WO2010102425A1

WO2010102425A1 - Evolved-multimedia broadcast multicast service packet transmission method, gateway and base station

Info

Publication number: WO2010102425A1
Application number: PCT/CN2009/000271
Authority: WO
Inventors: 陈宇; 王河; 汪勇刚
Original assignee: 上海贝尔股份有限公司; 阿尔卡特朗讯
Priority date: 2009-03-13
Filing date: 2009-03-13
Publication date: 2010-09-16
Also published as: CN102301672B; CN102301672A

Abstract

The present invention provides an Evolved-Multimedia Broadcast Multicast Service (E-MBMS) packet transmission method, a gateway and a base station for implementing the packet transmission method. According to an aspect of the invention, Media Access Control (MAC) sub header is added at the beginning of the last MAC Packet Data Unit (PDU) bearing a MBMS service in each schedule period, and the number of the MAC sub headers equals to the number of the services locating at the end of the MAC PDU; however, the transparent mode of MAC sub header is adopted at the beginning of other MAC PDUs, that is, no MAC sub header is added.

Description

Evolved multimedia broadcast multicast service packet transmission method,

Gateway and base station

The present invention relates to the field of mobile communications, and more particularly to an evolved multimedia broadcast multicast service (E-MBMS service) packet transmission method, and a gateway and a base station implementing the packet transmission method. Background technique

In 3GPP R9, a specific support scheme for Evolved Multimedia Broadcast Multicast Service (E-MBMS) will be provided. An important issue with E-MBMS is how to support statistical multiplexing, which has been found to have an impact on efficiency and synchronization. It is still unclear whether to use a separate synchronous (SYNC) entity or a shared SYNC entity (this is also a problem that 3GPP needs to address in the specific implementation process). In order to improve the efficiency of wireless resource utilization and ensure synchronization, it is necessary to adapt/modify the current Media Access Control (MAC) / Radio Link Control (RLC) protocol. The present invention discloses a technical solution suitable for sharing a SYNC entity, but the present invention can also achieve less overhead for an independent SYNC entity structure.

In particular, Figure 1A shows a schematic diagram of a U-plane architecture for MBMS content synchronization, and Figure 1B shows the logical architecture of E-MBMS.

Statistical multiplexing is the purpose of multiplexing multiple MBMS services to save resources. Currently 3GPP has decided to support this technology. Statistical multiplexing discards the way in which each service in the previous version of the protocol allocates fixed resources, but multiple services reuse and share the same resource, realizing the complementary resources between multiple services by real-time changes in the bit rate of the service itself. Thereby reducing the total resource requirements. When performing statistical multiplexing, each service is serially multiplexed in the base station to the MAC PDU generated by the same MAC entity, but each service still has its own RLC entity. Therefore, although statistical multiplexing is similar to treating multiple services as one service transmission, different services are ultimately distinguished, so different services are carried on different RLC PDUs. The order of service multiplexing is determined in advance by the central control entity MCE (MBMS Coordination Entity) of the MBMS and informed to the base station (refer to FIG. 1B). On the other hand, in order to support single-frequency network (SFN) transmission, the MBMS service needs to synchronize data between base stations. The method is to add a synchronization (SYNC) entity from the gateway to the base station (refer to Figure 1A). The data encapsulated by this SYNC entity provides information such as number, byte count, packet count, and so on. In this way, when a certain base station loses one or more data packets, the size of the lost packet can be known according to the number, byte count, and packet count in the subsequently received data packet, and the exact time at which the transmission is resumed is determined. However, when multiple services are multiplexed together, it is not enough to know only the above information, because the MAC sub-header and the RLC header added for different services at the time of multiplexing are different from each other according to different situations. Therefore, it is also necessary to modify the current MAC RLC protocol so that the base station can still use the information provided above (number, byte count, packet count) to determine the exact moment to resume transmission.

More specifically, Fig. 1C is a diagram showing an example of packet transmission from the gateway 100 to the base stations 201 to 203.

As shown in FIG. 1C, the gateway 100 receives service packets of different E-MBMS services, and forwards the service packets to different base stations (eNBs) 201-203 through IP multicast. In the base stations 201 to 203, the services of these different E-MBMS services are multiplexed together at the MAC layer. The base stations 201 to 203 use a single frequency network (FSN) technology to transmit MBMS signals, which has the advantage that signals from different base stations 201 to 203 mutually benefit rather than interfere with each other. SFN technology requires fairly strict synchronization. However, during IP multicast transmissions from gateway 100 to base stations 201 ~ 203, packets may be lost or experience different delays. Therefore, the SYNC protocol is required.

Although the specific details of the SYNC protocol have not been determined so far, the main content of the SYNC protocol has been clarified, including byte count information and packet count information. If the service is not multiplexed, the SYNC protocol can work properly with the existing MAC/RLC protocol; however, if multiple services are multiplexed together, some uncertainty may cause the network to be corrupted. Below, the above uncertainty issues will be discussed in detail.

On the one hand, for multi-cell SFN transmission, there is no retransmission mechanism, and the MBMS scheme adopts a special control/scheduling method, so some fields in the existing MAC/RLC protocol are unnecessary, so these fields can be omitted. On the other hand, a shared SYNC entity can be used (in this case, the Ml interface can be simpler). In this case, the byte count and packet count are for the SYNC entity, indicating the total number of bytes and the total number of packets for all services sharing the SYNC entity. But there is still a problem with this. FIG. 2A is a diagram for explaining the base station 202 parsing a packet loss situation. For example, as shown in FIG. 2A, it is assumed that four packets belonging to three different services (Service 1 to Service 3) are lost during transmission from the gateway 100 to the base station 202 (four RLC Service Data Packets (SDUs)) . The base station 202 can know that four packets are lost by the packet counting information carried by the next correct packet, and can also know how many bytes are lost by the next byte counting information. The problem is that the base station 202 does not know how the lost packets are multiplexed together, and the size of the MAC/RLC header will vary depending on the multiplexing situation.

2B to 2D show the structure of the MAC sub-header, the RLC header fixed part, and the RLC header extension, respectively.

According to the prior art, the MAC data transmitted in each slot of the physical layer constitutes a transport block (TB). Usually, one MAC packet data unit (PDU) constitutes one TB. Each MAC PDU can contain several MAC Service Data Units (SDUs). Each MAC SDU is an RLC Packet Data Unit (PDU). Each RLC PDU can in turn contain several RLC SDUs. The MAC sub-header is located at the beginning of each MAC PDU, the RLC header is located at the beginning of each RLC PDU, and each RLC header contains an RLC header fixed part. How many RLC SDUs are included in the RLC PDU, how many RLC header extensions are included in the RLC header, and the RLC header extension is followed by the fixed part of the RLC header.

In Figures 2B to 2D, the meanings of the abbreviations are as follows:

R: reserved bits

E: extension bit, whether there are other fields after the identifier

LCID: Logical channel identifier

F: format bit, indicating the length of L

L: length of the MAC SDU

R1 : reserved bits

FI : Frame information indicating whether an RLC SDU has segmentation at the beginning or end of the RLC PDU.

SN: serial number

LI : length indication

As shown in Figure 2A, for the same loss of three transport blocks (TB) (the dotted box in Figure 2k) In the case of the three transport blocks shown, the base station 202 may interpret this as three different scenarios as shown by (a) ~ (c) in Figure 2A, including three, four or five MAC headers, respectively. . For convenience of description, it is assumed that the solid shaded portion located at the far right in FIG. 2A is padding data - (padd ing); if the solid shaded portion represents business data, the corresponding field needs to be added in the corresponding ^1 header, but The problems set forth in the present invention are not affected. Based on the above assumptions, RLD SDU 4 is the last SDU of Service 3 in the current scheduling period. The same assumptions apply to FIGS. 4A, 4B, and 6 shown and described later. According to (a) in Fig. 2A,

The first TB consists of a MAC PDU consisting of an RLC.

A PDU is formed. The RLC PDU includes only one RLC SDU (RLC SDU 1 ). Therefore, at the beginning of the first TB, a MAC sub-header, an RLC header fixed part, and an RLC header extension part are included;

The second TB consists of a MAC PDU consisting of one RLC PDU containing two RLC SDUs (RLC SDU 2 and RLC)

SDU 3), therefore, at the beginning of the second TB, includes a MAC sub-header, an RLC header fixed part, and two RLC header extensions;

The third TB is composed of a MAC PDU consisting of one RLC PDU, the RLC PDU containing only one RLC SDU (RLC SDU 4 ), and therefore, at the beginning of the third TB, a MAC sub-header is included. One

RLC header fixed part and an RLC header extension part;

According to (b) in Figure 2A,

The first TB is composed of a MAC PDU consisting of one RLC PDU, the RLC PDU containing only one RLC SDU (RLC SDU 1 ), and therefore, at the beginning of the first TB, a MAC sub-header is included. One

RLC header fixed part and an RLC header extension part;

The second TB is composed of a MAC PDU consisting of one RLC PDU, the RLC PDU containing only one RLC SDU (RLC SDU 2 ), and therefore, at the beginning of the second TB, a MAC sub-header is included. An RLC header fixed part and an RLC header extension part; The third TB consists of one MAC PDU consisting of two RLC PDUs, and each RLC PDU contains only one RLC SDU (RLC SDU 3 and RLC SDU 4), so at the beginning of the third TB, Included two MAC sub-headers, one RLC header fixed part and one RLC header extension part, and at the beginning of the second RLC PDU, an RLC header fixed part and an RLC header extension part are included;

According to (c) in Figure 2A,

The first TB consists of a MAC PDU consisting of two RLC PDUs, and each RLC PDU contains only one RLC SDU (RLC SDU 1 and RLC SDU 2 ), so at the beginning of the first TB, Contains two

A MAC sub-header, an RLC header fixed part, and an RLC header extension part, and at the beginning of the second RLC PDU, include an RLC header fixed part and an RLC header extension part;

The second TB consists of one MAC PDU, which contains two RLC PDUs, and each RLC PDU contains only one RLC SDU ( RLC SDU)

3 and RLC SDU 4), where RLC SDU 4 also extends to the third TB, therefore, at the beginning of the first TB, ie at the beginning of the first RLC PDU, contains two MAC sub-headers, one RLC header a fixed part and an RLC header extension, and at the beginning of the second RLC PDU, an RL (^ 固定 fixed part;

The third TB consists of a MAC PDU consisting of an RLC PDU containing only one RLC SDU (part of the RLC SDU 4), so at the beginning of the first TB, the packet is ^^ A MAC sub-header, an RLC header fixed part, and an RLC header extension. Therefore, if the base station 202 adds the MAC/RLC header according to one of (a) to (c) in FIG. 2A, since the base station 202 itself may erroneously analyze the situation of the lost TB, the added MAC/RLC header is different. The MAC/RLC headers added by the other base stations 201 and 203 cause the length of the entire data to be different (the right side of the RLC SDU 4 is not aligned), and the base stations 201 to 203 cannot resynchronize at a common starting point. Therefore, unless the base station 20 ² knows With the exact reuse scheme, synchronization will be compromised.

According to the prior art, when each RLC SDU has a length indication (LI), there is no problem of uncertainty for the RLC header extension. Therefore, the problem of the present invention is the uncertainty of the fixed portion of the MAC sub-header and the RLC header. Summary of the invention

In view of the above problems, the present invention proposes an evolved multimedia broadcast multicast service (E-MBMS service) packet transmission method, and a gateway and a base station implementing the packet transmission method. According to a first aspect of the present invention, an E-MBMS service packet transmission method is provided, including: adding a MAC sub-header and a MAC sub-header at the beginning of a last MAC PDU carrying an MBMS service in each scheduling period The number of services is equal to the number of services in the last position in the MAC PDU; at the beginning of other MAC PDUs, no MAC sub-header is added.

Preferably, the E-MBMS service packet transmission method further includes: adding an RLC header fixed part at the beginning of the RLC PDU.

Preferably, the E-MBMS service packet transmission method further includes: adding a fixed part and an extension part at the beginning of the RLC PDU where the last segment of one RLC SDU carrying one MBMS service is located in each scheduling period RLC header; and at the beginning of other RLC PDUs, no RLC ^ header is added. According to a second aspect of the present invention, an E-MBMS service packet transmission method is provided, including: adding an evolved MAC sub-header and a MAC sub-header at the beginning of a last MAC PDU carrying an MBMS service in each scheduling period And the number of MAC sub-headers is equal to the number of services in the last position of the MAC PDU; at the beginning of other MAC PDUs, the evolved MAC sub-^ is added.

Preferably, the E-MBMS service packet transmission method further includes: at the beginning of the RLC PDU, no RL is added, that is, the transparent RLC mode is adopted.

Preferably, the E-MBMS service packet transmission method further includes: in each scheduling In the period, the RLC header of the last segment of an RLC SDU carrying one MBMS service is added, and the RLC header of the extended part is added, that is, the non-feedback RLC mode is adopted; and at the beginning of other RLC SDUs, the RLC header is not added. That is, the transparent RLC mode is adopted.

Preferably, the format of the evolved MAC sub-header is R/R/E/LCID, where R represents a reserved bit, E represents an extended bit, and LCID represents a logical channel identifier. More preferably, a reserved bit R in the evolved MAC sub-header is enabled to indicate whether a transparent RLC mode or a no-feedback RLC mode is employed. According to a third aspect of the present invention, an E-MBMS service packet transmission method is provided, comprising: receiving an IP data packet carrying an MBMS service; and when receiving the IP data packet correctly, according to the first or the first according to the present invention The E-MBMS service packet transmission method according to the second aspect, forming a TB that carries the MBMS service; and transmitting the generated TB to the UE.

Preferably, the E-MBMS service packet transmission method further includes: according to the total number of multiplexed MBMS services and the packet count, in accordance with the first or second scheme according to the present invention, in the case of an error in the reception-receive error The E-MBMS service packet transmission method determines the number of fixed parts of the MAC sub-header and the RLC header; according to the determined number of fixed positions of the MAC sub-header and the RLC header, it is determined that other base stations that have not received a reception error occur The transmission time of the transmission data to be generated by the data packet processing and the header insertion processing performed by the erroneous IP data packet; and the silence during the determined transmission duration to maintain strictness between the respective base stations receiving the MBMS service Synchronize. According to a fourth aspect of the present invention, a base station is provided, including: a MAC sub-header insertion unit, configured to add a MAC sub-header and a MAC in the beginning of a last MAC PDU carrying an MBMS service in each scheduling period. The number of sub-headers is equal to the number of services in the last position of the MAC PDU, and at the beginning of other MAC PDUs, no MAC sub-header is added.

Preferably, at the beginning of the RLC PDU, no RL is added.

Preferably, the base station further includes: an RLC header insertion unit, configured to add a fixed part and an extended part at the beginning of the RLC PDU where the last segment of an RLC SDU carrying one MBMS service is located in each scheduling period RLC header, as well as in it At the beginning of his RLC PDU, no RLC header is added. According to a fifth aspect of the present invention, a base station is provided, including: a MAC sub-header insertion unit, which adds an evolved MAC sub-header and a MAC sub-header at the beginning of the last MAC PDU carrying an MBMS service in each scheduling period. And the number of MAC sub-headers is equal to the number of services in the last position of the MAC PDU, and at the beginning of other MAC PDUs, the evolved MAC sub-header is added.

Preferably, at the beginning of the RLC PDU, the RLC ^ 固定 fixed portion is not added, that is, the transparent RLC mode is adopted. Preferably, the base station further includes: an RLC header insertion unit, configured to add a fixed part and a beginning of the RLC PDU where the last segment of one RLC SDU of one MBMS service is located in each scheduling period The extended part of the RLC 4 header, that is, adopts the non-feedback RLC mode, and at the beginning of other RLC PDUs, does not add the RLC header, that is, adopts the transparent RLC mode.

Preferably, the format of the evolved MAC sub-header is R/R/E/LCID, where R represents a reserved bit, E represents an extended bit, and LCID represents a logical channel identifier. More preferably, a reserved bit R in the evolved MAC sub-header is enabled to indicate whether a transparent RLC mode or a no-feedback RLC mode is employed. According to a sixth aspect of the present invention, a base station is provided, comprising: a receiving unit, configured to receive an IP data packet carrying an MBMS service; and a TB forming unit, configured to, when receiving the IP data packet correctly, according to the present invention The E-MBMS service packet transmission method according to the first or second aspect, forming a TB that carries the MBMS service; and a transmission unit, configured to transmit the generated TB to the UE.

Preferably, the base station further includes: a header determining unit, configured to: according to the total number of multiplexed MBMS services and the packet count, in the case of a reception error, according to the first or second aspect of the present invention The E-MBMS service packet transmission method determines the number of fixed portions of the MAC sub-header and the RLC header; the transmission duration determining unit is configured to determine that no reception occurs according to the determined number of the MAC sub-header and the fixed portion of the RLC header Wrong data base packet processing performed by other base stations for IP data packets that have received errors The header insertion process processes the transmission duration of the transmission data to be generated; and a transmission control unit for controlling the transmission unit to remain silent during the determined transmission duration to maintain the base station and other base stations receiving the MBMS service Strict synchronization. The features of the invention are as follows:

1. Each transport block (TB) uses an evolved MAC header for scheduling assistance;

2. In addition, each business has a MAC ^ header;

3. A reserved bit in the MAC header is used to indicate whether the transparent mode or the no feedback mode is used;

4. In addition to the RLC PDU carrying the last segment of the RLC SDU, the RLC adopts a transparent mode;

5. The RLC fixed part or the RLC header is removed.

The advantages of the invention are:

1. Since the overhead depends only on the number of multiplexed services (semi-static) and the number of RLC SDUs (indicated by the byte count), when data loss occurs, resynchronization can be achieved;

2. The overhead is small due to the transparent mode in which the MAC sub-header is not added;

3. Applicable to independent SYNC entities and shared SYNC entities;

4. It is generally compatible with the existing unicast MAC protocol, and the modification is small. DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the Detailed Description Description

Figure 1A shows a schematic diagram of a ϋ plane architecture for MBMS content synchronization.

Figure 1B shows the logical architecture of the E-MBMS.

Fig. 1C is a diagram showing an example of packet transmission from the gateway 100 to the base stations 201 to 203.

FIG ² A is a schematic diagram for explaining a base station 202 where packet loss parsing. 2B 2D show the structure of the MAC sub-header, the RLC header fixed part, and the RLC header extension part, respectively. Figure 3 is a schematic diagram showing a scheduling period in accordance with the present invention.

Figure 4A is a diagram for explaining the analysis of packet loss conditions by the base station 202 in accordance with the present invention, in which the RLC header fixed portion is still employed.

Figure 4B is a diagram for explaining the analysis of the packet loss situation by the base station 202 according to the present invention, in which the RLC header fixed portion is completely removed, and only the RLC header extension portion is employed.

Figure 5 is a diagram for explaining an evolved MAC sub-header according to another embodiment of the present invention. 6 is a schematic diagram for explaining the parsing of a packet loss situation by the base station 202 according to the present invention, in which the evolved MAC sub-header proposed by the present invention, that is, the R/R/E/LCID header, and completely removing the RLC header fixed is used. In part, only the RLC header extension is used.

FIG. 7 is a schematic diagram showing a base station (BS or eNB) 700 for implementing the present invention. detailed description

In the following, the invention will be described in the accompanying drawings. In the following description, some specific embodiments are for illustrative purposes only and should not be construed as limiting the invention. Conventional structures or configurations will be omitted when it may result in obscuring the understanding of the present invention. Example 1

Although the base station 202 (Fig. 1C) does not know the exact multiplexing scheme, the number of multiplexed services is known. The scheduling period proposed by the present invention is as shown in FIG. Packets belonging to the same service are grouped together; different services are transmitted one by one in accordance with a predetermined transmission order; and padding data is added only after the last service. Therefore, the logical channel changes only when a service switch occurs in the transport block (TB). Therefore, a viable MAC solution is:

• In each scheduling period, the last MAC packet data unit (PDU) carrying a specific service includes a MAC sub-header, and the number of MAC sub-headers is equal to the number of services in the last position in the MAC PDU; The format of the sub-header is the same as that of FIG. 2B, and is used to indicate the length of the corresponding MAC service data unit (SDU) in the MAC PDU; • For other cases, a transparent MAC sub-header is used, ie no MAC sub-header is inserted. Since the base station 202 (Fig. 1C) can learn the number of RLC SDUs by packet counting information, a feasible RLC solution is:

• According to the RLC SDU, the RLC header including the fixed part and the extended part is used, and only the RLC header is used for the last piece of RLC SDU, that is, in each scheduling period, the last segment of an RLC SDU carrying a specific MBMS service is located. At the beginning of the RLC PDU, add Μ · 艮头;

■ The sequence number (SN) in the RLC header can be counted based on the RLC SDU or RLC PDU. If counting according to the RLC PDU, the user equipment (UE) can know how many RLC PDUs the RLC SDU can be divided according to the size of the SN, the SDU, and the size of the TB.

• For other cases, a transparent RLC header is used, ie no RLC header is inserted. Another possible RLC solution is:

• The RLC header fixed part is completely removed because Hybrid Automatic Repeat Request (HARQ) technology is not used in the Multicast Broadcast Single Frequency Network (MBSFN) scheme. Figure 4A is a diagram for explaining the analysis of packet loss conditions by the base station 202 in accordance with the present invention, in which the RLC header fixed portion is still employed. As can be seen from comparison with Fig. 2A, according to the present invention, in the case where the number of services and the number of packets included in the lost packet are known, the number of MAC sub-headers and RLC headers is determined (alignment of the right side of the RLC SDU 4;). In FIG. 4A, regardless of which of (a) to (c), the number of MAC sub-headers is three, and the number of RLC headers (the RLC header includes the RLC header fixed part and the RLC header extension part) is four. .

Figure 4B is a diagram for explaining the analysis of the packet loss situation by the base station 202 according to the present invention, in which the RLC header fixed portion is completely removed, and only the RLC header extension portion is used. As can be seen from comparison with FIG. 2A, according to the present invention, in the case where the number of services and the number of packets included in the lost packet are known, the number of fixed portions of the MAC sub-header and the RLC header is determined (aligned to the right of the RLC SDU 4). . In Fig. 4B, regardless of which of (a) to (c), the number of MAC sub-headers is three, and the number of fixed portions of the RLC header is zero.

Therefore, since the MAC sub-report included in the lost packet can be determined according to the present invention The number of fixed parts of the header and the RLC header, and according to the prior art, when each RLC SDU has one LI, the number of extension parts of the RLC header can be determined, and the base station 202 (Fig. 1C) can determine the need in case of TB loss. The length of the added MAC/RLC header, keeping its entire data length the same as that of base stations 201 and 203, still maintains synchronization between base stations 201-203. It should be noted that: In a scheduling period, the same service is continuously transmitted in time, and different services are time-division multiplexed. For a certain scheduling period, if the last data packet of a certain service is in the MAC PDU, a MAC sub-header is added at the beginning of the MAC PDU. Considering the bursty nature of the service, there may be a small amount of data for one service. For example, only 100 bits, then the 100 bits are the last data, so there may be a final data of multiple services in a MAC PDU.

The term "final" as used in this specification refers to the last data packet of a service within a scheduling period, rather than the order of the services or data within a MAC PDU. For example, in one MAC PDU in one scheduling period, 100-bit data of service 1, 200-bit data of service 2, and 300-bit data of service 3 are included, and the rest are service data of service 4 (not the last data, also That is to say, in the next immediately adjacent MAC PDU in this scheduling period, the service data of the service 4 is still included, in this case, 100 bits of the service 1 due to the continuity of the service data and the time division multiplexing between different services. The data, the 200-bit data of Service 2, and the 300-bit data of Service 3 are the last data of the respective services 1, 2, and 3. That is to say, this MAC PDU contains three services in the last position, so it is necessary to insert three MAC sub-headers at the beginning of this MAC PDU. Of course, data for services 1, 2, and/or 3 may still be included in the next scheduling period. The above specific numbers are only for the purpose of example, and the actual application may be different from the above specific numbers, but those skilled in the art can adjust themselves as needed, but such adjustment does not exceed the scope of the present invention. Example 2

If the scheduling information is not correctly received, the UE will attempt to start receiving from the first subframe until all subframes of interest are received. However, the UE wants to receive the second service but fails In the case of successfully decoding the first MAC PDU (including the MAC sub-header), the UE cannot know which MAC PDU the service of interest starts from. Therefore, additional information is required. In view of the above problems, the following improvement schemes are proposed. For specific illustration, reference may be made to FIG. 5:

• For each MAC PDU, use the R/R/E/LCID header as the first header; ■ LCID (Logica l Channe l Ident if ica t ion ) indicates the last logical channel in the MAC PDU;

■ In the case of a service switchover, the MAC header can be added twice for the last service in the MAC PDU, one of which is the above R/R/E/LCID header and the other is the normal R/R/E/ The LCID/F/L header (referred to as the normal MAC header in this specification). Even if there is no service data for a particular service, it still needs to transmit the normal MAC header of the service.

• Need to indicate which RLC mode to use, therefore, enable a reserved bit in the MAC header (shown in Figure 5 as a circle surrounded by "R,, of course, other bits of reserved bits can also be used) to indicate yes Is it transparent or not?

Feedback mode. 6 is a schematic diagram for explaining the parsing of a packet loss situation by the base station 202 according to the present invention, in which the evolved MAC sub-header proposed by the present invention, that is, the R/R/E/LCID header, and completely removing the RLC header fixed is used. In part, only the RLC header extension is used. As can be seen from comparison with FIG. 2A, according to the present invention, in the case where the number of services and the number of packets included in the lost packet are known, the number of fixed portions of the MAC sub-header and the RLC header is determined (alignment of the right side of the RLC SDU 4) . In FIG. 6, regardless of which of (a) to (c), the number of evolved MAC sub-headers is three, the number of MAC sub-headers is three, and the number of fixed portions of the RLC header is zero. According to Embodiment 2, the UB can learn whether there is a service of interest through the logical channel representation in the special MAC sub-header. Hardware implementation of the invention FIG. 7 is a schematic diagram showing a base station (BS or eNB) 700 for implementing the above technical solution of the present invention.

Specifically, referring to FIG. 7, the base station 700 includes a receiving unit 730, a transport block (TB) forming unit 740, a transmitting unit 750, a head determining unit 760, a transmission duration determining unit 770, and a transmission control unit 780.

The receiving unit 730 receives the IP data packet carrying the MBMS service.

On the one hand, upon receiving the IP data packet correctly, the TB forming unit 740 forms a TB carrying the MBMS service.

Specifically, the TB forming unit 740 may include a MAC sub-header insertion unit 710 and an RLC header insertion unit 720, the MAC sub-header insertion unit 710 performs a MAC sub-header insertion operation, and the RLC header insertion unit 720 performs an RLC header insertion operation. According to an embodiment of the present invention, the MAC sub-header insertion unit 710 adds a MAC sub-header at the beginning of the last MAC PDU carrying an MBMS service in each scheduling period, and the number of MAC sub-headers is equal to that in the MAC PDU. The number of services in the last location, and at the beginning of other MAC PDUs, does not add a MAC subheader. According to another embodiment of the present invention, the MAC sub-header insertion unit 710 adds a MAC sub-frame in the R/R/E/LCID format at the beginning of the last MAC PDU carrying an MBMS service in each scheduling period. And the MAC sub-header in the R/R/E/LCID/F/L format, and the number of MAC sub-headers in the R/R/E/LCID/F/L format is equal to the number of services in the last position in the MAC PDU, And at the beginning of other MAC PDUs, only the MAC sub-header in R/R/E/LCID format is added.

According to the present invention, the RLC header insertion unit 720 can completely remove the fixed portion of the RLC header (at the beginning of each RLC PDU), and insert the RLC header extension only at the beginning of each RLC PDU. Alternatively, the RLC header insertion unit 720 may add an RLC header including a fixed part and an extended part at the beginning of the RLC PDU where the last segment of one RLC SDU carrying an MBMS service is located, and at the beginning of other RLC PDUs, does not add RLC ^艮头.

In an embodiment employing a MAC sub-header in the .R/R/E/LCID format, one of the reserved bits R may be used to indicate whether RLC transparent mode or RLC no feedback mode is employed.

The MAC sub-header insertion unit 710 completes the MAC sub-header insertion operation and the RLC header. After the insertion unit 720 completes the RLC ^ header insertion operation, the TB formation unit 740 outputs the generated TB to the transmission unit 750.

Transmission unit 750 transmits the generated TB to the User Equipment (UE).

On the other hand, in the case where a reception error occurs (for example, due to poor transmission channel quality or excessive delay), the header determining unit 760 determines the MAC sub-portion based on the total number of multiplexed MBMS services and the packet count. The number of fixed parts of the header and RLC header.

The transmission duration determining unit 770 determines, according to the determined number of the MAC sub-header and the fixed portion of the RLC header, data packet processing and header insertion processing performed by other base stations that have not received a reception error for the IP data packet in which the reception error occurs (by The TB forming unit 740 of the other base station completes the transmission duration of the transmission data to be generated.

Transmission Control Unit 780 maintains transmission unit 750 silent during the determined transmission duration to maintain strict synchronization between base station 700 and other base stations receiving the MBMS service. For example, base station 700 can be base station 202 shown in Figure 1C; and other base stations can be base stations 201 and 203 shown in Figure 1C. .

It should be clear that the above hardware configuration is only an example of the present invention, and the above units may be adjusted according to actual needs. A plurality of units may be combined into a single execution unit according to the functions implemented thereby, or a single unit may be re-divided into a plurality of units, and any division and combination shall be regarded as a variant of the present invention, The above does not go beyond the scope of the invention.

The above examples are for illustrative purposes only and are not intended to limit the invention. It will be understood by those skilled in the art that various modifications and substitutions may be made to the embodiments without departing from the scope and spirit of the invention. In the scope.

Claims

Claim

An evolved multimedia broadcast multicast service packet transmission method, comprising: adding a multimedia access control sub-header at the beginning of a last multimedia access control packet data unit carrying a multimedia broadcast multicast service in each scheduling period And the number of multimedia access control sub-headers is equal to the number of services in the last location of the multimedia access control packet data unit;

At the beginning of other multimedia access control packet data units, no multimedia access control sub-headers are added.

2. The method for transmitting an evolved multimedia broadcast multicast service packet according to claim 1, further comprising:

At the beginning of the radio link control packet data unit, the radio link control header fixed portion is not added.

3. The method for transmitting an evolved multimedia broadcast multicast service packet according to claim 1, further comprising:

Adding a wireless chain including a fixed part and an extended part at the beginning of the radio link control packet data unit where the last segment of a radio link control service data unit carrying a multimedia broadcast multicast service is carried in each scheduling period The path control header; and at the beginning of other radio link control packet data units, no radio link control header is added.

4. An evolved multimedia broadcast multicast service packet transmission method, comprising: adding an evolved multimedia access control sub-assembly at the beginning of a last multimedia access control packet data unit carrying a multimedia broadcast multicast service in each scheduling period a header and a multimedia access control sub-header, and the number of multimedia access control sub-headers is equal to the number of services in the last location of the multimedia access control packet data unit;

At the beginning of other multimedia access control packet data units, an evolved multimedia access control sub-header is added.

5. The method for transmitting an evolved multimedia broadcast multicast service packet according to claim 4, further comprising:

No radio link control header is added at the beginning of the radio link control packet data unit The fixed part, that is, adopts the transparent wireless link control mode.

The method for transmitting an evolved multimedia or multicast broadcast multicast service packet according to claim 4, further comprising:

Adding a wireless chain including a fixed part and an extended part at the beginning of the radio link control packet data unit where the last segment of a radio link control service data unit carrying a multimedia broadcast multicast service is carried in each scheduling period The path control header, that is, the non-feedback wireless link control mode;

At the beginning of other radio link control packet data units, the radio link control header is not added, that is, the transparent radio link control mode is adopted.

The evolved multimedia broadcast multicast service packet transmission method according to any one of claims 4-6, characterized in that:

The format of the evolved multimedia access control sub-header is R/R/E/LCID, where R represents a reserved bit, E represents an extended bit, and LCID represents a logical channel identifier.

8. The evolved multimedia broadcast multicast service packet transmission method according to claim 7, wherein:

A reserved bit R in the evolved multimedia access control sub-header is enabled to indicate whether the transparent radio link control mode or the no-feedback radio link control mode is employed.

9. An evolved multimedia broadcast multicast service packet transmission method, comprising: receiving an internet protocol data packet carrying a multimedia broadcast multicast service;

Forming a transport block carrying the multimedia broadcast multicast service according to the evolved multimedia broadcast multicast service packet transmission method according to any one of claims 1 to 8 when the Internet Protocol data packet is correctly received;

The resulting transport block is transmitted to the user equipment. ·

10. The method for transmitting an evolved multimedia broadcast multicast service packet according to claim 9, further comprising:

In the case of a reception error, determining the multimedia access according to the evolved multimedia broadcast multicast service packet transmission method according to one of claims 1 to 8 according to the total number of multimedia broadcast multicast services multiplexed and the packet count. Controlling the number of fixed sections of the sub-header and the radio link control header;

According to the determined multimedia access control sub-header and wireless link control gimmick fixed The number of parts, determining the transmission duration of the transmission data to be generated by the data packet processing and the header insertion processing performed by the other base station that has not received the reception error for the Internet Protocol data packet in which the reception error occurs;

During the determined transmission duration, silence is maintained to maintain strict synchronization between the various base stations receiving the multimedia broadcast multicast service.

11. A base station comprising:

a multimedia access control sub-header insertion unit, configured to add a multimedia access control sub-header at the beginning of a last multimedia access control packet data unit that carries a multimedia broadcast multicast service in each scheduling period, and add multimedia access The number of control sub-headers is equal to the number of services in the last location of the multimedia access control packet data unit, and at the beginning of other multimedia access control packet data units, no multimedia access control sub-headers are added.

12. The base station according to claim 11, wherein:

13. The base station according to claim 11, further comprising:

a radio link control header insertion unit, configured to start at a beginning of a radio link control packet data unit in which a last segment of a radio link control service data unit carrying a multimedia broadcast multicast service is located in each scheduling period A radio link control header containing a fixed portion and an extended portion is added, and at the beginning of other radio link control packet data units, no radio link control header is added.

14. A base station, comprising:

The multimedia access control sub-header insertion unit adds an evolved multimedia access control sub-header and a multimedia access control at the beginning of the last multimedia access control packet data unit carrying a multimedia broadcast multicast service in each scheduling period. a header, and the number of multimedia access control sub-headers is equal to the number of services in the last location of the multimedia access control packet data unit, and at the beginning of other multimedia access control packet data units, adding evolved multimedia access control Subheader.

15. The base station according to claim 14, wherein:

16. The base station according to claim 14, further comprising:

a radio link control header insertion unit, configured to start at a beginning of a radio link control packet data unit in which a last segment of a radio link control service data unit carrying a multimedia broadcast multicast service is located in each scheduling period Adding a radio link control header including a fixed part and an extension part, that is, using a no-feedback radio link control mode, and at the beginning of other radio link control packet data units, without adding a radio link control header, that is, using a transparent radio chain Road control mode.

The base station according to any one of claims 14 to 16, wherein: the format of the evolved multimedia access control sub-header is R/R/E/LCID, where R represents a reserved bit and E represents an extended bit, The LCID represents the logical channel identifier.

18. The base station according to claim 17, wherein:

19. A base station, comprising:

a receiving unit, configured to receive an Internet Protocol data packet carrying a multimedia broadcast multicast service;

a transport block forming unit, configured to: when the Internet Protocol data packet is correctly received, according to the evolved multimedia broadcast multicast service packet transmission method according to any one of claims 1-8, form a bearer multimedia broadcast multicast service Transport block; and

And a transmission unit, configured to transmit the generated transport block to the user equipment.

20. The base station according to claim 19, further comprising:

a header determining unit, configured to transmit, according to one of claims 1-8, the evolved multimedia broadcast multicast service packet transmission according to the total number of multiplexed multimedia broadcast multicast services and the packet count in the case of a reception error a method, determining a number of a fixed part of a multimedia access control sub-header and a radio link control header;

a transmission duration determining unit, configured to determine, according to the determined multimedia access control sub-header and the number of fixed portions of the radio link control header, to determine other base stations that have not received a reception error for the Internet Protocol data packet in which the reception error occurs The length of transmission of the transmitted data that will be generated by the executed data packet processing and header insertion processing; And a transmission control unit, configured to control the transmission unit to remain silent during the determined transmission duration to maintain strict synchronization between the base station and other base stations receiving the multimedia broadcast multicast service.