal or semi-orthogonal code and A request pointer strip has been transmitted. The point in time when the strip request indicator has been transmitted can be expressed by at least any of the following information elements: frame number, slot, transmission capability, subframe number, band request channel index.

An uplink permission message may be transmitted at an arbitrary point in time or a fixed point in time. (1) When an uplink permission message is transmitted at an arbitrary point in time, the uplink permission message should include, as any of the following items of information: frame number, slot, transmission capability, subframe number, band request channel index, i.e., a point in time when the strip request pointer was passed. (2) When an uplink grant message is transmitted at a fixed point in time, if the MS is aware of information regarding the possibility of transmission, a band request channel index and the like, it may know a point in time when the uplink grant message is transmitted.

In a situation where the MS receives the uplink grant message, when the band request message transmitted from the MS, the transmission time, sequence, and the like are the same, the MS transmits uplink data on the uplink radio resource indicated by the BS (S440). MS_ID from MS, Stream ID, etc. are included in the header of the upstream data and transmitted. The stream ID may be included in the generalized MAC header of the upstream data, and the MS_ID from the MS may be included in the extended header. The BS can recognize the MS requesting the bandwidth by the MS_ID and Stream ID included in the upstream data. When an MS has upstream data for subsequent transmission, it can transmit a band request message in uplink data in a nested manner.

Moreover, when the BS does not have a radio resource that can be immediately assigned, although no CRC errors have been detected with respect to the band request message, the BS can transmit an ACK signal. In this case, the BS cannot know which of the MSs requested the bandwidth, therefore (1) it can broadcast the corresponding sequence and the band request message on a separate channel, (2) it can transmit an uplink grant message with a predetermined value (for example, 00 ... 0) or (3) it can include a pointer (for example, 0 indicates data transmission after a certain time, and 1 indicates immediate transmission) in relation to the ACK signal in the uplink permission message.

Thus, by the method of executing the strip request indicator and the strip request message in a situation where the BS unknown to the MS requesting the bandwidth, the reliability of the strip request indicator and the strip request message can be increased. In addition, since only a minimum amount of information is included in the strip request message, the decoding overhead of the strip request message can be reduced and the duration of the strip request procedure can be reduced. When several MSs simultaneously transmit a band request message including the same information, these MSs are likely to conflict, but the case where the sequence index used as a band request indicator is a QoS ID included in the band request message, or the size of the buffer is the same, unlikely. Thus, an accurate and quick lane request procedure can be performed without a problem in terms of reliability of detecting a lane request pointer due to failure of a suitable threshold value for comparing a lane request indicator from MS or performance degradation due to a lane request indicator conflict. Furthermore, even when two or more MSs use the same band request indicator, if only one MS has successfully passed the CRC check, the usual 3-step band request procedure can be performed. When an error occurs in the CRC check regarding the band request message, the BS may perform a 5-step band request procedure by detecting the band request pointer using a threshold value.

In performing the 5-step band request procedure, the MS can transmit the first band request message without including the MS_ID from the MS. That is, the 5-step band request procedure can be performed in a situation where the BS is not known to the MS requesting the bandwidth. In this case, the MS may include its MS_ID in the second band request message or in the upstream data and transmit it. Even in the 5-step lane request procedure, the reliability of the lane request indicator and the lane request message can be increased.

<Method for selecting a strip request procedure>

As described above, the 3-step lane request procedure is for quickly performing a lane request, and the 5-step lane request procedure is for reliably performing the competitive lane request procedure. The entity determining which of the band request procedures to execute may be a BS or an MS.

FIG. 9 is a flowchart illustrating a process of a method for selecting a band request procedure according to an illustrative embodiment of the present invention.

As shown in FIG. 9, the MS transmits a band request indicator or a band request message to the BS together with a band request indicator to request a bandwidth to the BS (S510). In a 3-step lane request procedure, the MS transmits a lane request indicator and a lane request message. In a 5-step strip request procedure, the MS can only transmit a strip request indicator, or a strip request message, together with a strip request indicator.

The BS may optionally perform a 3-step strip request procedure or a 5-step strip request procedure by a strip request indicator or a strip request message received from the MS (S520). The MS may select the desired band request procedure during the transmission of the band request indicator or the band request message, and the BS may select the band request to execute while receiving the strip request indicator or the band request message.

Table 6 below shows an example of criteria for selecting a band request procedure in a BS or MS.

Table 6 Selective Entity Selection criteria Strip request procedure BS Bandwidth and Message Request Pointer Reception Situation 3-step: lane request indicator and message are received or only lane request indicator is accepted
5-step: only the strip request pointer is accepted Ms A band request message is being transmitted or not being transmitted 3-step: lane request indicator and message are transmitted or only lane request indicator is transmitted
5-step: only the strip request pointer is transmitted Subset Distinction by Strip Request Pointer Distinction according to type of service
3-step: real-time service sequence is transmitted
5-step: the sequence associated with the non-real-time service is transmitted

According to an arbitrary choice,
3-step: a sequence is transmitted for a 3-step strip request
5-step: a sequence is transmitted for a 5-step strip request

When the band request is transmitted together with the band request indicator, the BS may check the reception situation of the band request indicator and the band request message to determine the band request procedure. When the strip request message is received together with the strip request indicator, a 3-step strip request procedure is performed. When only the strip request indicator is received, for example, when the MS transmits only the strip request indicator or when the BS can detect only the strip request indicator due to an error occurring in the strip request message, a 5-step strip request procedure can be selected. Either the BS or the MS can arbitrarily select a 3-step band request procedure. Of course, when the BS cannot receive both the strip request indicator and the strip request messages, the strip request procedure fails, and the MS retries the strip request procedure.

When it is desirable for the MS to execute the 3-step strip request procedure, it can only transmit the strip request indicator, and when for the MS it is desirable to perform the 5-step strip request procedure, it can transmit the strip request message along with the strip request indicator to determine the strip request procedure.

An orthogonal or semi-orthogonal code can be used as a strip request pointer sequence. Thus, the strip request indicator can be transmitted on the strip request channel according to the CDM (Code Division Multiplexing) method, and the sequence of the strip request indicator can be easily distinguished. The code set used as a strip request indicator may be varied as a subset to determine a strip request procedure.

A subset of the strip request indicator may be different according to the type of service. For example, the type of service includes a real-time service, such as VoIP (Voice over Internet Protocol), and a non-real-time service, such as a shared data service. The subset of the strip request indicator may be divided into a sequence related to a real-time service and a sequence related to a non-real-time service. A real-time service is susceptible to delays, and a non-real-time service is relatively immune. An accelerated band request procedure is required for a service susceptible to delays. Thus, when the service for the MS is susceptible to delays, the MS can select and transmit the sequence related to the service in real time, and when the service for the MS is immune to delays, the MS can select and transmit the sequence related to the service in non-real time. That is, the MS may optionally transmit a subset of the strip request indicator according to the type of service. When a non-real-time service sequence is transmitted from the MS, the BS can perform a 5-step band request procedure. When a sequence relating to a real-time service is transmitted from the MS, the BS may perform a 3-step band request procedure. When a data packet with a standardized size, such as VoIP, is used, the BS can assign a radio resource with a predetermined specific size to perform a 3-step band request procedure.

The subset of the strip request indicator may differ in sequence for a 3-step strip request and sequence for a 5-step strip request. Distinguishing sequence information for a 3-step strip request and sequences for a 5-step strip request or index information about distinguishable sequences can be broadcast. MS generates a number and compares it with a threshold value based on discriminating sequence information. For example, when 19 sequences are provided as strip request pointers, the BS can define 17 sequences as sequences for a 5-step strip request, and the remaining two sequences as sequences for a 3-step strip request, and inform the MS accordingly on the broadcast channel. When a band request is required, the MS generates a certain number q and compares it with a threshold value p. The MS can choose either a 3-step strip request procedure or a 5-step strip request procedure depending on whether a> p is satisfied. For example, in the case where the threshold value p is 2/19 and 0 <q≤1, if q> p, a 5-step strip request procedure can be performed, and if q≤p, a 3-step strip request procedure can be performed. When the 3-step strip request procedure is selected, the MS transmits one of the sequences for the 3-step strip request procedure on the strip request channel. When the 5-step strip request procedure is selected, the MS transmits one of the sequences for the 5-step strip request procedure on the strip request channel.

When an MS performing a 5-step strip request procedure and an MS performing a 3-step strip request procedure transmit a strip request indicator on one strip request channel without sequence discrimination, the BS cannot know which of the MS performs a 3-step request procedure lanes, and which performs a 5-step lane request procedure. Thus, this problem can be solved by distinguishing a subset of the strip request pointer according to the strip request procedure.

The strip request indicator may be included in the pilot of the strip request channel for transmission. The band request message may be included in a data signal of the same band request channel for transmission.

10 shows an example of a band request channel.

As shown in FIG. 10, a band request channel may include at least one band request segment. A band request channel may contain three distributed band request segments. That is, the band request segments included in the band request channel may be distributed in a frequency domain and a time domain in a distributed manner. Band request segments may include multiple OFDM symbols in the time domain and include multiple subcarriers in the frequency domain. Band request segments may include six adjacent subcarriers in six OFDM symbols.

The band request segments may include a plurality of pilot signals (P) and a plurality of data signals (remainder after subtracting P). The strip request sequences can be mapped to the pilot signals of the strip request segments, and the strip request messages can be mapped to data signals. For example, the band request segments may include 19 pilots and 17 data signals. The strip request sequences may be mapped to a plurality of pilot signals, based on which channel estimation of the strip request channels and user discrimination can be performed.

All of the above functions can be performed by processors, such as a microprocessor, control means, microprocessor control means, ASIC (Specialized Integrated Circuit) and the like, according to software tools, program codes and the like configured to perform these functions. The design, development, and implementation of codes may be apparent to those skilled in the art based on the description of the present invention.

Since the illustrative embodiments can be implemented in various forms without going beyond the scope of the invention, it should be understood that the above embodiments are not limited to any of the details of the above description, unless otherwise stated, but should be construed in full within the scope defined by the attached claims. Thus, various changes and modifications, not going beyond the scope of the formula or equivalents of such a volume, are intended to be covered by the appended claims.

Claims (14)

1. A method for executing a bandwidth request (BR) for uplink transmission in a wireless communication system, the method being executed on the terminal side, comprising:
transmitting, from the terminal to the base station (BS), a first signal containing a BR pointer including a sequence and a BR message containing data related to the band request, the sequence included in the BR pointer being selected from orthogonal sequences or quasi-orthogonal sequences;
moreover, the BR message further comprises a cyclic redundancy check (CRC) for error detection, the first signal is transmitted on the BR channel containing many BR segments, and each BR segment consists of many adjacent subcarriers in the frequency domain on the set of adjacent multiplexing symbols with orthogonal frequency division (OFDM) in the time domain. 2. The method according to claim 1, in which, when the BR message is decoded, the method for performing a band request further comprises:
receiving, in response to the BR message, a second signal indicating permission for uplink transmission; and
transmitting, in response to an uplink grant, uplink data to a base station. 3. The method according to claim 1, in which, if an error is detected, the method for performing a strip request further comprises:
receiving, in response to the first signal, a third signal indicating permission for the band request message;
transmission, in response to permission, of a band request message; and receiving, in response to the band request message, permission for uplink transmission. 4. The method of claim 1, wherein the data associated with the band request is associated with at least a portion of the identifier (ID) for the terminal, and the ID consists of 12 bits. 5. The method according to claim 1, in which each BR segment consists of 6 adjacent subcarriers in the frequency domain on 6 adjacent OFDM symbols in the time domain. 6. The method according to claim 1, in which the BR channel consists of three BR segments, and three BR segments are distributed in the frequency domain. 7. The method of claim 1, wherein the lane request is a competitive lane request. 8. A terminal performing a band request (BR) for uplink transmission in a wireless communication system, the terminal comprising:
a radio frequency unit configured to transmit, to a base station (BS), a first signal containing a BR pointer including a sequence, and a BR message containing data related to the band request, the sequence being included in the BR pointer is selected from orthogonal sequences or quasi-orthogonal sequences;
moreover, the BR message further comprises a cyclic redundancy check (CRC) for error detection, the first signal is transmitted on the BR channel containing many BR segments, and each BR segment consists of many adjacent subcarriers in the frequency domain on the set of adjacent multiplexing symbols with orthogonal frequency division (OFDM) in the time domain. 9. The terminal of claim 8, in which, when the BR-message is decoded, the radio frequency unit is additionally configured with the possibility of:
receiving, in response to the BR message, a second signal indicating permission for uplink transmission; and
transmitting, in response to permission for uplink transmission, uplink data to the base station. 10. The terminal of claim 8, in which, if an error is detected, the radio frequency unit is additionally configured with the possibility of:
receiving, in response to the first signal, a third signal indicating permission for the band request message;
transmitting, in response to permission, a band request message; and receiving, in response to the band request message, an uplink grant. 11. The terminal of claim 8, in which the data associated with the request band, associated with at least part of the identifier (ID) for the terminal, and the ID consists of 12 bits. 12. The terminal of claim 8, in which each BR segment consists of 6 adjacent subcarriers in the frequency domain on 6 adjacent OFDM symbols in the time domain. 13. The terminal of claim 8, in which the BR channel consists of three BR segments, and three BR segments are distributed in the frequency domain. 14. The terminal of claim 8, wherein the lane request is a competitive lane request.

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