KR20110094587A - Method and apparatus for processing received packet for real time service - Google Patents

Abstract

PURPOSE: A reception packet processing method for a real time service is provided to prevent the loss of reception packet in a real time service. CONSTITUTION: An MAC(Medium Access Control) layer unit(1220) requests the retransmission of a MAC PDU(Packet Data Unit) in which an error is generated. If the MAC PDU is not successively delivered, the MAC layer unit transmits the RLC(Radio Link Control) PDU which is included in the successively received MAC PDU to an TLC layer unit. An RLC layer(1230) receives the RLC PDU from the MAC layer unit. The RLC layer unit configures an RLC SDU(Service Data Unit).

Description

Apparatus and method for processing of received packets for real-time services in high-speed wireless communication systems}

The present invention uses a High Speed Downlink Packet Access (HSDPA) / HSUPA (High Speed Downlink Packet Access) system, which is one of the third generation mobile communication systems, to process a received packet for a real time service in a high speed wireless communication system supporting a real time service. The present invention relates to a method and apparatus, and more particularly, to receive sequential reception of data when data is received out of order in a medium access control (MAC) layer through a wireless channel in a reception apparatus of an HSUPA system or an HSDPA system. It does not wait and immediately transfers to the Radio Link Control (RLC) layer, and the RLC layer does not immediately discard the incompletely transmitted packet, but recovers it through the subsequent retransmission process and transfers it to the upper layer, thereby being sensitive to delay time. Receive packet processing method that can prevent the loss of received packet in real-time service and Relates to a device.

High-Speed Downlink Packet Access (HSDPA) has adopted various technologies that can improve downlink transmission speed up to 14.4Mbps in the existing R99 wideband code division multiple access (WCDMA) system.

HSDPA technology, which supports high data rate, introduces 16-QAM (4bits / symbol), which increases the number of transmitted bits per symbol compared to the existing QPSK. It adopts AMC (Adaptive Modulation & Coding) technology that applies dynamically.

In addition, HARQ (Hybrid ARQ) technology combining forward error correction (FEC) and automatic repeat request (ARQ) is applied to quickly recover errors occurring in the physical layer, and multiple channelization codes are simultaneously applied to one terminal. It uses a multi-code technique (up to 15) to allocate.

In addition, the TTI is shortened to 2ms, and performs a fast packet scheduling function that can freely allocate downlink radio resources every TTI based on downlink quality information sent by the terminal.

In addition, the HSDPA reduces the complexity of the system by fixing the spreading factor (SF) to 16 regardless of the data rate. Unlike the existing CDMA system, by changing the number of codes used and the modulation and coding scheme (MCS) used in each code channel without controlling the data transmission rate by the spreading coefficient Support. The maximum transmission rate that can be supported by the HSDPA system is 14.4 Mbps using 15 code channels and 16QAM modulation in each code channel.

On the other hand, HSUPA (High-Speed Uplink Packet Access) provides up to 5.76Mbps by improving the uplink transmission speed and reducing the transmission delay time. HSUPA can coexist with existing WCDMA because it uses the basic functions such as cell selection, synchronization, random access, and mobility control procedure used in the existing R99 WCDMA.

HSUPA has adopted various technologies to support high data rates on the uplink. The terminal can quickly retransmit an error packet by using HARQ, and can use up to four code channels simultaneously. In addition, since the SF available in the code channel is reduced to 2, the maximum transmission rate that one code channel can support is 1.96 Mbps.

The protocol structure of the HSDPA / HSUPA system is located at the bottom of the physical layer that supports wireless transmission using WCDMA, followed by a medium access control (MAC) layer that supports dynamic access and sharing of media, and reliable transmission. It consists of a radio link control (RLC) layer.

The terminal includes the physical layer, the MAC layer, and the RLC layer in one entity, but in the network, the protocol layer may be divided. That is, the physical layer and the MAC layer are located in the base station and the RLC layer is located in a radio network controller (RNC).

In each protocol layer, a header is added to a service data unit (SDU), which is a data format transmitted from a higher level, to configure a PDU (protocol data unit), which is a unique data format. For example, data transferred from the RLC layer to the MAC layer is called an RLC PDU or MAC SDU.

HSDPA / HSUPA supports retransmission of failed packets in RLC layer and MAC layer. The retransmission function performed in the RLC layer observes a sequence number (SN) included in a header of an RLC PDU, and considers a packet not sequentially transmitted as an error and retransmits the packet. On the other hand, the retransmission function performed in the MAC layer is a function associated with the physical layer. If a decoding process of a newly transmitted packet fails, the retransmission function is stored without discarding the packet and then decoded in combination with the retransmitted packet. Since the retransmission of the RLC is additionally performed on the packet which is not recovered in the MAC layer, considering the delay time of the data, it is necessary to recover the packet through the retransmission function of the MAC.

The MAC layer of HSDPA / HSUPA includes additional functions to complement the retransmission of the RLC layer. This function is called reordering. The MAC layer delivers only the packets sequentially received to the RLC layer. To support this function, the receiving MAC layer stores the received packet and manages the reordering queue supporting sequential transmission. If the data is not stored in the reordering queue sequentially, it waits until the missing data is received, and delivers only the sequentially received data to the upper layer.

The reason why only data sequentially received in the reordering queue is delivered to the upper layer is to prevent the change of the RLC layer defined in the existing R99. That is, in the existing RLC layer, if the RLC PDUs are not received in order, data may be determined to be lost during transmission. However, in the MAC layer, reception of some data may be somewhat delayed by the HARQ function. Therefore, the MAC layer sequentially delivers data to higher layers so that the RLC layer does not need to retransmit data unnecessarily.

1 is a diagram illustrating an example of a reordering function performed by a receiving apparatus of a conventional HSDPA / HSUPA system.

In the case of Figure 1, the structure of the MAC PDU (Packet Data Unit) is briefly expressed, the transmission order is specified by a serial number called a transmission sequence number (TSN). In FIG. 1, 'H' means a set of header information except for TSN.

In the receiving device, TSN = 4 was received after TSN = 1, 2 and TSN = 3 was not received. TSN = 1,2 are delivered to the RLC layer immediately because they are received in sequence, but the MAC PDU with TSN = 4 must wait until the MAC PDU with TSN = 3 is received.

Such operation of the MAC layer may be appropriate for non-real time packet data which is not sensitive to delay time. However, in a real-time service, the longer the delay time, the lower the value of the information. If the received packet is not delivered to the higher layer because the previous data is not received, more information may be lost.

For example, assuming a case of transmitting a voice packet in uplink using HSDPA / HSUPA, the RNC should deliver a voice packet every 20 ms to the MSC (Mobile Switching Center). Assuming that voice packets 1, 2, and 4 are received in turn in the MAC layer, packets 1 and 2 are delivered to the RLC layer and delivered to the MSC in accordance with the RNC's transmission cycle, but if packet 3 is not received, Packet 4 is also not delivered to the RLC layer. If packet 3 is not delivered to RNC by the time of delivering packet 4 to the MSC, there is a problem that both packets should be discarded even if packet 3 arrives later.

Therefore, for latency-sensitive services such as real-time services, the MAC layer needs to be supplemented to reduce packet loss.

An object of the present invention for solving the above problems, when providing a real-time service through the HSUPA system or HSDPA system, if the MAC PDU is received in a non-sequential order to the medium access control (MAC) layer through the radio channel in the receiving device RLC SDUs are transferred to the RLC layer immediately without waiting for all the previous RLC PDUs to be received, and the RLC SDUs are recovered when the RLC SDUs, which are incompletely delivered at the RLC layer, are not immediately discarded and recovered through a subsequent retransmission process. The present invention provides a method and apparatus for processing a received packet that can prevent loss of a received packet in a delay-sensitive real-time service by transmitting to a higher layer.

According to an aspect of the present invention, there is provided a receiving packet processing apparatus comprising: a receiving packet processing apparatus using HSUPA / HSDPA technology, which is a high-speed wireless communication system, comprising: a physical layer unit for receiving packet data through a wireless channel; Receives a MAC PDU successfully received from the physical layer unit, requests retransmission of an errored MAC PDU, and RLC PDU included in the successfully received MAC PDU even if the MAC PDU is not sequentially transferred to the next RLC A MAC layer unit for transferring to the layer unit; And an RLC layer unit configured to receive the RLC PDU from the MAC layer unit, configure an RLC SDU, and deliver the RLC PDU to a next higher layer unit.

The apparatus may further include an upper layer unit which receives the RLC SDU from the RLC layer unit and delivers the RLC SDU to another layer or another node.

In addition, the MAC layer is a MAC-hs sublayer supporting HSDPA technology or MAC-es sublayer supporting HSUPA technology.

In addition, the MAC layer unit immediately delivers the RLC PDU to the RLC layer unit in case of a real-time service, wherein the real-time service includes a voice service.

In addition, the RLC layer unit generates the RLC SDU through retransmission and payload concatenation / division for the MAC PDU received from the MAC layer unit.

In addition, the upper layer unit stores the RLC SDU and delivers the packet to another upper layer or another network node in accordance with the transmission time of the real-time service.

In addition, the upper layer unit discards the packets when the transmission time has passed when the RLC SDU is received from the RLC layer unit.

When the MAC layer unit receives a MAC PDU successfully received for the packet data from the physical layer unit in case of a non-real-time service, the payload of the MAC PDU is received only when all previous packets are successfully received. Is transmitted to the RLC layer unit.

On the other hand, the received packet processing method according to the present invention for achieving the above object, the received packet processing method of a device including a physical layer unit, MAC layer unit, RLC layer unit and higher layer unit, (a) the physical layer Receiving packet data over an additional radio channel; (b) the MAC layer unit receives a successfully received MAC PDU of the packet data from the physical layer unit, and immediately delivers the successfully received MAC PDU to the RLC layer even if previous packets are not sequentially transmitted. step; (c) the RLC layer receiving the successfully received MAC PDU from the MAC layer unit and configuring the RLC SDU to deliver to the upper layer unit; And (d) receiving the RLC SDU from the RLC layer unit and delivering the RLC SDU to another layer or another node.

In addition, in step (b), a request for retransmission of a packet in which an error occurs among the received packet data is performed.

In addition, step (b) is performed through the MAC-hs sublayer supporting HSDPA technology or the MAC-es sublayer supporting HSUPA technology.

Also, in the step (b), in case of a real-time service, the payload of the successfully received MAC PDU is immediately transmitted to the RLC layer unit. At this time, the real-time service includes a voice service.

In addition, in the step (c), the MAC PDU received from the MAC layer unit is generated as the RLC SDU through retransmission and payload concatenation / division, and delivered to the upper layer unit.

In addition, the step (d) stores the RLC SDU and delivers the packet to another upper layer or another network node in accordance with the transmission time of the real-time service.

Also, in the step (d), when the RLC SDU is received from the RLC layer unit, if the transmission time has passed, the corresponding packets are discarded.

And, in the case of the non-real-time service, when receiving the MAC PDU successfully received for the packet data from the physical layer unit, the step (b) of the MAC PDU only if all the previous packets have been successfully received Deliver the payload to the RLC layer.

Since the MAC layer of the receiving side of the existing HSDPA / HSUPA system delivers only packets that arrive in sequence to the upper layer, even if the packets arrive in advance, they are not delivered to the upper layer unless the previous packet arrives. Since there is a problem that it may not be transmitted at an appropriate time due to a long time, the MAC layer according to the present invention can transmit the packets randomly or non-sequentially according to the type of service. Receive packets can be processed accordingly.

According to the present invention, since the packet of the real-time service is not discarded unnecessarily due to excessive delay time of the lower layer, the quality of service can be improved.

1 is a diagram illustrating an example of a reordering function performed by a receiving apparatus of a conventional HSDPA / HSUPA system.
2 is a diagram illustrating a radio access interface protocol structure of a WCDMA system to which the present invention is applied.
3 is a diagram illustrating a change in the MAC layer according to the introduction of the HSDPA technology and HSUPA technology in the present invention.
4 is a diagram illustrating a MAC-hs sublayer structure of UTRAN used as an example of the present invention.
5 is a diagram illustrating the structure of the MAC-hs sublayer of a terminal used as an example of the present invention.
6 is a diagram illustrating the structure of a MAC-hs PDU used as an example of the present invention.
7 is a diagram illustrating a structure of a MAC-e / MAC-es sublayer of a terminal for supporting HSUPA as an example of the present invention.
8 is a diagram illustrating an internal structure of a MAC-e sublayer located in a base station.
9 is a diagram illustrating an internal structure of a MAC-es sublayer located in an RNC.
10 is a diagram showing the structure of a MAC-es PDU according to the present invention.
11 is a diagram illustrating a process of configuring MAC-e PDUs by MAC-es PDUs according to the present invention.
12 is a block diagram schematically showing the configuration of a receiving packet processing apparatus for a real-time service according to an embodiment of the present invention.
13 is a flowchart illustrating a method of processing a received packet according to an embodiment of the present invention.
14 is a diagram illustrating a data processing performed by a MAC layer unit according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating a radio access interface protocol structure of a WCDMA system to which the present invention is applied.

That is, FIG. 2 illustrates a structure of a radio access interface protocol between a terminal and a universal terrestrial radio access network (UTRAN) based on the WCDMA radio access network standard. The wireless access interface protocol of FIG. 2 consists of a physical layer (PHY), a data link layer, and a network layer horizontally, and vertically controls a control plane for transmitting control signals and a data plane for transmitting data information. It is divided into user planes. The user plane is an area in which traffic information of a user, such as voice or an IP packet, is transmitted, and the control plane is an area in which control information necessary for maintaining and managing an interface or a call of a network is transmitted.

The physical layer (PHY) is responsible for the transmission of information using radio waves, and is connected to the upper layer of the medium access control (MAC) layer through transport channels. Data transmitted to the physical layer through a transport channel is transmitted to a receiver by applying various coding and modulation methods suitable for a wireless environment.

The MAC layer delivers data using the proper mapping between logical and transport channels. Logical channels are provided with various logical channels according to the type of information transmitted to the channels connecting the upper layer and the MAC layer.

The Radio Link Control (RLC) layer may configure an RLC PDU of an appropriate size for wireless transmission and perform an Automatic Repeat Request (ARQ) function that is responsible for retransmission of an RLC PDU lost during transmission. The sender RLC layer configures an appropriate RLC PDU for transmission by segmentation and concatenation of an RLC Service Data Unit (SDU) delivered from the upper layer, and the receiver RLC layer recovers the original RLC SDU. Performs connection and partitioning functions for In the RLC layer, there is an RLC buffer for storing RLC SDUs or RLC PDUs.

The PDCP (Packet Data Convergence Protocol) layer is located on top of the RLC layer and supports data transmitted through a network protocol such as IPv4 or IPv6 efficiently through the air interface. In particular, the PDCP layer may use a header compression technique that compresses header information of a packet for efficient transmission of an IP packet.

The RRC layer is defined only in the control plane and includes all functions for managing and controlling radio resources. In addition, lower layers can be set directly.

On the other hand, the HSDPA and HSUPA physical layers that support high data rates differ significantly from the previous Release 99.However, the upper layer minimizes the changes caused by the introduction of HSDPA / HSUPA and backward compatibility with previous systems. Is guaranteed.

HSDPA and HSUPA applied physical layer technologies such as AMD (Adatpive Modulation and Coding), Hybrid ARQ, 16-QAM (Quadrature Amplitude Modulation), and high-speed scheduling to support high data rates. Some features of the MAC layer have also been modified. However, protocol layers located above the MAC layer hardly change. However, since HSUPA can support soft handover in uplink, support on the network is required.

3 is a diagram illustrating a change in the MAC layer according to the introduction of the HSDPA technology and HSUPA technology in the present invention.

Referring to FIG. 3, in the conventional WCDMA R99, a MAC-d sublayer controlling a dedicated transport channel is used, but when HSDPA is additionally supported, a MAC-hs sublayer is added thereto, and when HSUPA is supported, MAC-e is used. And MAC-es sublayers are added respectively.

The newly added MAC layer has different positions depending on its role. Note that the MAC-hs and MAC-e sublayers are located on Node B (base station) and the MAC-es are located on RNC (base station controller). There is. For reference, the reason why the MAC-es sublayer supporting HSUPA is located in the RNC is that HSUPA supports uplink soft handover.

4 is a diagram illustrating a MAC-hs sublayer structure of UTRAN used as an example of the present invention.

The MAC-hs sublayer of UTRAN contains most of the functionality associated with HSDPA. In particular, a scheduling function for determining a data transmission order and a HARQ function for increasing transmission efficiency are included. Since the MAC-hs sublayer can be shared by all terminals, only one entity is defined per base station.

Referring to FIG. 4, the uppermost flow control function prevents data loss due to congestion of the network in consideration of the transmission capability of the interface.

Data transmitted from the RNC is stored in a buffer of the MAC-hs, and several buffers are provided in the MAC-hs. Each buffer is called Priority Queue and is divided according to logical channel priority. Up to 8 Priority Queues can be created. If there are multiple logical channels with the same priority, the data transferred from them is stored in the same queue. This function of distributing data to the appropriate Priority Queue according to the priority of data is called Priority Queue Distribution.

The transmission order of data stored in each queue is decided by scheduler's decision. Multiple packets stacked in a queue can be bundled and transmitted. If they are in the same queue, data from different logical channels can be bundled together. The basic transmission unit of the bundled data is called a MAC-hs PDU. When the scheduler determines the appropriate queue and data size, it configures the MAC-hs PDU and transmits it to the terminal through the HARQ function.

In FIG. 4, a plurality of HARQ processes exist in the HARQ entity to transmit each MAC-hs PDU by a stop-and-wait method. That is, the MAC-hs PDU delivered to the HARQ Entity is allocated to the appropriate HARQ process, and this HARQ process repeats the transmission until the corresponding MAC-hs PDU successfully delivers and, if successfully delivered, delivers another MAC-hs PDU. Take it and send it to the terminal.

5 is a diagram illustrating a structure of a receiving side MAC-hs sublayer of a terminal used as an example of the present invention.

Referring to FIG. 5, the MAC-hs sublayer located in the terminal recovers data received through the HS-DSCH and transfers the data to the upper MAC-d sublayer.

Data received by the HS-PDSCH through the HARQ function of the base station (MAC-hs PDU) is subjected to a decoding process in the HARQ entity of the terminal. First, when the terminal receives the MAC-hs PDU is assigned to the appropriate HARQ process according to the HARQ process number included in the HS-SCCH. When the MAC-hs PDU is successfully recovered, this data is stored in the appropriate buffer, which is called the Reordering Queue. This reordering queue is a storage space corresponding to the priority queue of the base station and stores data having the same priority. The terminal may store data in the appropriate reordering queue by referring to the queue ID included in the header information of the MAC-hs PDU. The function of distributing the received MAC-hs PDUs to the appropriate Reordering Queue according to the priority is called Reordering Queue Distribution.

The function of extracting the MAC-d PDU (= MAC-hs SDU) from the MAC-hs PDU when transferring the data stored in the buffer to the upper layer is called disassembly.

6 is a diagram illustrating the structure of a MAC-hs PDU used as an example of the present invention.

Referring to FIG. 6, a basic data unit transmitted and received between a base station and a terminal on a MAC-hs sublayer is a MAC-hs PDU. MAC-hs SDUs (= MAC-d PDUs) delivered from the MAC-d sublayer may be bundled together to form a MAC-hs PDU, and in some cases, data transmitted from different logical channels may have the same MAC-hs May be included in the PDU.

The MAC-hs PDU is divided into a header information and a payload which is a data part. The payload includes MAC-hs SDUs as user data, and the header includes information for identifying MAC-hs SDUs included in the payload.

The VF (Version Flag) is included in front of the header. This information is 1 bit, but it doesn't contain much information. The UE informs that the MAC-hs PDU structure used is simply for HSDPA. Therefore, always set it to '0'.

The following header information is a Queue ID. As can be seen from the MAC-hs structure of the base station, a plurality of priority queues for data transmission are provided in the MAC-hs sublayer, and a queue ID is used as information for identifying each priority queue. Since it consists of 3 bits, the base station can configure up to 8 priority queues, and the terminal finds the appropriate reordering queue based on this information and stores the data.

Subsequent header information is a TSN (Transmission Sequence Number) used as a serial number indicating the transmission order of each MAC-hs PDU in the same queue. The sender increments the value by 1 and adds it to the header information of the MAC-hs PDU.

The following {SID, N, F}, three make up a combination. SID (Size Index Identifier) indicates the size of the MAC-d PDU included in the MAC-hs PDU. However, the size of the MAC-d PDU is not explicitly indicated, and the size is inferred through the mapping relationship between the MAC-d PDU size and the SID predetermined by the RRC. And, N (Number of MAC-d PDU) field indicates the consecutive number of MAC-d PDU having the size of the SID.

If data transmitted from other logical channels are multiplexed together in a MAC-hs PDU, the F (Flag) field may be used to indicate the presence of additional {SID, N, F}.

The payload shown in FIG. 6 is composed of MAC-d PDUs transmitted from various logical channels. In other words, the MAC-hs PDU may consist of MAC-d PDUs stored in the same Priority Queue and may also include MAC-d PDUs transmitted from different logical channels. However, data delivered from the same logical channel must be continued in the MAC-hs PDU. In addition, if the payload of the MAC-hs PDU cannot be filled with the MAC-d PDU, padding information having no meaning may be added to the remaining part. Since the effective payload size can be inferred by the combination of {SID, N}, the extraction of the MAC-d PDU is not affected by the addition of the padding information.

7 is a diagram illustrating a structure of a MAC-es / MAC-e sublayer of a terminal for supporting HSUPA as an example of the present invention.

Referring to FIG. 7, since the MAC-es is a function for supporting soft handover in the UTRAN, the terminal does not treat the MAC-es separately from the MAC-e sublayer. However, logically, a plurality of MAC-d PDUs transmitted from the upper layer form a MAC-es PDU, and several of these MAC-es PDUs form a MAC-e PDU.

MAC-d PDUs delivered from the upper layer (MAC-d sublayer) of the terminal are first stored in an appropriate buffer of the MAC-es / e sublayer. One buffer is provided for each logical channel, and one buffer is provided for each logical channel in the Multiplexing and TSN Setting block. Transmission of each MAC-e PDU is performed by a plurality of HARQ processes existing within the HARQ entity, and each HARQ process transmits data to the base station while operating in a stop-and-wait manner.

The basic unit of data transmitted in the HARQ process is a MAC-e PDU and may include data transmitted from different logical channels. That is, MAC-es PDUs are formed by grouping MAC-d PDUs delivered from each logical channel, and a plurality of MAC-es PDUs are collected to form a MAC-e PDU. In this case, when a MAC-es PDU is configured from a plurality of MAC-d PDUs stored in each buffer, a transmission sequence number (TSN) is added to a header of the MAC-es PDU in order to store data sequentially in the receiving buffer.

The E-TFC Selection function configures a MAC-e PDU suitable for uplink transmission. The terminal determines the maximum transmission rate that can be sent based on the scheduling information received from the base station, and attempts transmission within the range without departing from the level.

Unlike the terminal, the internal structure of the MAC-es / MAC-e sublayer in the UTRAN is distributed to the base station and the RNC so that each sublayer can be separated.

8 is a diagram illustrating an internal structure of a MAC-e sublayer located in a base station.

Referring to FIG. 8, the MAC-e PDU delivered through the HARQ process of the terminal is allocated to the appropriate HARQ process inside the HARQ entity of the base station and decoded.

If the MAC-e PDU is successfully received, it separates the MAC-es PDU for each logical channel and delivers it to the MAC-es sublayer located in the RNC. Since there is no separate buffer in the MAC-e sublayer, MAC-e PDUs successfully recovered in the HARQ process are delivered to the MAC-es sublayer upon recovery.

A function indicated by a dotted line in FIG. 8 is a function of generating scheduling information transmitted in downlink in order to control an uplink transmission rate of HSUPA. This information plays a very important role in uplink traffic control, but since the standard specification does not define a detailed generation algorithm for this, each system manufacturer can generate optimal scheduling information unique to each system manufacturer.

9 is a diagram illustrating an internal structure of a MAC-es sublayer located in an RNC.

Referring to FIG. 9, since a soft handover for uplink is assumed, a process of transmitting data from several base stations can be seen. MAC-es PDUs delivered to MAC-es of the RNC are classified by logical channels and stored in the reordering queue. Since the same data may be delivered from several base stations, if the same MAC-es PDU is delivered, only one is selected and stored in the reordering queue. This function is called macro diversity and is represented by Combining in FIG.

When passing data to the upper layer, passing the Disassembly function removes the header of the MAC-es PDU and separates each MAC-d PDU.

10 is a diagram showing the structure of a MAC-es PDU used in the present invention.

Referring to FIG. 10, MAC-d PDUs (= MAC-es SDUs) stored for each logical channel constitute a payload of the MAC-es PDU by the E-TFC Selection function. At this time, TSN is attached at the forefront to inform the sequence number of each payload. Configuration information of the MAC-es PDU is known through the DDI and N fields. This information is not directly added to the MAC-es payload. First, the data description indicator (DDI) is composed of 6 bits and includes MAC-d flow identification information, logical channel identification information, and index information for knowing the size of the MAC-d PDU to which the corresponding payload belongs. Therefore, various information of the MAC-d PDU can be inferred through the DDI information. The N field indicates the number of consecutive MAC-d PDUs having the same DDI value.

MAC-es PDUs configured for each logical channel are combined again to form one MAC-e PDU. This process is shown in FIG. 11 is a diagram illustrating a process of configuring MAC-e PDUs by MAC-es PDUs according to the present invention. As can be seen in FIG. 11, it can be seen that {DDI, N} fields, which are not included in the process of configuring the MAC-es PDU, are gathered together and used as header information of the MAC-e PDU.

When the payload of the MAC-e PDU cannot be filled with the MAC-es PDU, padding information having no meaning may be used. In some cases, SI (Scheduling Information) information for informing the base station of the terminal information may be included in the padding information part. SI information is not always transmitted when transmitting the MAC-e PDU and is included only when it is necessary to inform the base station of the status information of the terminal.

12 is a block diagram schematically showing the configuration of a receiving packet processing apparatus for a real-time service according to an embodiment of the present invention.

Referring to FIG. 12, the apparatus for receiving a packet according to the present invention includes a physical layer unit 1210, a MAC layer unit 1220, an RLC layer unit 1230, and an upper layer unit 1240.

The physical layer unit 1210 receives packet data through a wireless channel.

The MAC layer unit 1210 receives the MAC PDU successfully received from the physical layer unit 1210, requests retransmission for an error packet, does not wait even if a previous packet is not received, and is successfully received. The MAC PDU is immediately delivered to the RLC layer unit 1230.

In addition, the MAC layer 1210 may be a MAC-hs sublayer supporting HSDPA technology or a MAC-es sublayer supporting HSUPA technology.

In addition, the MAC layer unit 1210 immediately transfers the payload of the successfully received MAC PDU to the RLC layer unit 1230 in case of a real-time service. In this case, the real time service may be an example of a voice service.

When the MAC layer unit 1210 receives the MAC PDU successfully received for the packet data from the physical layer unit 1210 in case of a non-real-time service, the MAC layer unit 1210 only receives the MAC PDU when all previous packets are successfully received. The payload of the controller is transferred to the RLC layer unit 1230.

The RLC layer unit 1230 receives the RLC PDU from the MAC layer unit 1220 and configures the RLC SDU to the upper layer unit 1240.

In addition, the RLC layer unit 1230 is configured as an RLC SDU through retransmission and payload concatenation / split for the RLC PDU received from the MAC layer unit 1220.

The upper layer unit 1240 receives the RLC SDU from the RLC layer unit 1230 and delivers the RLC SDU to another layer or another node.

In addition, the upper layer unit 1240 stores the MAC SDU and delivers the packet to another upper layer or another network node according to the transmission time of the real-time service.

In addition, when the upper layer unit 1240 receives the RLC SDU from the RLC layer unit 1230, the upper layer unit 1240 discards the packets.

13 is a flowchart illustrating a method of processing a received packet according to an embodiment of the present invention.

Referring to FIG. 13, the physical layer unit 1210 receives packet data through a wireless channel and transmits the packet data to the MAC layer unit 1220 (S1310).

Subsequently, in the state where the MAC layer unit 1220 receives the MAC PDU successfully received from the physical layer unit 1210, in case of a real-time service (S1320-Yes), the MAC layer unit 1220 immediately transmits the RLC PDU even if the MAC PDUs are not sequentially delivered. The transfer to the RLC layer unit 1230 (S1322).

In this case, the MAC layer 1220 is implemented as a MAC-hs sublayer supporting HSDPA technology or a MAC-es sublayer supporting HSUPA technology.

In the present invention, when the real-time service is supported through the HSDPA / HSUPA, the MAC-hs PDU or MAC-es PDU successfully received by the MAC layer unit 1220 is immediately transmitted to the RLC layer unit 1230 even if a previous packet does not arrive. To pass.

Subsequently, the RLC layer unit 1230 receives the RLC PDU successfully received from the MAC layer unit 1220 and recovers the RLC SDU through the retransmission and payload concatenation / splitting to the upper layer unit 1240. S1324).

Subsequently, the upper layer unit 1240 transfers the RLC SDU received from the RLC layer unit 1230 to another layer or another node (1326).

That is, the upper layer unit 1240 stores the received RLC SDU and delivers the packet to another upper layer or another network node according to the transmission time of the real-time service.

At this time, when the upper layer unit 1240 receives the RLC SDU from the RLC layer unit 1230, the upper layer unit 1240 discards the corresponding packets.

Subsequently, if the service ends (S1330-Yes), the operation ends, and if not (S1330-No), the process returns to step S1310 described above, and the physical layer unit 1210 receives the packet data through the wireless channel to the MAC layer. It is repeated from the process to deliver to the unit 1220.

On the other hand, the MAC layer unit 1220 stores the RLC PDU in the reordering buffer in the case of non-real-time service (S1320-No) while receiving the MAC PDU successfully received from the physical layer unit 1210 (S1340). .

Subsequently, the MAC layer unit 1220 transfers the sequentially arrived RLC PDUs to the RLC layer unit 1230 (S1342).

In addition, when the MAC layer unit 1220 receives the MAC PDU successfully received from the physical layer unit 1210 in case of a non-real-time service, the MAC layer unit 1220 performs a payload of the MAC PDU only when all previous MAC PDUs are successfully received. Transfer to RLC layer 1230.

Subsequently, the RLC layer unit 1230 configures an RLC SDU and transmits it to the higher layer unit 1240 (S1344).

If the service is terminated (S1330-Yes), the operation ends and if it is not terminated (S1330-No), the process returns to the above-described step S1310.

14 is a diagram illustrating a data processing performed by a MAC layer unit according to an embodiment of the present invention.

In general, since the real-time service is sensitive to delay time, a value of data may be lost when a retransmission process performed by the RLC layer unit 1230 is performed. Therefore, most real-time services operate in Unacknowledged Mode (UM) RLC, a mode that does not support retransmission. The existing UM RLC layer assumes that previous packets of RLC PDUs that have not arrived sequentially are in error and immediately discard the associated RLC SDUs. However, in the present invention with reference to FIG. 14, the recovered RLC SDU is transmitted to the upper layer unit 1240 regardless of whether the RLC PDU is sequential, and the upper layer unit 1240 is transferred to another layer or another network node at an appropriate time. To pass.

In the conventional MAC layer unit, it is necessary to wait until all previous MAC PDUs are sequentially received, but in the present invention, the successfully received MAC PDUs are immediately delivered to the RLC layer unit 1230. In FIG. 14, the MAC PDU having TSN = 4 is immediately transmitted to the RLC layer unit 1230, which is a higher layer, regardless of whether the MAC PDU having TSN = 3 is received. The MAC PDU with TSN = 4 includes two RLC PDUs, which in turn include four RLC SDUs. Among the RLC SDUs delivered to the RLC layer unit 1230, information that can be delivered to the upper layer unit 1240 without being split is RLC SDU2 and RLC SDU3, so the RLC SDUs are recovered through the concatenation / division process of the RLC layer. After that, it is transferred to the upper layer unit 1240. The upper layer unit 1240 delivers the packet to another layer or another network node in accordance with a reproduction time point (terminal side) or a packet transmission time point (network side) of the real time service.

After the MAC PDU having TSN = 4 is delivered to the RLC layer unit 1230, when a MAC PDU having TSN = 3 is received, it is immediately delivered to the RLC layer unit 1230 to configure the RLC SDU1 and then to the upper layer unit 1240. do. The upper layer unit 1240 checks the validity of the RLC SDU1, and if the transmission of the corresponding information is valid, the reproduction or transmission is completed at an appropriate time. If RLC SDU2 or RLC SDU3 has already been sent when RLC SDU1 arrives at the upper layer, then RLC SDU1 is discarded because it has no value as data.

As described above, according to the present invention, when MAC PDUs are received out of order in the MAC layer through a radio channel in a receiving apparatus of an HSUPA system or an HSDPA system, the apparatus waits until all previous MAC PDUs are received. Real time-sensitive real-time delay by delivering to RLC layer without delay and incomplete re-transmission of RLC SDU in RLC layer. A received packet processing method and apparatus capable of preventing loss of received packets in a service can be realized.

As those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features, the embodiments described above should be understood as illustrative and not restrictive in all aspects. Should be. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

The present invention can be applied to a high-speed wireless communication system supporting real-time services using HSDPA / HSUPA technology.

In addition, the present invention can be applied to a service or a communication system requiring a technology capable of preventing the loss of a received packet in a delay-sensitive real-time service.

The present invention can be applied to a packet receiving apparatus of a high speed wireless communication system including a physical layer, a MAC layer, an RLC layer, and an upper layer.

1200: receiving packet processing apparatus 1210: physical layer portion
1220: MAC layer portion 1230: RLC layer portion
1240: higher hierarchy

Claims (18)

In the received packet processing apparatus using HSUPA / HSDPA technology, which is a high-speed wireless communication system,
A physical layer unit for receiving packet data through a wireless channel;
Receive a medium access control (MAC) Packet Data Unit (PDU) successfully received from the physical layer unit, request retransmission of an errored MAC PDU, and even if the MAC PDU is not sequentially transmitted, the successfully received MAC A MAC layer unit for delivering a Radio Link Control (RLC) PDU included in the PDU to a next RLC layer unit; And
An RLC layer unit configured to receive the RLC PDU from the MAC layer unit, form an RLC SDU (Service Data Unit), and deliver the RLC PDU to a next higher layer unit;
Receive packet processing apparatus comprising a. The method of claim 1,
An upper layer unit which receives the RLC SDU from the RLC layer unit and delivers the RLC SDU to another layer or another node;
Receive packet processing apparatus further comprises. The method of claim 1,
The MAC layer unit is a MAC-hs sub-layer unit supporting the HSDPA technology or MAC-es sub-layer unit supporting the HSUPA technology, characterized in that the packet processing apparatus. The method of claim 1,
The MAC layer unit, in the case of a real-time service, the packet receiving apparatus, characterized in that for immediately delivering the RLC PDU to the RLC layer unit. The method of claim 4, wherein
And the real time service comprises a voice service. The method of claim 1,
The RLC layer unit is configured to configure the RLC SDU through the retransmission and payload concatenation / split for the RLC PDU received from the MAC layer unit. The method of claim 1,
And the upper layer unit stores the RLC SDU and delivers the packet to another upper layer or another network node in accordance with a transmission time of a real-time service. The method of claim 1,
The upper layer unit, when receiving the RLC SDU from the RLC layer unit, the received packet processing apparatus, characterized in that for discarding the packets if the transmission time has passed. The method of claim 1,
In case of a non-real-time service, the MAC layer unit delivers the payload of the MAC PDU to the RLC layer unit only when all previous packets are successfully received when the MAC PDU is successfully received from the physical layer unit. Receive packet processing apparatus, characterized in that. A method of processing a received packet by a device including a physical layer unit, a MAC layer unit, an RLC layer unit, and a higher layer unit,
(a) receiving, by the physical layer unit, packet data through a wireless channel;
(b) The MAC layer receives the MAC PDU successfully received from the physical layer unit, and immediately delivers the RLC PDU, which is a payload of the successfully received MAC PDU, to the RLC layer even though the MAC PDUs are not sequentially delivered. Doing;
(c) the RLC layer receiving the successfully received RLC PDU from the MAC layer unit and configuring the RLC SDU to deliver to the upper layer unit; And
(d) receiving the RLC SDU from the RLC layer unit by the upper layer unit and transferring the RLC SDU to another layer or another node;
Receive packet processing method comprising a. The method of claim 10,
In the step (b), the received packet processing method, characterized in that for requesting retransmission for the packet in error of the received packet data. The method of claim 10,
The step (b) is performed by the MAC-hs sublayer supporting HSDPA technology or the MAC-es sublayer supporting HSUPA technology. The method of claim 10,
In the step (b), in the case of a real-time service, a method of processing a received packet, wherein the payload of the successfully received MAC PDU is immediately transmitted to the RLC layer unit. The method of claim 13,
And the real time service comprises a voice service. The method of claim 10,
In the step (c), the RLC PDU received from the MAC layer unit may be generated as the RLC SDU through retransmission and payload concatenation / division and delivered to the upper layer unit. The method of claim 10,
In the step (d), the method stores the RLC SDU and delivers the packet to another upper layer or another network node according to a transmission time of a real-time service. The method of claim 10,
In the step (d), when the transmission time passes when the RLC SDU is received from the RLC layer unit, the corresponding packet is discarded, wherein the corresponding packets are discarded. The method of claim 10,
In step (b), in case of a non-real-time service, when the MAC PDU received successfully from the physical layer unit is delivered, the payload of the MAC PDU is transmitted to the RLC layer unit only when all previous packets are successfully received. Receive packet processing method characterized in that the forwarding.

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