Methods for seamless delivery of broadcast and multicast content across cell borders and/or between different transmission schemes and related apparatus

Related technology

0001Priority claim under 35 U.SC § 119 This patent application is a provisional application No. 60 / 497,457 entitled Method and MFP for Seamless Delivery of Broadcast and Multicast Content Across Cell Borders and / or Between Different Transmission Schemes filed on August 21, 2003, and August 2003. It demands priority over Provisional Application No. 60 / 497,456 entitled "L2 Design for Outer Coding Scheme" filed on the 21st, both of which are transferred to this transferee and are specifically incorporated herein by reference.

The present invention generally relates to communication systems, and in particular to the delivery of broadcast and multicast content.

Wireless communication systems have traditionally been used to carry voice traffic and low data transmission rate non-voice traffic. Today, wireless communication systems that carry high data transfer rate (HDR) multimedia traffic such as video, data, and other forms of traffic are being implemented. Multimedia Broadcasting and Multicast Services (MBMS) channels are used to transmit streaming applications based on audio, audio and video data sources such as wireless broadcasts, television broadcasts, movies, and other formats of audio or video content. To. Streaming data sources are sometimes intermittent and generally compressed, so delays and some loss or bit error can be tolerated. Therefore, the data transmission rate of incoming transmissions in a radio access network (RAN) varies greatly. Since application buffers are generally finite, an MBMS transmission mechanism that accommodates fluctuating source data rates is needed.

Base stations generally provide such multimedia traffic services to subscriber stations by transmitting information signals that are usually grouped into multiple packets. A packet is a set of bytes containing data (payload) and control elements, which are arranged in a particular format. Control elements include, for example, preambles and quality metrics, including cyclic redundancy checks (CRCs), parity bits, and other forms of metrics. Packets are usually formatted in a message according to the communication channel structure. The message travels between the source and destination terminals and is affected by the characteristics of the communication channel, such as signal-to-noise ratio, time variation, and other such characteristics. Such characteristics affect the modulated signal differently in different communication channels. Another consideration is that the transmission of the modulated information signal over the radio communication channel requires the selection of an appropriate method of protecting the information in the modulated signal. Such methods include, for example, coding, symbol repetition, and other methods known to those of skill in the art. However, these methods increase overhead. Therefore, a technical compromise must be made between the reliability of message delivery and the amount of overhead.

Operators generally have a point-to-point (PTP) connection or one point on the cell depending on the number of subscriber stations or user devices (UEs) interested in receiving MBMS content. Select one of the point-to-multipoint (PTM) connections.

Two-point (PTP) transmission uses dedicated channels to serve selected users in the reception area. The "dedicated" channel carries information from / to a single subscriber station. In two-point (PTP) transmission, separate channels are used for transmission to each mobile station. Dedicated user traffic for one-user service in the forward or downlink direction is sent, for example, through a logical channel called a Dedicated Traffic Channel (DTCH). Two-point (PTP) communication services are generally most efficient if there are not enough users requesting a particular multimedia broadcast and multicast service (MBMS) in the reception area, for example. In such cases, two-point (PTP) transmission is used in which the base station transmits the service only to the specific user who requested the service. For example, in a W-CDMA system, it is more efficient to use a dedicated channel or two-point (PTP) transmission up to a predetermined number of mobile stations.

"Broadcast communication" or "one-point to multi-point (PTM) communication" is communication on a common communication channel to a plurality of mobile stations. A "common" channel carries information to / from a large number of subscriber stations and is used simultaneously by several terminals. In a one-point-to-multipoint (PTM) communication service, for example, if the number of users requesting the service exceeds a predetermined limit within the reception area of the base station, the cell base station is multimedia traffic on a common channel. Broadcast the service. In CDMA2000 systems, PtM radio carrier (radio) Broadcasting or one-point-to-multipoint (PTM) transmissions are commonly used in place of PtP transmissions, as bearers) are almost as efficient as PtP radio carriers. Common channel transmissions from a particular base station are not always synchronized with common channel transmissions from other base stations. In a typical broadcast system, one or more central stations serve content (user's broadcast net). The central station transmits information to either all subscribers or a group of specific subscriber stations. Each subscriber station interested in broadcasting services monitors common forward line signals. One-point-to-multipoint (PTM) transmissions are sent over downlinks or common forward channels. This common broadcast forward line signal is a common traffic that generally exists in the forward line or "downline" direction. Broadcast on one-way channels such as channels (CTCH). Since this channel is one-way, allowing all subscriber units to reply to the base station would overload the communication system and the subscriber station would generally not communicate with the base station. In this way, in the one-point to multipoint (PTM) communication service, when the information received by the subscriber station is incorrect, the subscriber station cannot reply to the base station. Therefore, other means of information protection are desired.

In a CDMA2000 system, subscriber stations are loosely coupled in one-point-to-multipoint (PTM) transmission. Even when measures are taken to protect the information signal, the state of the communication channel deteriorates to the point where the destination station cannot decrypt some packets forwarded on the dedicated channel. In such cases, one strategy is to simply retransmit the undecrypted packet to the originating (base) station using an automatic retransmission reQuest (ARQ) created by the intended (subscriber) station. is there. Retransmission helps ensure the delivery of data packets. If the data cannot be delivered correctly, the RLC user on the transmission side will be notified.

Subscriber stations generally undergo transitions in some scenarios. These transitions fall into a variety of ways. For example, transitions are classified as "cross transitions" and "direct transitions". Transitions are also classified as "inter-cell" transitions and "intra-cell" transitions.

The transition between cell or transmission methods has the consequence of unfavorable service interruptions to the user. When a subscriber station or user device (UE) moves from one cell to another, or when the delivery of multimedia broadcast and multicast service (MBMS) content changes from one mode to another in the service cell. , The problem arises. Transmissions from neighboring cells are time-shifted by the amount Δt1 with respect to each other. In addition, a further delay is introduced during the transition because the mobile station needs to determine the system information in the target cell, which requires a certain amount of processing time Δt2. Data streams transmitted from different cells (or different transmission channel formats: point-to-point (PTP) / point-to-multipoint (PTM)) are offset relative to each other. Therefore, during multipoint (PTM) transmission from different cells, the mobile station may receive blocks of the same content twice, or some blocks of content may be lost, which is the Quality of Service. Service) is not preferable. The transition between cell-to-cell and / or point-to-point (PTP) transmission and one-point-to-multipoint (PTM) transmission causes interruptions in service due to the duration of the transition and delays or misalignments between transmissions.

Thus, it provides service continuity and is caused by a transition that occurs when the user device (UE) moves from one cell to another, or content delivery is between two points (PTP) in the same service cell. Transmission techniques are needed in the art to reduce the disruption in content delivery caused by the transition that occurs when changing from a connection to a one-point to multipoint (PTM) connection. Such transmission techniques would preferably allow seamless delivery across cell boundaries and / or between different transmission methods such as one-point-to-multipoint (PTM) and two-point (PTP). Let's go. A mechanism for coordinating different streams so that the data is not lost during the migration and playing content from each block of data during such migration is also desirable. It is also desirable to provide a mechanism for rearranging the data during decoding at the receiving terminal.

<figref num="1">It is a figure of a communication system.</figref><figref num="2">It is a block diagram of the UMTS signaling protocol stack.</figref><figref num="3">It is a block diagram of the packet switching user plane of the UMTS protocol stack.</figref><figref num="4">It is a block diagram of the access hierarchy part of the UMTS signal protocol stack.</figref><figref num="5A">It is a block diagram of the data transfer mode used in the Radio Link Control (RLC) layer of the UMTS signal protocol stack, and the various channels used in each layer.</figref><figref num="5B">It is a block diagram which shows the architecture of the wireless line control (RLC) layer including various RLC data transfer modes.</figref><figref num="5C">It is a block diagram which shows the entity which performs wireless line control (RLC) acknowledgment mode (AM).</figref><figref num="6">FIG. 5 is a diagram of a modified UMTS protocol stack with a forward error correction layer.</figref><figref num="7A">An embodiment of the protocol structure of the access layer including the forward error correction (FEC) layer is shown.</figref><figref num="7B">Another embodiment of the protocol structure of the access layer, including the forward error correction (FEC) layer, is shown.</figref><figref num="8">It is a figure of the information block and the external code block corresponding to the information block.</figref><figref num="9A">It is a figure which shows the external code block structure applicable to multimedia broadcasting and multicast service (MBMS) data.</figref><figref num="9B">It is a figure which shows the external code block structure of FIG. 9A in which a large number of lines are sent for each Transmission Time Interval (TTI).</figref><figref num="9C">It is the figure which shows the external code block structure of FIG.</figref><figref num="10A">It is a figure which shows the external code block generated by the forward error correction layer.</figref><figref num="10B">It is a figure which shows the external code block generated by the forward error correction layer.</figref><figref num="11">It is an embodiment of the forward error correction (FEC) layer used in the RLC UM + entity.</figref><figref num="12A">The coding process for generating an external code block from a data unit in which the row size of the external code block is fixed is shown.</figref><figref num="12B">An example of the information in FIG. 12A sent in the air is shown.</figref><figref num="13">The coding process for generating the external code block having various row sizes is shown.</figref><figref num="14">FIG. 5 is a diagram of an embodiment of a forward error correction (FEC) header format.</figref><figref num="15">An algorithm that allows a mobile station to delay decoding due to a time offset between different logical streams.</figref><figref num="16">External code blocks received by a mobile station when the mobile station transitions while receiving one-point-to-multipoint (PTM) transmission from cell A and another one-point to multipoint (PTM) transmission from cell B. It is a figure which shows the time relationship between.</figref><figref num="17">FIG. 5 shows the time relationship between external code blocks received by a mobile station when a transition occurs between one-point-to-multipoint (PTM) transmission and two-point (PTP) transmission.</figref><figref num="18">Move during transition or relocation between two-point (PTP) transmission from wireless network controller (RNC) A and another two-point (PTP) transmission from wireless network controller (RNC) B It is a figure which shows the time relationship between the external code blocks received by a station.</figref>

The term "exemplary" here means "useful as an example, case, or example." The embodiment shown herein as "typical" is not always construed as favorable or advantageous over other embodiments.

The term "mobile station" is used here as the term "destination station", "subscriber station", "subscriber unit", "terminal" and "User". Compatible with "Equipment: UE)", it is used here to refer to hardware such as base stations with which an access network such as UMTS terrestrial wireless connection network (UTRAN) communicates. In a UMTS system, a user device (UE) is a device that allows a user to access UMTS network services and, more preferably, contains a USIM that contains all user reservation information. Mobile stations are mobile or stationary and generally include, for example, communication devices, data devices or terminals that communicate over wireless or wired channels using fiber optics or coaxial cables. Mobile stations are embodied in devices including, but not limited to, PC cards, CompactFlash, external or internal modems, or wireless or wired telephones.

The term "connection setup state" refers to the state in which a mobile station is in the process of establishing an operational traffic channel connection with a base station.

The term "traffic state" refers to the state in which a mobile station has established an operational traffic channel connection with a base station.

The term "communication channel" is used here to mean a physical channel or a logical channel depending on the context.

The term "physical channel" is used herein to refer to a channel that carries user data or control information on an aerial interface. Physical channels are "transmission media" that provide a wireless platform on which information is actually transferred and help carry communications and user data over wireless lines. Physical channels generally include a combination of frequency scrambled and channelized codes. In the uplink direction, relative phase is also included. Several different physical channels are used in the uplink direction based on what the mobile station is trying to do. In UMTS systems, the term "physical channel" refers to different types of bandwidth allocated for different purposes on the Uu interface. The physical channel forms the physical presence of the Uu interface between the user equipment (UE) area and the network connection area. Physical channels are defined by the physical maps and attributes used to transfer data over the aerial interface.

The term "transport channel" is used herein to refer to a communication route for transporting data between peer physical layer entities. Transport channels relate to the way information is transmitted. There are two types of transport channels, commonly known as Common Transport Channels and Dedicated Transport Channels. Transport channels are defined by, for example, using either dedicated or common physical channels, or multiplexing of logical channels, and how and what characteristic data is transferred to the physical layer over the aerial interface. Will be done. The transport channel acts as a service access point (SAP) for the physical layer. In UMTS systems, transport channels describe how logical channels are transferred and the flow of this information is mapped to physical channels. The transport channel is Medium Access Used to carry signals and user data between the Control: MAC) layer and the physical layer (LI). The Radio Network Controller (RNC) looks at the carrier channel. Information is passed from the MAC layer to the physical layer on any one of several transport channels mapped to the physical channel.

The term "logical channel" is used herein to refer to an information stream or wireless interface dedicated to the transfer of certain forms of information. Logical channels relate to the information being transmitted. Logical channels are defined by what form of information is transferred, such as communication or user data, and are understood as different tasks that networks and terminals must perform at different times. The logical channel is mapped to a carrier channel that actually transfers information between the mobile station area and the access area. Information is passed via a logical channel that is mapped via a transport channel that is mapped to a physical channel.

The term "dedicated channel" is generally used here to refer to a channel that is dedicated or provided to a particular user and that carries information from or to a particular mobile station, subscriber unit, or user equipment. Used for. Dedicated channels typically carry information for a user and contain data for the actual service as well as higher layer control information. Dedicated channels are identified by a code at a frequency. Dedicated channels are potentially bidirectional to allow feedback.

The term "common channel" is used herein to refer to a carrier channel that carries information from / to a large number of mobile stations. On a common channel, information is shared among all mobile stations. Common channels are distributed among all users or users in a group of cells.

The term "point-to-point (PTP) communication" is used here to mean communication transmitted to a single mobile station on a dedicated physical communication channel.

The term "broadcast communication" or "Point-to-Multipoint (PTM) communication" is used here to refer to communication to multiple mobile stations on a common communication channel. ..

The term "reverse link" or "uplink channel" is used herein to refer to a communication channel / line in which a mobile station sends a signal to a base station in a wirelessly connected network. This channel is also used to transmit signals from mobile station to mobile station or from mobile station to base station.

The term "forward link or downlink channel" is used herein to mean a communication channel / line through which a wirelessly connected network sends a signal to a mobile station.

The term "Transmission Timing Interval (TTI)" is used here to refer to how often data arrives from the higher layers to the physical layer. The transmission time interval (TTI) is the arrival time interval of the Transport Block Set (TBS), which is approximately equal to the period at which TBS is transferred by the physical layer on the wireless interface. The data sent over the transport channel during the TTI is encoded and interleaved together. TTI is a multiple of the minimum interleaving period over a large number of radio frames. The TTI start positions for different transport channels that are multiplexed together for a single connection are time aligned. TTIs have a common starting point. Media access control delivers a set of transport blocks to the physical layer for each TTI. Different transport channels mapped on the same physical channel have different transmission time interval (TTI) durations. Many PDUs are sent in one TTI.

The term "packet" is used herein to mean a group of bits and includes data or payloads and control elements arranged in a particular format. Control elements include, for example, preambles, quality metrics, and others known to those of skill in the art. Quality metrics include, for example, Cyclic Redundancy Checks (CRCs), parity bits and others known to those of skill in the art.

The term "access network" is used herein to mean the equipment needed to access a network. A connected network includes a collection of base stations (BS) and a network and one or more base station controllers (BSCs). The connected network carries data packets between a large number of subscriber stations. The connected network is further connected to additional networks outside the connected network, such as the corporate intranet or the Internet, and carries data packets between the access terminal and such an outer network. In UMTS systems, the connection network is called the UMTS Terrestrial Radio Access Network (UTRAN).

The term "core network" is used for public switched telephone networks (PSTN) for circuit-switched calls in the circuit-switched (CS) area and packets for packet-switched calls in the packet-switched (PS) area. Used here to refer to switching and routing capabilities for connecting to any of the data networks (PSDN). The term "core network" also refers to mobility and subscriber location management, and the ability to allocate routes for authentication services. The core network contains the network elements necessary for exchange and subscriber control.

The term "base station" is used herein to refer to an "origination station" that includes the hardware with which the mobile station communicates. In UMTS systems, the term "node B" is used interchangeably with the term "base station". Base stations are fixed or mobile.

The term "cell" is used herein to refer to either hardware or geographical coverage, depending on the context in which the term is used.

The term "Service Data Unit (SDU)" is used herein to refer to a data unit that is exchanged for a protocol above the protocol of interest.

The term "Payload Data Unit (PDU)" is used here to refer to a data unit that is exchanged for a protocol below the protocol of interest, even if the protocol of interest is ambiguous. For example, the name will have a specific description, for example, the FEC-PDU is a FEC layer PDU.

The term "soft handoff" is used here to mean communication between a subscriber station and two or more sectors, where each sector belongs to a different cell. Reverse line communication is received by both sectors, and forward line communication is carried simultaneously on the forward lines of two or more sectors.

The term "softer handoff" is used here to mean communication between a subscriber station and two or more sectors, where each sector belongs to the same cell. Reverse line communication is received by both sectors, and forward line communication is carried simultaneously by one of the forward lines of two or more sectors.

The term "erasure" is used here to mean the unsuccessful recognition of a message, and to refer to a set of bits that are missed during decryption.

The term "cross transition" is defined as the transition from two-point (PTP) transmission to one-point-to-multi-point (PTM) transmission, and so on. The reverse is also true. From two-point (PTP) transmission in cell A to one-point to multipoint (PTM) transmission in cell B, from one-point to multipoint (PTM) transmission in cell A to two-point (PTP) transmission in cell B. From two-point (PTP) transmission in cell A to one-point to multipoint (PTM) transmission in cell A, and from one-point to multipoint (PTM) transmission in cell A to two-point (PTP) transmission in cell A There are four possible crossover transitions.

The term "direct transition" is defined as the transition from one two-point transmission to another two-point transmission and from one-point-to-multipoint transmission to one-point-to-multipoint transmission. From two-point (PTP) transmission in cell A to two-point (PTP) transmission in cell B, and from one-point to multipoint (PTM) transmission in cell A to one-point to multipoint (PTM) transmission in cell B There are two possible direct transitions.

The term "inter-cell transition" is used to refer to a transition that crosses cell boundaries. From two-point (PTP) transmission in cell A to two-point (PTP) transmission in cell B, from one-point to multipoint (PTM) transmission in cell A to one-point to multipoint (PTM) transmission in cell B. From two-point (PTP) transmission in cell A to one-point to multipoint (PTM) transmission in cell B, and from one-point to multipoint (PTM) transmission in cell A to two-point (PTP) transmission in cell B There are four possible cell-to-cell transitions. In general, the most frequent transition is one-point-to-multipoint (PTM) transmission to one-point-to-multipoint (PTM) transmission across cell boundaries.

The term "intra-cell transition" is used to refer to an intra-cell transition from one mode to another. From two-point (PTP) transmission in cell A to one-point to multipoint (PTM) transmission in cell A, and from one-point to multipoint (PTM) transmission in cell A to two-point (PTP) transmission in cell A There are two possible intra-cell migrations.

The term "radio bearer" is used to refer to the services provided by Layer 2 for the transfer of user data between the User Equipment (UE) and the UMTS Terrestrial Radio Connection Network (UTRAN). To.

Examples of the present invention in which the above embodiments are implemented in a W-CDMA or UMTS communication system will be discussed below. Figures 1-5C illustrate some forms of conventional UMTS or W-CDMA systems in which the forms of the invention described herein are presented for purposes of illustration and limitation. The embodiments of the present invention can also be applied to other systems that carry both voice and data, such as GSM® systems and CDMA2000 systems that comply with the "3rd Generation Partnership Project (3GPP)". Yes, document numbers 3G TS25.211, 3G TS25.212, 3G TS25.213, and 3G TS25.214 (W-CDMA standard), or "TR-45.5 cdma2000 spread spectrum system" (IS2000 standard), and TS04.08 What can be embodied in a set of documents including GSM specifications such as (mobile wireless interface layer 3 specifications), TS05.08 (wireless subsystem line control), and TS05.01 (physical layer on wireless path (general description)) Should be recognized.

For example, the wireless connection network 20 is a GSM, although the description states that the wireless connection network 20 will instead be implemented using the All Ground Radio Connection Network (UTRAN) aerial interface in the GSM / GPRS system. / EDGE Radio Connection Network (GERAN), in the case of a interconnect, it contains cells for UTRAN aerial interfaces and cells for GSM / EDGE aerial interfaces.

<u style="single">UMTS network topology</u> Figure 1 is a block diagram of a communication system based on the UMTS network topology. The UMTS system includes 10 user devices (UEs), 20 connected networks, and 30 core networks. UE10 is connected to the connection network connected to the core network 30 which is connected to the external network.

UE10 includes a mobile device 12 containing user reservation information and a Universal Subscriber Identity Module (USIM) 14. The Cu interface (not shown) is the electrical interface between the USIM 14 and the mobile device 12. UE10 is generally a device that allows users to access USIM network services. UE10 is a mobile such as a mobile phone, fixed station, or other data terminal. A mobile device is, for example, a wireless terminal used for wireless communication over an aerial interface (Uu). The Uu interface is the interface by which the UE accesses a fixed part of the system. USIM is an application that resides on a "smart card" or other logical card, generally including a microprocessor. The smart card holds the subscriber certificate, executes the authentication algorithm, and stores the authentication in the encryption key and subscription information required by the terminal.

The connection network 20 includes a wireless device for accessing the network. In a W-CDMA system, the connection network 20 is a Universal Terrestrial Radio Access Network (UTRAN) aerial interface. UTRAN includes at least one base station connected to at least one radio network controller (RNC) 24 or at least one radio network subsystem (RNS) including "node B" 22.

RNC controls UTRAN's radio resources. The RNC24 of the connection network 20 communicates with the core network 30 via the Iu interface. The Uu interface, Iu interface 25, Iub interface, and Iur interface allow interconnect operation between devices from different suppliers and are specified in the 3GPP standard. Implementations of wireless network controllers (RNCs) vary from supplier to supplier and will therefore be presented as a general theory below.

The wireless network controller (RNC) 24 serves as a switch and control element for the UMTS Terrestrial Radio Connection Network (UTRAN) and is located between the Iub interface and the Iu interface 25. RNC acts as a service access point for managing all services that UTRAN provides to its core network 30, such as connections to user equipment. Iub interface 23 connects to node B22 and wireless network controller (RNC) 24. The Iu interface connects UTRAN to the core network. Wireless network controller (RNC) is an Iu carrier (Iu) Provides a switching point between bearer) and the base station. The user device (UE) 10 has several wireless carriers between itself and the wireless network controller (RNC). The radio carrier is related to the user equipment (UE) context, which is a set of definitions required by Iub to provide common and dedicated connections between the user equipment (UE) and the wireless network controller (RNC). There is. Each RNC24 communicates with each other on any Iur interface that allows soft handover between cells connected to different nodes 22. The Iur interface thus allows RNC-to-RNC connections. In such cases, the service RNC maintains the Iu connection 25 to the core network 30 and performs selector and external loop power control functions, while the idle RNC maintains the mobile station 10 via one or more base stations 22. Transfer exchangeable frames on the Iur interface to.

The RNC that controls one node B is called the node B control RNC, which controls the load and congestion of its own cells, and also the approval control for new radio lines to be established in those cells. Perform code assignment.

The RNC and base station (or node B) are connected via Iub interface 23 and communicate on it. The RNC controls the use of radio resources by each base station 22 connected to a particular RNC 24. Each base station 22 controls one or more cells and provides a wireless line to the mobile station 10. The base station performs interface processing such as channel coding and interleaving, transmission rate adaptation and spreading. Base stations also perform basic radio resource management operations such as inter-loop power control. Base station 22 transforms the data flow between Iub and Uu interfaces 23, 26. Base station 22 is also involved in radio resource management. The aerial interface Uu26 connects each base station 22 to the mobile station 10. The base station is involved in radio transmission in one or more cells to mobile station 10 and radio reception in one or more cells from mobile station 10.

The core network 30 should be connected to either (1) PSDN42 if there is a circuit-switched call, or packet-data network (PDN) if there is a packet-switched call, (2) mobility and subscriber location management, and (3). ) Includes all switching and routing capabilities for authentication services. Core Network 30 includes Positional Register (HLR) 32, Mobile Exchange Service Center / Visitor Location Register (MSC / VLR) 34, Gateway Mobile Exchange Center (GMSC) 36, General Service Packet Radio Service Support Node (SGSN) 38, Includes Gateway GPRS Support Node (GGSN) 40.

The core network 30 is connected to an external circuit switching (CS) network 42 that provides a circuit switching connection such as a public switched telephone network (PTSN) or ISDN if there is a packet switching call, or a packet if there is a packet switching call. Connected to a PS network 44, such as the Internet, which provides data service connectivity.

<u style="single">UMTS signal protocol stack</u> FIG. 2 is a block diagram of the UMTS signal protocol stack 110. The UMTS signal protocol stack 110 includes an access hierarchy and a non-access hierarchy (NAS).

The access layer generally includes a physical layer 120, a layer 2 (130) including a media access control (MAC) layer 140 and a radio line control (RLC) layer 150, and a radio resource control (RRC) layer 160. The various layers of the access hierarchy are described in more detail below.

The UMTS non-access layer is essentially the same as the GSM upper layer and is divided into a circuit switching part 170 and a packet switching part 180. The circuit exchange part 170 includes a connection management (CM) layer 172 and a mobility management (MM) layer 178. CM layer 172 handles circuit exchange calls and includes various sublayers. The call control (CC) lower layer 174 performs functions such as establish and release. Auxiliary service (SS) lower layer 176 performs functions such as call transfer and three-way calling. Short Message Service (SMS) Sublayer 177 runs a short message service. MM layer 178 handles location update and circuit exchange call authentication. The packet switching part 180 includes a session management (SM) lower layer 182 and a GPRS mobility management (GMM) lower layer 184. The session management (SM) lower layer 182 handles packet-switched calls by performing functions such as build and release, and also includes a short message service (SMS) unit 183. GMM lower layer 184 handles location update and packet switching call authentication.

Figure 3 is a block diagram of the packet-switched user plane of the UMTS protocol stack. The stack includes an access hierarchy (AS) layer and a non-access hierarchy (NAS) layer. The NAS layer includes an application layer 80 and a packet data protocol (PDP) layer 90. Application layer 80 is provided between user equipment (UE) 10 and remote user 42. PDP layer 90, such as IP or PPP, is provided between the GGSN 40 and User Equipment (UE) 10. The Low Layer Packet Protocol (LLPP) 39 is provided between the remote user 42 and the SGSN 38. The Iu interface protocol 25 is provided between the wireless network controller (RNC) 24 and SGSN38, and the Iub interface protocol is provided between the wireless network controller (RNC) 24 and node B22. Other parts of the AS layer are shown below.

<u style="single">Access Hierarchy (AS) Layer</u> Figure 4 is a block diagram of the access hierarchy of the UMTS signal protocol stack. Traditional access layers are Physical Layer (L1) 120, Media Access Control (MAC) Layer 140, Wireless Line Control (RLC) Layer 150, Packet Data Convergence Protocol (PDCP) Layer 156, Broadcast / Multicast Control (BMC) Layer It includes a data line layer (L2) 130 having a lower layer including 158, and a radio resource control (RRC) layer 160. These layers are further described below.

The wireless carrier carries user data 163 between the application layer and layer 2 (L2) 130. The control plane signal 161 is used for all UMTS specific control signals and includes the application protocol as a signal carrier for carrying the application protocol message. The application protocol is used to configure the carrier in UE10. The user plane carries all user plane information 163 sent and received by the user, such as a coded voice in a voice call or a packet in an internet connection. User plane information 163 carries data streams and data carriers for these data streams. Each data stream is characterized by one or more frame protocols specified for its interface.

The radio resource control (RRC) layer 160 functions as an overall control of the access hierarchy and constitutes all other layers in the access hierarchy. RRC layer 160 includes wireless line control unit 152, physical layer (L1) 120, media access control (MAC) layer 140, wireless line control (RLC) layer 150, packet data convergence protocol (PDCP) layer 156, and broadcast / Generates a control plane signal 161 that controls multicast control (BMC) layer 158. Radio Resource Control (RRC) Layer 160 determines the form of measurement to be made and reports those measurements. The RRC layer 160 also serves as a control and signal interface for the non-access layer.

In particular, the RRC layer 160 broadcasts system information messages, including both access and non-access layers, to all user devices (UEs) 10. RRC layer 160 establishes, maintains, and disconnects a radio resource control (RRC) connection between UTRAN 20 and UE 10. UE RRC requests a connection, while UTRAN RRC sets up and disconnects a connection. The RRC layer 160 also establishes, reconstructs, and disengages the radio carrier between the UTRAN 20 and the UE 10 by the UTRAN 20 that initiates these operations.

RRC layer 160 also handles various forms of mobility of user equipment (UE) 10. These procedures depend on the UE state, that is, whether the call is a circuit exchange call or a package exchange call, and the new cell wireless connection technology (RAT). RRC layer 160 also paginates UE10. UTRAN RRC pages the UE regardless of whether the UE is listening to the paging channel or the paging indicator channel. UE's RRC notifies the upper layers of Core Network (CN) 30.

Data line layer (L2) 130 is media access control (MAC) lower layer 40, wireless line control (RLC) lower layer 150, packet data convergence protocol (PDCP) lower layer 156, and broadcast / multicast control (BMC) lower layer. Includes layer 158.

The Broadcast and Multicast Control Protocol (BMC) 158 carries messages originating from the cell broadcasting center on the wireless interface by adapting the broadcasting / multicast service originating from the broadcasting area on the wireless interface. BMC Protocol 158 is "a radio It provides a service called "bearer)" and exists on the user plane. BMC Protocol 158 and RNC store cell broadcast messages received on CBC-RNC for scheduled transmission. On the UTRAN side, the BMC158 calculates the transmission rate required for the cell broadcast service based on the message received on the CBC-RNC interface (not shown) and requests the appropriate CTCH / FACH resources from the RRC. .. The BMC protocol 158 also receives scheduling information along with each cell broadcast message on the CBC-RNC interface. Based on this scheduling information, the BMC on the UTRAN side generates a scheduled message, and thus a scheduled BMC message. On the user equipment side, the BMC estimates the scheduling message and presents the scheduling parameters to the RRC used by the RRC to form the lower layer for discontinuous reception. The BMC also transmits the schedule and cell broadcast messages according to the schedule. The undamaged cell broadcast message is delivered to the upper layer. Part of the control signal between UE10 and UTRAN20 is Radio Resource Control (RRC), which carries all the parameters needed to configure, modify, and deactivate Layer 2 Protocol 130 and Layer 1 Protocol 120 entities. 160 messages. RRC messages carry all high layer signals in their payload. Radio resource control (RRC) controls the mobility of the user device in connection mode by signals such as measurement, takeover and cell update.

Packet Data Convergence Protocol (PDCP) 156 resides in the user plane for services from the PS domain. The services provided by PDCP are called wireless carriers. The Packet Data Convergence Protocol (PDCP) provides a header compression service. Packet Data Convergence Protocol (PDCP) 156 includes a compression method that provides better spectral efficiency for services that transmit IP packets wirelessly. Any of the several header compression algorithms can be used. PDCP compresses redundant protocol information in the transmitting entity and decompresses it in the receiving entity. Header compression methods are specific to a particular network layer, carrier layer, or upper layer protocol combination, such as TCP / IP and RTP / UDP / IP. PDCP also transfers the user data it receives from the non-access layer in the form of a PDCP service data unit (SDU) and sends them to the RLC entity. The reverse is also true. PDCP also provides support for lossless SRNS relocation. PDCP Acknowledged Mode: AM) When using RLC in sequence delivery, the PDCP entity configured to assist in loss RSRNS relocation has a protocol data unit (PDU) sequence number, which is relocated with unidentified PDCP packets. In the meantime, it will be sent to the new SRNC.

The RLC layer 150 is used by the higher layer protocol on the UE side and serves the higher layer (eg, non-access layer) via the service access point (SAP) used by the IURNAP protocol on the UTRAN side. The Service Access Point (SAP) describes how the RLC layer handles data packets. All high-level signals such as mobility management, call control, session management, etc. are encapsulated in RLC messages related to the transmission of wireless interfaces. The RLC layer 150 includes various wireless line control entities 152 connected to the MAC layer 140 via logical channels that carry signal information and user data.

On control plane 161 the RLC service is used by the RLC layer for signal delivery. On the user plane 163, the RLC service is used by either the service specific protocol layer PDCP or BMC, or any other higher layer user plane feature. The RLC service is referred to as a signal radio carrier in control plane 161 and a radio carrier in user plane 163 for services that do not utilize PDCP156 and the user plane protocol. In other words, the RLC layer 150 provides a service called signal radio carrier (SRB) on control plane 161 and a service called radio carrier (RB) on user plane 163 if PDCP and BMC are not used by that service. .. In other cases, RB services are provided by PDCP layer 156 or BMC layer 158.

The wireless line control (RLC) layer 150 performs a framing function on the user and control data, which includes segmentation / concatenation and padding functions. The RLC layer 150 generally provides a division and concatenation service to the radio resource control (RRC) layer for control data in control plane 161 and to the application layer for user data in user plane 163. The RLC layer typically performs segmentation / reconstruction of variable length higher layer protocol data units (PDUs) from / to smaller RLC protocol data units (PDUs). One Radio Line Control (RLC) Protocol Data Unit (PDU) generally has one PDU. The size of the wireless line control (RLC) PDU is set according to the minimum possible bit ratio of the service, for example, using wireless line control (RLC). As discussed below, for variable bit rate services, some radio line control (RLC) PDUs are transmitted during one transmission time interval (TTI) when any bit rate is higher than the lowest one used. Will be done. The RLC transmission entity also performs the concatenation. If the contents of the Radio Line Control (RLC) Service Data Unit (SDU) do not satisfy an integer number of Radio Line Control (RLC) PDUs, the first segment of the next Radio Line Control (RLC) SDU is the previous RLC SDU. Concatenated with the last segment of the radio line control (RLC) PDU. The RLC transmission entity also performs the jamming function. If the remaining data to be transmitted does not meet a certain size of the entire wireless line control (RLC) PDU, the rest of the data field is filled with packing bits. Techniques are provided for reducing or removing, for example, the amount of clogging utilized, according to the embodiments of the invention discussed below with reference to FIGS. 11-13.

The RLC receiving entity detects duplicate received wireless line control (RLC) PDUs and ensures that the results in the higher layer PDUs are delivered to the higher layers. The RLC layer also controls the rate at which the PRLC transmitting entity sends information to the RLC receiving entity.

Figure 5A illustrates the data transfer modes used in the wireless line control (RLC) layer of the UMTS signal protocol stack and is a block diagram showing possible mappings of logical, transport and physical UMTS channels with respect to the access hierarchy. Those skilled in the art will appreciate that not all maps are necessarily defined for a user device (UE) at the same time, and that multiple instantiations of several maps occur at the same time. For example, a voice call would use three dedicated traffic channel (DTCH) logical channels mapped to three dedicated channel (DCH) transport channels. In addition, some channels shown in Figure 5, such as CPICH, SCH, DPCCH, AICH and PICH, exist in the physical layer context and do not carry upper user layer signals and user data. The content of these channels is defined at physical layer 120 (L1).

Each RLC instance in the radio line control (RLC) layer is in one of three modes: by the radio resource control (RRC) layer operating in transparent mode (TM), negative response mode (UM), or acknowledgment mode (AM). It is configured and it is described in detail below with reference to FIG. 5B. The three data transfer modes indicate the modes in which wireless line control (RLC) is configured for the logical channel. Transparent and negative response mode RLC entities are defined as unidirectional, while acknowledgment mode entities are bidirectional. Normally, for all RLC modes, CRC error detection is performed on the physical layer, and the results of the CRC inspection are delivered to RLC along with the actual data. Depending on the specific requirements of each mode, these modes perform some or all of the functions of the RLC150, which are segmentation, reconfiguration, concatenation, jamming, retransmission control, flow control, duplication detection, discontinuity. Includes delivery, error correction and encryption. These functions are described in more detail below with reference to FIGS. 5B and 5C. A new wireless line control (RLC) data transfer mode is provided according to the embodiments of the invention discussed herein.

The MAC layer 140 serves the RLC layer 150 by a logical channel whose characteristics are determined by the format of the transmitted data. The media access control (MAC) layer 140 maps and multiplexes the logical channel to the transport channel. MAC layer 140 identifies a user device (UE) on a common channel. MAC layer 140 also multiplexes / demultiplexes higher layer PDUs from / to transport blocks that deliver higher layer PDUs to / from common transport channels. MAC deals with services that multiplex for common transport channels because it is not done at the physical layer. The media access control (MAC) header contains the identity of the UE when the common transport channel transports data from the dedicated logical channel. The MAC layer also multiplexes / demultiplexes higher layer PDUs from / to the transport block set delivered to or from the physical layer on a dedicated channel.

MAC layer 140 receives an RLC PDU with state information about the amount of data in the RLC transmission buffer. MAC layer 140 compares the amount of data corresponding to the transport channel with the threshold set by RRC layer 160. If the amount of data is too high or too low, the MAC will send a measurement report on the traffic state to the RRC. RRC layer 160 also requires MAC layer 140 to transmit these measurements on a regular basis. RRC layer 160 uses these reports to initiate the reconfiguration of radio carriers and / or transport channels.

The MAC layer selects the appropriate transport format (TF) for each transport channel according to the instantaneous source rates of the logical channels. MAC layer 140 gives priority to data streams by selecting "high bit rate" and "low bit rate" transport formats (TF) for different data streams. Packet-switched (PS) data is spontaneous in nature, so the amount of available data to send varies from frame to frame. When more data is available, MAC layer 140 chooses one of the higher data rates, however, when both signal and user data are available, MAC layer 140 has a higher priority channel. Choose between them to maximize the amount of data sent from. The transport format (TF) is selected for each connection with respect to the transport format combination (TFC) defined by the approval control.

The media access control (MAC) layer also performs encryption. Each wireless carrier is encrypted separately. Details of the encryption are given in 3GPP TS 33.102.

In systems such as W-CDMA, there are three types of transport channels used to send packet data. These channels are known as common transport channels, dedicated transport channels, and shared transport channels. On the downlink, the carrier channel packet data is selected by the packet scheduling algorithm. On the uplink, the carrier channel is selected by mobile station 10 based on the parameters set by the packet scheduling algorithm.

The common channel is, for example, the random access channel RACH on the uplink and the forward access channel FACH on the downlink. Both carry signal data and user data. Common channels have a low set time. Since the common channel is used for communication before the connection is set up, the common channel is used to send packets immediately rather than a long set time. Generally there are several RACHs or FACHs per sector. Common channels do not have feedback channels and therefore generally use open-loop power control and fixed power. In addition, common channels cannot use soft handovers. As described above, the line level performance of the common channel is worse than that of the dedicated channel, and more interference occurs than that of the dedicated channel. Therefore, common channels are more suitable for sending small individual packets. Applications used on the common channel will be applications such as short message services, and short text email. Sending a single request to a web page also fits well with the concept of a common channel, however, with larger amounts of data, the common channel suffers from poor radio performance.

Dedicated channels can use soft handover characteristics that improve high-speed power control and radio performance, and generally produce less interference than common channels. However, setting up a dedicated channel takes more time than accessing a common channel. Dedicated channels have variable bit rates from a few kilobytes per second to 2 megabytes per second. Since the bit ratio changes during transmission, the downlink orthogonal code must be assigned according to the highest bit ratio. Therefore, a dedicated channel with a variable bit rate consumes an expensive downlink orthogonal code space.

The physical layer (L1) 120 couples to the MAC layer 140 via a carrier channel that carries signal information and user data. The physical layer 120 provides services to the MAC layer via a transport channel whose characteristics are determined by how and with what characteristics data is transferred.

The physical layer (L1) 120 receives signals and user data on the wireless line via the physical channel. The physical layer (L1) generally includes other physical layer procedures such as acquisition, access, pagination, and wireless line establishment / failure, as well as multiplexing and channel coding, including CRC calculations, forward error correction (FEC), Performs transmission rate adjustment, transport channel data interleaving, and transport channel data multiplexing. The physical layer (L1) is also responsible for spreading and scrambling, modulation, measurement, transmission diversity, power weighting, handover, compression mode and power control.

Figure 5B is a block diagram showing the architecture of the wireless line control (RLC) layer. As mentioned above, each RLC entity or instance 152 in the radio line control (RLC) layer 150 is one of three data movement modes depending on the radio resource control (RRC) layer: transparent mode (TM), negative response mode. It consists of a radio resource control (RRC) layer that operates in (UM), or acknowledgment mode (AM). The data transfer mode for user data is controlled by quality of service (QoS) settings.

TM is one-way and includes transmit TM entity 152A and receive TM entity 152B. In transparent mode, protocol order is not added to higher layer data. The erroneous protocol data unit (PDU) is either discarded or marked as erroneous. In special cases, streaming transmission is generally used in which high-level data is not segmented, although limited segmentation / reconstruction is achieved. When segmentation / reconstruction is used, it is negotiated in the radio carrier setup procedure.

The UM is also one-way and includes the sending UM entity 152C and the receiving UM entity 152D. A UM RLC entity is defined as one-way because no association between the uplink and downlink is required. Data delivery is not guaranteed by UM. For example, UM is used for certain RRC signaling procedures where acknowledgment and retransmission are not part of the RRC procedure. Examples of user services that use negative response mode RLC are cell broadcasting services and voice over IP. Received error data is marked or discarded depending on the configuration. Timer-based discard without explicit signal function applies and thus RLC not sent within the specified time PDUs are simply removed from the transmit buffer. In negative response data transfer mode, the PDU structure includes the sequence number and the sequence number check is performed. Series number checking helps ensure the integrity of reconstructed PDUs, and when they are rebuilt into a radio line control (RLC) SDU, the broken radio by checking the series number in the radio line control (RLC) PDU. Provides a means of detecting line control (RLC) SDU. Any corrupted radio line control (RLC) SDU is discarded. Segmentation and concatenation is also done in negative response mode (UM).

In acknowledgment mode, the RLC AM entity is bidirectional and can conjugate line condition indications in the opposite direction into user data. FIG. 5C is a block diagram showing an entity that implements a wireless line control (RLC) acknowledgment mode (AM) entity and how an AM PDU is constructed. Data packets (RLC SDUs) received from higher layers via AM-SAP are segmented and / or concatenated into fixed-length protocol data units (PDUs) (514). The length of the protocol data unit is a semi-static value determined on the configured radio carrier and can be changed by the RRC radio carrier reconstruction procedure. For concatenation or packing purposes, a bit with length and extension information is inserted at the beginning of the last protocol data unit, or data from the SDU is included. If several SDUs fit into one PDU, they are linked to the appropriate length index (LI) and inserted at the beginning of the PDU. The PDU is then placed in transmission buffer 520, which is also responsible for retransmission management.

A PDU is constructed by taking one PDU from transmit buffer 520 and adding a header for it, and if the data in the PDU does not fill all RLC PDUs, a padding field or conjugation state message is added. Will be done. The conjugation status message originates from the receiving side or the transmitting side to instruct the RLC SDU to be discarded. The header is the RLC PDU sequence number (SN), pole bit (P) (which is used to request the status from the peer entity), and the concatenation of the SDU, jamming, or conjugation PDU is lined in the RLC PDU. Includes any length index (LI) used, if any.

Acknowledgment mode (AM) is commonly used for packet-based services such as Internet browsing and email downloads. In acknowledgment mode, the automatic repeat request (ARQ) mechanism is used for error correction. Any received packet with an error will be retransmitted. The quality vs. delay performance of RLC is controlled by RLC through several retransmission configurations provided by RLC. If the RLC does not deliver the data correctly, for example, if the maximum number of retransmissions arrives or the transmission time is exceeded, the upper layer will not be notified and the wireless line control (RLC) SDU will be discarded. .. The peer entity is also notified of the SDU discard operation by sending a mobile receive window command during the status message, so that the receiver removes all PDUs belonging to the discarded Radio Line Control (RLC) SDU.

RLC consists of both in-sequence and out-of-sequence deliveries. In-line delivery maintains the order of the higher layers of PDUs, while out-of-line delivery forwards higher layer PDUs as soon as they are fully received. The RLC layer provides intra-series delivery of higher layer PDUs. This feature maintains the order of the higher layer PDUs presented for transfer by RLC. If this feature is not used, out-of-line delivery will occur. In addition to data PDU delivery, state and reset control procedures are communicated between peer RLC entities. The control procedure, of course, uses separate logical channels, thus one AM RLC entity uses either one or two logical channels.

Encryption is performed at the RLC layer for acknowledgment and negative response RLC modes. In Figure 5C, the AM RLC PDU is encrypted excluding the first two bits, including the PDU sequence number and the pole bit (540). The PDU sequence number is an input parameter to the encryption algorithm and must be readable by the peer entity for encryption. The 3GPP specification TS33.102 states encryption.

The PDU is then sent to the MAC layer 140 via the logical channel. In Figure 5C, a special logical channel (DCCH / DTCH) is indicated by a dashed line, exemplifying that one RLC entity is configured to send control and data PDUs using different logical channels. The receiving side 530 of the AM entity receives the RLC AM PDU from the MAC layer through one of the logical channels. Errors are checked by the physical layer CRC, which is calculated on all RLC PDUs. The actual CRC check is done at the physical layer, the RLC entity receives the result of the CRC check along with the data after decoding all the headers, and possible conjugation state information is extracted from the RLC PDU. If the PDU received was a strong message, or the status information is AM When combined with the PDU, the control information (status message) is passed to the sender that inspects the retransmission buffer for the received status information. The PDU number from the RLC header is used for decryption (550) and when storing the encrypted PDU in the receive buffer. Once all PDUs belonging to the complete SDU are in the receive buffer, the SDU is rebuilt. Although not shown, intra-series delivery and duplicate detection occur before the RLC SDU is delivered to the higher layers.

The RLC entity 152 is reinitialized when the user equipment (UE) or mobile station moves (or changes cells) between PTM and two-point (PTP) transmissions. This has the undesired consequence of losing any data in the wireless line control (RLC) buffer. As mentioned above, when a mobile station moves from one cell to another, or when multimedia broadcast and multicast service (MBMS) content is transmitted in a service cell from two-point (PTP) transmission to one-point-to-many. Problems arise when switching to point (PTM) transmission.

Multimedia broadcasting and multicast services between transitions between two-point (PTP) transmissions and one-point-to-multipoint (PTM) transmissions, or between transitions that occur between different cells (eg, handovers). It is desirable to maintain (MBMS) and avoid the presentation of duplicate information. In order to maintain the continuity of the MBMS service and avoid the presentation of duplicate information, Layer 2 (150) must be able to reorganize the data coming from the two streams. This synchronization cannot be done by the physical layer because the network terminal points are different in each mode. As in 3GPP2, if forward error correction (FEC) is performed below RLC layer 150, the data will be between one-point-to-multipoint (PTM) and two-point (PTP) transmissions during any transition. Lost to. The reverse is also true. In addition, this will require physical layer synchronization and sharing of the same media access control (MAC) between multiple cells (eg, having a common schedule). Therefore, this would cause problems in 3GPP2 where such assumptions do not apply.

<u style="single">Two-point (PTP) transmission</u> Assuming that the application has a valid delay tolerance, the most efficient data transfer mode for two-point (PTP) transmission is Radio Line Control (RLC) Acknowledgment Mode (AM). For example, RLC acknowledgment mode (AM) is commonly used for packet-switched data transfer over dedicated logical channels. RLC operates in acknowledgment mode (AM) on a dedicated logical channel. As shown in Figure 5A, dedicated user traffic for one user service in the downlink direction is sent through a logical channel known as a dedicated traffic channel (DTCH).

In acknowledgment mode (AM), the reverse line is available for retransmission requests if the data is incorrect. RLC transmits the service data unit (SDU) and guarantees delivery to its peer entity by retransmission. If the RLC does not deliver the data correctly, the sending RLC user will be notified. Operations in RLC AM are generally more power efficient at the expense of added delay.

<u style="single">One-point to multi-point (PTM) transmission</u> A common traffic channel is a one-way channel that exists in the downlink direction and is used when transmitting information to either all terminals or a specific group of terminals. Both of these data transfer modes use a one-way common channel that does not have a configured reverse line channel.

It would be desirable to provide an architecture that allows MBMS services to be transparently switched between two-point (PTP) and one-point-to-multi-point (PTM) transmission modes. An architecture that allows switching between different radio line control (RLC) modes for good performance when transitioning between two-point (PTP) and one-point-to-multipoint (PTM) transmission modes. It would also be desirable to provide. This helps, for example, to reduce the required power.

Embodiments of the present invention will now be described with reference to the examples shown and described with reference to FIGS. 6-19. These features, among other things, help maintain service continuity between such transitions by using a new forward error correction (FEC) layer.

FIG. 6 is a diagram of an improved UMTS protocol stack with forward error correction (FEC) layers that can operate in forward error correction (FECd) mode and forward error correction (FECc) mode. When the user equipment (UE) changes from two-point (PTP) transmission to one-point-to-multipoint (PTM) transmission while maintaining service continuity, the forward error correction (FEC) layer is a single radio line control (RLC). ) Allows you to change the underlying radio line control (RLC) entity 152 from data transfer mode to another radio line control (RLC) data transfer mode. According to this embodiment, the FEC layer operates in the first mode (FECc) or the second mode (FECd). In one implementation, the first mode (FECc) utilizes the parity block and the second mode (FECd) operates without the parity block. The impact of changing between FECd and FECc modes is much lower than transitions between RLC modes and can be seamless so that data loss does not occur during the transition.

Forward error correction (FECc) mode utilizes external coding technology to protect user data. This is especially useful on common channels. Forward error correction (FECc) mode allows for features found in negative response mode (UM), such as framing (segmentation and concatenation) and sequence numbering that occur above the wireless line control (RLC) layer. As a result, the traditional negative response mode (UM) is performed in the forward error correction (FEC) layer, so the wireless line control (RLC) layer uses transparent mode (TM) for two-point (PTP) transmission. To do. This feature overlaps in wireless line control (RLC) acknowledgment mode (AM), but the gain from ARQ compensates for this duplication.

By placing a forward error correction (FEC) or external coding layer on top of the radio line control (RLC) layer, the sequence number is added to a layer unrelated to the radio line control (RLC) layer. With negative response transmission, the use of additional overhead, such as sequence numbers, allows the reorganization of Encoder Packets (EPs) and Protocol Data Units (PDUs) during asynchronous transmission of MBMS data. Since the sequence number is added to the layer above the radio line control (RLC), the sequence number is common to both two-point (PTP) and one-point to multi-point (PTM) transmissions, and thus one-point to pair. Series number continuity is maintained when the transition from multipoint (PTM) transmission to bipoint (PTP) transmission occurs. This allows the data to be reorganized to avoid duplication of data and / or missed data.

External coding is used in two-point (PTP) transmission, which potentially provides some power benefit to the system and / or reduces retransmission delays. Multimedia broadcast and multicast service (MBMS) data is fairly delay tolerant. In point-to-point (PTP) transmission, a feedback path is provided. It uses a more efficient radio line control (RLC) acknowledgment mode (AM) with the use of ARQ retransmissions, which is generally more efficient than the FEC method, where additional parity blocks are always sent when needed. Therefore, adding a parity block to the MBMS payload data is unnecessary on a dedicated logical channel, eg, between two points (PTP).

Figures 7A and 7B show examples of an access hierarchy protocol structure that includes forward error correction (FEC) layer 157 located above wireless line control (RLC) layer 150. The forward error correction (FEC) layer is described with reference to FIG.

Forward error correction (FEC) layer 157 receives user plane information 163 directly on the user plane radio carrier. Since the forward error correction (FEC) layer is located above the wireless line control (RLC) layer, the FEC protocol data unit (PDU) corresponds to the RLC service data unit (SDU). The FEC layer is preferably any SDU size (constrained to multiples of 8 bits), variable rate sources, out-of-series reception of packets from the lower layers, and reception of duplicate packets from the lower layers. Corresponds to. FEC PDU size is constrained to multiples of 8 bits.

As described in more detail below with reference to FIG. 9A, FEC layer 157 segments and concatenates high-level blocks of user data such as SDU. Each line is also referred to as an internal block. Each protocol data unit (PDU) contains overhead. Overhead includes a length indicator (LI) that marks the beginning of a protocol data unit (PDU) in which data from a particular block of user data, such as a service data unit (SDU), is located. A collection of PDUs includes an encoder packet (EP) or an "encoder matrix". The number of PDUs contained in a encoder packet (EP) depends, among other things, on the external code used. Packing each encoder "matrix" row into independent or separate transmission time intervals (TTIs) enhances physical layer performance. A short transmission time interval (TTI) duration is used to reduce the buffer load.

The coder packet (EP) then passes through an external code coder to generate a parity line. As described in more detail below with reference to FIG. 9A, FEC layer 157 provides external coding by providing the functionality of a Reed-Solomon (RS) encoder in UMTS Terrestrial Radio Connection Network (UTRAN) 20. Performs external coding by providing the functionality of a Reed-Solomon encoder within User Equipment (UE) 10.

The parity lines generated by the external encoder are added to the encoder packet (EP) and placed in the transmission buffer as a group of internal blocks. Each internal block has the information added to it to create a protocol data unit (PDU). Then, the PDU group is transmitted.

FEC layer 157 also allows playback of data belonging to one EP, even if different internal blocks are received from different cells. This is achieved through the transmission of the sequence number (SN) in the header of each protocol data unit (PDU). In one embodiment, the system frame number (SFN), which helps maintain data alignment for coded packets (EPs). Series numbers are discussed in more detail in this document with reference to, for example, Figures 10A and 10B.

FEC layer 157 also performs jamming and reconfiguration, transfer of user data, and forward delivery of higher layer PDUs, duplicate detection, and sequence number checking.

In the embodiments shown in FIGS. 6-7A, the forward error correction (FEC) layer 157 is between the packet data convergence protocol (PDCP) layer 156 and the wireless line control (RLC) layer 150 (eg, (BMC)). Shown at the same level as the layer and below the Packet Data Convergence Protocol (PDCP) layer). The internal block size matches the "gold" packet size of packets sent wirelessly, so by placing forward error correction (FEC) layer 157 just above wireless line control (RLC) layer 150. External code performance is optimized. Nevertheless, it should be understood that the forward error correction (FEC) layer is shown here for illustrative purposes only and is unrestricted. The Packet Data Convergence Protocol (PDCP) Layer 156 is used at the top of Forward Error Correction (FEC) Layer 157 because of its header compression capabilities. It should be noted that currently Packet Data Convergence Protocol (PDCP) Layer 156 is defined for two-point (PTP) transmission using dedicated logical channels. As shown in Figure 7, the forward error correction (FEC) layer is provided anywhere in the access layer above the wireless line control (RLC) layer or in the application layer. The forward error correction (FEC) layer may be below or above the packet data convergence protocol (PDCP) layer. If FEC is run at application layer 80, even if the "golden" packet size differs for the two, it can be applied equally to GSM and W-CDMA.

<u style="single">External code design</u> The new forward error correction (FEC) layer performs external coding based on user plane information. FIG. 8 is a diagram showing an information block 91 and an external code block 95 to illustrate the concept of the external code structure. FIG. 9A is a diagram showing an example in which the external code block structure is applied to multimedia broadcasting and multicast service (MBMS) data 91. External coding improves physical layer performance when broadcasting delay-tolerant content over the entire cell. External codes help avoid data loss, for example, during cell-to-cell transitions and between two-point (PTP) transmission modes and one-point-to-multipoint (PTM) transmission modes.

The external code block 95 is represented in the form of k protocol data block 91 and N-k parity line 93. In external block coding, the N-k parity line 93 is added to the information block 91, which creates the external code block 95, by segmenting, concatenating, and packing the data (including inserting overhead into the internal block). Data is aggregated into a large encoder packet or information block 91 by organizing user data into k payload lines by encoding the resulting information block 91 to generate. Parity block 93 adds redundancy information to information block 91. The individual lines of the external code block are then eventually transmitted during one or more transmission time intervals (TTIs). Redundancy information about a collection of protocol data units (PDUs) allows the original information to be reconstructed, even if some PDUs are lost during transmission.

Figure 9A shows a typical external code structure known as the Reed-Solomon (RS) block code. The Reed-Solomon (RS) code is used to detect and correct channel errors. The external code shown in Figure 9A is a systematic (n, k) block code, where each Reed-Solomon (RS) code symbol is 1-byte information defined by rows and columns. .. Each column contains a Reed-Solomon (RS) codeword. At least n parity blocks are required for n lost blocks to be restored. Therefore, as the number of parity blocks increases, the amount of memory required increases. In Reed-Solomon (RS) coding, N-k parity symbols are added to k-systemic symbols to generate codewords. In other words, the Reed-Solomon (RS) code [N, k] has k information or a "systematic" symbol and an N-k parity symbol. N is the length of the sign and k is the dimension of the sign. For each k information byte, the code creates an n-coded symbol, the first k of which is the same as the information symbol. Each line is "inner It is called "block)" and represents the payload for each transmission time interval (TTI). In a typical W-CDMA system, transmission occurs, for example, on a basic W-CDMA structure of 20ms frame (TTI). The parity symbol is the generation matrix G defined below._{k × N}Obtained from systematic symbols using: m_{1 × k} G_{k × N}= c_{1 × k} (Equation 1) m_{1 × k}= Information word = [m₀ m₁ M_k-1] (Equation 2) c_{1 × N}= Codeword = [c₀ c₁ C_N-1] (Equation 3) where m_i, c_iBelongs to any Galois field. For example, if the Reed-Solomon (RS) codeword symbol is 1 bit, a dimensional 2 (GF (2)) Galois field would be used to describe the decoding operation. In one embodiment, if the symbol is an octal number, a Galois field of dimension 256 GF (256) is used to describe the decoding operation. In this case, each information column consists of 1 byte per row. Each sequence of information is coded on a Galois field on dimension 256 GF (256) using the [N, k] Reed-Solomon (RS) code. If there are M-bytes per row, the external block is coded M times. Therefore, there are N * M bytes per external block 95.

<u style="single">Erase decryption</u> The external code structure allows for erasure correction. If the decoder knows which symbol is wrong, reconstructing the wrong systematic symbol requires a relatively small amount of calculation. A encoder packet (EP) or matrix refers to a complete set of data at the output of an external encoder. Redundancy information is taken column by column from each row, and each row transmitted has a CRC attached to it that must be inspected to ensure that the data was sent correctly. In the case of MBMS transmission, a CRC is used in each transport channel block to indicate if the internal block 91 is incorrect, and if the CRC fails, all symbols in the block are presumed to be incorrect. In the embodiment, if there is an error in an internal block 97, all the bits of that block are erased. The term "erasure" refers to each symbol belonging to the error block in which the CRC failed. Symbols that are not erased are considered correct. Ignoring the CRC undetected error probability, each Nx1 column contains the correct erased symbols.

The receive vector r is written as: r_{1 × N}= [c₀eec₃c₄ec₆c₈ C_N-1] (Equation 4) where e identifies the erasure.

Erase decoding allows corrections up to N-k error symbols. Since non-erasable symbols are considered correct, the error correction characteristics of RS codes are generally much better than those of common RS codes. The size of the CRC used in each internal block must be large enough to ensure that the undetected error probabilities do not exceed the remaining external block probabilities. For example, if a 16-bit CRC is used in the internal block, the remaining external block error rate low limit is 2^-16=1.5×10^-5Will. If the first k internal block is correct, the systematic symbol is the same as the information symbol, so RS decoding is not necessary.

It is noteworthy that as soon as a k block with a good CRC is received, the decryption of the external block is performed without waiting for the reception of all the blocks inside N. Modified generation matrix Ω for erasure decoding_{k × k} Is generated by erasing or removing all columns corresponding to unnecessary blocks Matrix G_{k × N}Obtained from, for example, the first good k-received symbol is used to identify the modified generation matrix. The original information word m is restored as:<maths num="1"><img id="000002" he="28" wi="159" file="JP5980838B2_D0001.tif" img-format="tif" img-content="drawing" /></maths>

The complexity of erasure decoding is reduced to the complexity of k × k matrix inversion. Thus, the use of RS erasure decoding greatly simplifies the computational complexity of RS decoding.

<u style="single">Impact of data jamming on external coding performance</u> As discussed below with reference to Figures 11-13, external coding results in very large overhead if the amount of clogging and overhead delivered over the air is limited by a particular external coding technique. Used with variable transmission rate data sources without. In the external coding technique discussed above, the data is packed into blocks of a certain size and a shortened Reed-Solomon code is executed across the blocks. The encoder packet data is packed into the TTI in at least two different ways as described with reference to FIGS. 9A and 9B.

FIG. 9B is a diagram showing the external code block structure of FIG. 9A in which a large number of rows are sent per transmission time interval (TTI). According to another embodiment of the invention, data from one line is transmitted in one TTI. In another embodiment, the data from one coded packet (EP) line is put into one TTI such that each TTI contains data from that coded packet (EP) line. Therefore, each line is transmitted in a separate W-CDMA frame or transmission time interval (TTI). Sending each row in one TTI will provide good performance. In Figure 9B, both k and n are separated by the number of rows per TTI, and the errors in the rows are fully correlated. When looking at EP error rate vs. TTI error rate, this makes a considerable difference.

FIG. 9C is a diagram showing the external block structure of FIG. 9A in which each row is sent in a large number of TTIs. Figure 9C illustrates sending each line of a coder packet over four TTIs (TTI0 to TTI3), but it is understood that in practice each line is sent over any number of TTIs. It should be. Since each column is a codeword of an external code, each of the four obvious transmission "phases" (TTI0 to TTI3) is equal to an independent external code. It would be necessary for all of these independent external codes to be correctly decoded in order for the entire packet to be restored.

10A and 10B are diagrams showing external code blocks generated by the forward error correction layer.

FECc mode is used on a common or one-point-to-multipoint (PTM) logical channel to construct an external code block 95 by adding a parity row or block 93 to the MBMS payload data 91. Each outer block 95 includes a plurality of inner blocks 91, 93. Identifying the sequence of internal blocks and their position with respect to the coded packet allows each available internal block to be placed in the correct position so that external decoding can be performed correctly. In one embodiment, each internal block includes a header 94 that identifies the internal blocks by the number of internal blocks m and the number of external blocks n. For example, the external block n includes a data portion 91 with an internal multimedia broadcast and multicast service (MBMS) payload block and a redundant portion 93 with an M- (m + 1) internal parity block. According to this example, the sequence number space is optimized for MBMS and is defined by some explicit sequence numbers, eg 0-127. The sequence number space is the reception where the same sequence number is caused by any kind of migration. gap) Must be large enough so that it does not appear later. The receiving UE must be able to determine the order of the internal blocks, even if some internal blocks are lost. If the UE loses more internal blocks that can be identified by the entire sequence number space, the UE will not be able to reorder the internal blocks correctly. The series number of the same internal block is the same across the FECd block and the FECc block. The FECd block does not include the redundant part 93 used in the FECc block. FECd and FECc entities use the same bit ratio wirelessly.

<u style="single">Sender</u> Transmission Forward Error Correction (FEC) entity 410 receives SDU receiving service data unit (SDU) buffer 412, segmentation and concatenation unit 414, Reed-Solomon (RS) coding external encoder 416, sequence. It includes a sequence number generator 418 that adds numbers to the coded PDU, a transmit buffer 420 that carries the PDU over logical channel 406, and a scheduling unit 422.

The service data unit (SDU) buffer 412 receives user data in the form of a service data unit on the radio carrier 402 as indicated by the arrow and stores the FEC SDU from higher layers. The receive buffer 412 communicates how much data is transmitted to the scheduling unit 422.

As mentioned above, since the source data-rate generally varies, the amount of time it takes to fill a coder packet (EP) generally varies. As explained with reference to FIG. 13, frame filling efficiency is improved by having flexibility in deciding when to start packing data. The amount of clogging introduced is reduced by delaying EP production as much as possible based on the jitter tolerance of the receiving FEC entity 430.

The planning entity 422 determines when to start coding. The scheduler 422 preferably determines how long it is possible to wait before a packet needs to be sent, based on the QoS characteristics (profile) for that particular service. Once the scheduler 422 proves that sufficient data has been accumulated or that the maximum acceptable packet transmission delay has been exhausted, it initiates the creation of coder packets (EPs). The segmentation and concatenation unit 414 divides the service data unit (SDU) into various rows and produces a length indicator (LI).

The scheduling unit 422 preferably determines the optimal size of the EP or protocol data unit (PDU) so that the SDU exactly fits the number of rows (eg, 12). Instead, the scheduler 422 selects the FEC PDU size from those composed of RRCs that will result in the least possible jamming, and the segmentation and concatenation function 414 k of the size of the SDU (PDU size-FEC header size). Request to format into blocks. This format changes. Examples of different forms of formatting are discussed below with reference to Figures 12 and 13. The total amount of data that can be considered will include the overhead that would be incorporated by the concatenation and segmentation function 414. To generate a encoder packet (EP), the scheduler 422 requires the concatenation and segment function 414 to create a kPDU of that size. This size contains rebuild information. In one embodiment, the PDU has a size that is a multiple of 8 bits, and the data in successive PDUs correspond to different symbols in the codeword.

The kPDU block is then executed via an external encoder 416 that performs Reed-Solomon (RS) coding. The external coder 416 encodes the data in the coder packet (EP) matrix by generating and adding redundancy or parity information to the coder packet (EP) matrix to create the external code block. The encoder encodes k rows of information of equal length and delivers the same size n-protocol data unit (PDU) to the lower sublayer. The first k block is the same as what it receives, and the next n-k block corresponds to the parity information.

The scheduler 422 also monitors the time array or relative timing of PTM streams and conducts transmissions to adjust the array of different logical streams. For example, the time sequence between the PTP and the PTM logical stream during the reconstruction is adjusted to benefit service continuity. Best performance is obtained when the streams are perfectly synchronized.

Different base stations (or different transmission modes: PTP, PTM) carry the same content stream, but their streams are out of sync. However, if the data streams have the same coded packet (EP) format, the information about each stream is exactly the same. Since the user device (UE) knows the relationship between the two streams, adding a sequence number to each external block allows the user device (UE) to combine the two streams.

The sequence number generator 418 appends a sequence number to the front of each block in the same sequence used in the encoder 416 to create the PDU. In an embodiment, the sequence number generator adds an 8-bit sequence number to the front of each external code block, for example, to generate a PDU. Additional overhead information is also added to the external code block. The sequence number space must be large enough to accommodate the bad time difference between streams. Therefore, in another embodiment, 20 sequence number spaces are used and at least 5 bits are provided in each header for sequence numbers. This header is added to the external code block after Reed-Solomon (RS) coding is done, so this "outer" header is not protected by the external code. Series numbers are also added, preferably for parity blocks, even if they are not sent. In one embodiment, the sequence number phase is aligned with the encoder packet boundary. A roll-over of sequence number will correspond to the reception of new coder packets.

<u style="single">Forward Error Correction (FEC) Header Format</u> As mentioned above, data stream synchronization is achieved by introducing a sequence number that contains information related to PDU ordering. In addition to reordering and duplication detection, sequence numbers allow the data from each source contained in the coded package to be rearranged. This sequence number clearly identifies the order in which each packet should be considered. This sequence number can form a "FEC header" that is added to both the information payload unit (PDU) and the parity block after it has been coded. The sequence number will not be protected by an external code as it is needed for decryption.

FIG. 14 is a diagram of an example of forward error correction (FEC) header format. To facilitate alignment of the data with the coder packet (EP), the sequence number is the hold part (R) 402, the coder packet (EP) part 404 that identifies the EP (EPSN), and the coder packet (IEPSN). ) Divided to include an internal encoder packet that identifies the location of a particular internal block within 406.

It is desirable for the FEC layer 400 to be able to interact with the wireless line control (RLC) mode. Both wireless line control (RLC) AM and wireless line control (RLC) UM require a service data unit (SDU) that is sized in multiples of 8 bits, so FEC Layer 400 should also stick to this requirement. Would be desirable. Since the external code for FEC layer 400 works by increasing the byte size of the data, the row size of the encoder packet (EP) will also need to be an integer byte. Therefore, the FEC header size 401 must also be a multiple of 8 bits for the FEC protocol data unit (PDU) in order to be acceptable for radio line control (RLC). In one embodiment where the forward error correction (FEC) header 401 is 1 byte, a hold portion (R) containing a single bit, a portion identifying an EP (EPSN) 404 containing 3 bits, and a code containing 4 bits. It has an IPE part that identifies the location of the PDU in the device packet (IEPSN) 406. In this embodiment, one PDU is sent per TTI, and the transmission timings of different cells are not expected to fluctuate by more than 100 ms, so an 8-bit sequence number is used.

Transmission buffer 420 stores PDUs until frames of data are accumulated. When a PDU is requested, the transmission buffer 420 sequentially transmits frames to the MAC layer on the wireless interface (Uu) via the logical channel. Then, the MAC layer communicates the PDU to the physical layer through which the PDU is eventually communicated with the UE 10 via the transport channel.

<u style="single">Receiver</u> Still referring to Figure 11, the receive forward error correction (FEC) entity 430 has a receive buffer / reordering / duplication detection unit 438, a sequence number removal unit 436, an external decoder 434 that performs Reed-Solomon decoding, and a rebuild. Includes unit / service data unit (SDU) transmission buffer 432.

The information line of the EP matrix corresponds to the PDU. To assist with external coding, the forward forward error correction (FEC) entity 430 accumulates several PDUs before initiating external coding. The user equipment (UE) buffers incoming protocol data units (PDUs) during decoding, even though it is necessary to decode the coded packets to achieve continuous reception.

Receive buffer 438 accumulates PDUs until all coded packets (EPs) are received or until the scheduling unit (not shown) is convinced that there are no more coded packet (EPs) retransmissions. Once it is determined that there will no longer be any data received for a coder packet, the missing PDU is identified as erasure. In other words, PDUs that do not pass the CRC check will be replaced with erasure in the decryption process.

Since some blocks can be lost during transmission, or different data streams have different delays, the receive forward error correction (FEC) entity 430 is potentially receive buffer / reorder / duplicate. The detection unit 438 detects duplicate reception blocks and reorders them. The sequence number is used in each FEC protocol data unit (PDU) to assist in reordering / duplication detection. The sequence number is used in receive buffer 438 to reorder the separately received data. Once the PDUs are reordered, the duplicate detection unit detects the PDUs in the coded packet (EP) based on their sequence number and removes any duplicates.

Then, the series number is removed. Since the sequence number is not part of the block sent to the Reed-Solomon (RS) decoder, the sequence number removal unit 436 removes the sequence number from the coder packet (EP).

The data is then passed to the external decryption function 434 to recover the missing information. The external decoder 434 receives the encoder packet (EP) and, if necessary, the Reed-Solomon (RS) decoder encodes by using the parity information to reproduce the incorrect or missing line. Decrypt a device packet (EP). For example, if all protocol data units (PDUs) containing information are not received correctly, or if less than k are correctly received from nPDUs, then up to the size of the parity PDU, protocol data units (PDUs), External decryption is done to restore the missing information PDU. At least one parity PDU will be available at the receiver whenever external decryption takes place. Decryption is not necessary if all protocol data units (PDUs) containing information are correctly received, or if less than k are correctly received from nPDUs. The Information Protocol Data Unit (PDU) is then delivered to Reconstruction Function 432.

The information line is then delivered to the rebuild unit / function 432, regardless of whether the external decryption was successful. Reconstruction unit 432 reconstructs or reconstructs the SDU from the information rows of the coder packet (EP) matrix using the length index (LI). Once the SDUs are successfully collected, the service data unit (SDU) transmission buffer 432 transmits the service data unit (SDU) on the wireless carrier 440 to deliver the SDUs to higher layers.

In forward error correction (FEC) entity 430, allowing the UE to delay decryption due to a time offset between different logical streams has the potential for data due to the system lacking synchronization between logical streams. Allows full use of out-of-line reception. This facilitates service during handoffs as well as migration between PTP and PTM. The algorithm that allows the UE to delay decoding by time offset between different logical streams is discussed with reference to Figure 15.

<u style="single">Coder Packet (EP) Choices: Fixed or Variable Line Size</u> The protocol data unit (PDU) does not have to be sent continuously at every transmission time interval (TTI), so the FEC or external code entity is not required when the protocol data unit (PDU) is constructed. Flexible. This will result in good frame filling efficiency and low packing overhead.

If desired, the external code entity can generate a payload at each transmission time interval (TTI). The service data unit (SDU) is received from the higher layers, so the protocol data unit (PDU) is built in real time. If there is not enough data to build the protocol data unit (PDU), RLC adds the jam.

<u style="single">Fixed line size encoder packet (EP)</u> When encoding SDU201-204, it is desirable to reduce the amount of clogging transmitted as much as possible.

In one embodiment, the row size of the encoder packet (EP) matrix 205 is fixed. The speculative knowledge of the row size of the coder packet (EP) matrix 205 allows the data to be aligned to their original configuration. Since the line size of SDU201-204 that will be sent internally is known in advance, transmission can start as soon as the data is received without waiting for how much data will be sent.

FIG. 12A shows an example of coding processing for creating the external code block 214 from the data units 201 to 204 in which the row size of the external code block 214 is fixed. In this example, the user data takes the form of multiple service data blocks (SDU) 201-204, including bits of any size block, the size of which depends on the particular application (video, audio, etc.). ..

Segmentation, concatenation and packing are done at the FEC level to allow transmission of any size FEC SDU. Concatenation is not absolutely necessary, but without it it would result in a significant reduction in high-level data processing.

Higher layers SDU201-204 are first formatted to this fixed PDU size. In this embodiment, the segmentation / concatenation function produces a fixed size internal block directed to the subscriber unit. At step 220, the group of internal blocks shows the internal blocks, the required degree of packing 208, and how many SDUs end in one line of the EP, Service Data Unit (SDU) 201. Segmented and concatenated to be part of the encoder packet matrix 205, including the length indicator (LI) 206 used to point to the end of ~ 204. The external encoders discussed below use these internal blocks to create redundant blocks.

In wireless line control (RLC), each service data unit (SDU) is identified by a length index (LI) compared to a protocol data unit (PDU) rather than a service data unit (SDU). Indicates the end of. This helps reduce overhead, as the PDU size is generally smaller than that of the service data unit (SDU). For example, the length index (LI) is used to indicate the last octal number (octet) at the end of each FEC service data unit (SDU) in the payload data unit (PDU). The "length indicator" is set to the number of octals between the end of the FEC header and the last octal of the FEC SDU segment. The length indicator (LI) is preferably included in the PDU referenced by the length indicator (LI). In other words, the length index (LI) preferably refers to the same payload data unit (PDU) and is preferably in the same order as the FEC SDU referenced by the length index (LI).

When an external block is received, information such as length index (LI) is used to inform the receiver where the service data unit (SDU) and / or jamming starts and ends. To.

Since bits in the FEC header cannot be used to indicate the presence of a length indicator (LI), the FEC header adds a fixed header in the payload that indicates the presence of a length indicator (LI). The internal header or LI provides all the information needed to build SDU201-204. The LI is included in the PLC-PDU it references. The presence of the first LI is indicated by a flag contained in the PLC-PDU sequence number header. The bits in each LI are used to indicate the extension. A 1-byte length indicator (LI) that indicates that the previous SDU was insufficient to meet the last PDU to allow the length of the length indicator (LI) to be exchanged for the FEC PDU size. ) Is introduced with a new specific value. Length index (LI) existence bits are implemented in various ways, two of which are discussed below.

In one embodiment, the length indicator (LI) presence bits are provided in each protocol data unit (PDU). For example, one byte is added to the beginning of each coder packet (EP) line, and the bits in the byte indicate the presence of LI. The entire first byte of each protocol data unit (PDU) is reserved for this "presence bit". To accommodate this existing bit, the length index is shortened by one bit. Providing an existing bit in each packet unit (PDU) allows the SDU to be decrypted if EP decryption fails, even if the first PDU is missing. This results in a low residual error rate. Providing existing bits in each PDU allows real-time concatenation / segmentation.

In another embodiment, the length indicator (LI) presence bit is provided in the first PDU. Instead of adding overhead at the beginning of each PDU, the presence bits of all k information PDUs are added to the beginning of the first PDU in the EP. Providing present bits at the beginning of a coder packet (EP) results in less overhead when having a large SDU and / or small PDU.

After segmentation and concatenation, EP205 contains several rows occupied by multiple service data units (SDU) 201-204 and at least one of the jam blocks. The row size of the external block is a peak data for each row. It is designed to be transmitted during the transmission time interval (TTI) at rate). The service data unit (SDU) is generally not coordinated with the amount of data sent during the transmission time interval (TTI). Thus, as shown in FIG. 12A, the second and fourth SDU 202, 204 do not meet the transmission time interval (TTI) of the first and second rows of the EP, respectively. In this example, the EP has 12 rows available for the data, and 4SDU201-204 are packed into the first three rows of these 12 rows. The remaining rows of EP205 are occupied by jam block 208. Thus, in the second SDU202, the first part of the second service data unit (SDU) 202 starts in the first line of the "information block" and the second part of the second SDU202 is in the second line. It is divided so that it ends with. Similarly, the third SDU is split so that the first part of the third service data unit (SDU) 203 starts on the second line and the second part of the third SDU 203 ends on the third line. It must be. The fourth service data unit (SDU) 204 fits within the third row and the rest of the third row is filled with packing block 208. In this example, the encoder packet (EP) 213 is usually composed of a jam 208.

The encoder uses EP to generate redundancy or parity information. At step 240, the encoder encodes the intermediate packet matrix 205, which is encoded by adding the external parity block 214 to generate the external code block 213, which is 16 blocks in length. The encoder extracts 8-bit data from each column of each block to create the resulting data 210. The Reed-Solomon (RS) encoder encodes the resulting data 210 to obtain four lines of redundancy or parity information 212. Parity information 212 is used to generate the external parity block 214 that is added to the EP matrix 205 to generate the 16 blocks of external code block 213.

FIG. 12B shows an example of information transmitted wirelessly in the example discussed above. At step 260, after adding additional overhead, including sequence numbers, to each column of EP205, 16 blocks of external code block 213 are transmitted wirelessly as Protocol Data Unit (PDU) 214. Sufficient or entire coded packet (EP) 213 matrix is not transmitted by Protocol Data Unit (PDU) 214 sent over the downlink. Rather, the protocol data unit (PDU) contains information bits 201-204 and the length index (LI) 206 of the coder packet (EP) matrix 213. Since the coder packet (EP) matrix 213 rows size is fixed and therefore known to the receiver, it is not necessary to actually send the jamming 208 wirelessly. Since the jamming value is known, the jamming information 208 is not transmitted on the downlink, so there is no need to transmit the jamming information 208. For example, if the jam consists of a series of known bits, such as all 0s, all 1s, or alternating patterns of 0s and 1, the receiver is nominally coded packet (EP) up to 213 lines of protocol data. -Unit (PDU) 214 can be packed. Therefore, instead of choosing a PDU size equal to the EP row size during transmission, the smallest available EP size that carries all the information bits 201-204 and the rebuild overhead (eg, LI) is utilized.

Although the row size of the encoder matrix is fixed, the FEC PDU size is selected from a set in each transmission so that each contains all the information parts of one encoder matrix row (excluding clogging). Will be. When receiving a PDU smaller than the row size of the encoder matrix, the UE can pack up to that size with a known bitstream. This allows the internal block size to remain fixed without increasing the load on the aerial interface. Using a fixed line size, the coder packet (EP) 213 needs to remove the need to wait until all the data is available before starting to transmit the protocol data unit (PDU) and also send a jam. Remove sex.

If the above algorithm is implemented to handle variable rate transmission, a transmission rate equalization technique is used in which all coder packet matrices have a constant size. Smaller PDUs will be used when jamming forms part of a PDU. The jam consists of a specific bitstream and is located at the end of the data. In the receiver, the size of the block received from the lower layer is equalized to the base-line size by adding a jam at the end.

If a given bitstream is used for packing, this packing will not be transmitted wirelessly. The receiver does not need to know the actual coder packet line size unless the receiver needs to perform external decryption. Basic SDU reconstruction does not require knowing the amount of jamming at the end of the PDU. External decoding is not required if all PDUs containing information from the first k-coder packet (EP) line are received. In contrast, if at least one PDU containing information from the first k-code packet (EP) line is missing, then at least one PDU containing data from the parity line is required. Parity lines are generally uncluttered, so the size is used as a reference for the actual coder packet size that needs to be assumed.

<u style="single">Variable line size encoder packet (EP)</u> FIG. 13 shows a coding process for creating an external code block 313 with a variable row size.

This embodiment of the invention relates to flexible external block coding of data sent over an aerial interface. This coding process results in less clogging being sent so that the frame filling efficiency is increased. Lines of coder packet (EP) 305 are variable size, and differently sized external blocks are sent for each transmission time interval (TTI). Preferably, the row size of the encoder packet (EP) 305 varies so that the SDU exactly fits the number of rows in the encoder packet (EP) matrix 305 (eg, 12). In this example, the FEC layer must wait for all available data before making the EP so that the FEC layer can determine the optimal row size. The row size is chosen from several different sizes based on the amount of data available to limit clogging. The row size of a coder packet (EP) is associated with the set of PDU sizes configured for S-CCPCH. Depending on the amount of data available when the encoder packet 305 needs to be generated, the minimum packed row size is selected. By reducing the size of the external block 313 so that the block size is smaller at each frame, less data is sent over the same TTI period, so the data is sent at a reduced transmission rate. Using the variable row size of the coder packet (EP) 305 helps to stabilize the required power over the entire transmission of the coder packet (EP) and also to take advantage of the less parity overhead 314. This embodiment works well for one-point-to-multipoint (PTM) transmission in systems such as W-CDMA where the size of the transport block sent at each transmission time interval (TTI) varies depending on the intrinsic radio protocol.

In step 320, the plurality of service data units (SDU) 201-204 are coded packets used by the length indicator (LI) 206 to point to the end of service data units (SDU) 201-204. (EP) Segmented and concatenated to generate matrix 305. The length indicator (LI) is included in the last column where each service data unit (SDU) ends.

At step 330, redundancy or parity information is generated column-wise by extracting 8-bit data from each data block, and the resulting data 310 is a Reed-Solomon (RS) code to obtain parity information 312. It is sent to the vessel. Since the rows of the encoder packet (EP) matrix 305 are smaller, less redundancy information is generated.

In step 340, the parity information 312 produces an external parity block 314 that is attached to the 12-block coder packet (EP) matrix 305, thereby producing an external code block that is 16 blocks long in this example. The encoding continues as it is used for. Since the entire external code block 313 is occupied by either the SDU, the length index (LI) 206, and / or the redundancy information 314, this embodiment avoids jamming transmissions that improve transmission efficiency. In this particular example, no jamming was required. However, it should be understood that some packing is required despite the reduced amount of packing, as the number of PDU configuration sizes is limited in some cases. This results in high frame filling efficiency and also allows constant power to be maintained throughout the entire coder packet (EP). This is desirable in CDMA systems that utilize power control techniques.

Although not shown, the transmission of PDUs over the air occurs similar to what was discussed above for step 260 in Figure 12.

FIG. 11 is an example of forward error correction (FEC) layer 400 with RLC negative response mode (UM) + entity (RLC UM +) provided over external coding or wireless line control (RLC). In general, wireless line control (RLC) provides framing for higher layers. Here, the FEC layer above the wireless line control (RLC) layer is framed.

The external coding layer 400 includes a transmission forward error correction (FEC) entity 410 that communicates with a receive forward error correction (FEC) entity 430 on the radio interface (Uu) 404 via logical channel 408.

<u style="single">Reordering / Duplicate detection</u> FIG. 15 is a reordering protocol or algorithm that allows mobile station 10 to delay decoding by a time offset between different logical streams.

Forward Error Correction (FEC) entity 430 uses a sequence number to locate a PDU in the EP matrix. For example, part of the sequence number (PSN) identifies the location of the encoder packet (EP).

This algorithm, at best, assumes that data from two coder packets (EPs) will be received before decoding begins. In the description below, the coder packet (EPd) is the next coder packet (EP) in the sequence to be decoded, and the coder packet (EPb) is the coder packet (EP) being buffered. The encoder packet (EPb) follows the encoder packet (EPd). UE implementations that require full coder packet transmission time to perform RS decoding will need to be double buffered to be able to decode series packets. Therefore, the UE stores at least the maximum size rows n + k of the code matrix (k and n are the total number of rows including the number of information rows and parity, respectively). UEs with faster decoding engines are lower than n + 1 but can reduce this requirement. For example, if the UE has a certain amount of buffer space (XtraBffr) beyond the amount required to receive sequence packets based on its decryption capabilities, and if a 64kbps stream is expected. Delaying decryption by 100ms without increasing the computational demand would require an 800 byte increase in buffer size.

At block 1410, it is determined whether a new forward error correction (FEC) protocol data unit (PDU) has been received. If no new forward error correction (FEC) protocol data unit (PDU) is received, processing resumes at block 1410. If a new forward error correction (FEC) protocol data unit (PDU) is received, does block 1420 belong to the sequence in which the new forward error correction (FEC) protocol data unit (PDU) is decoded? Whether or not it is determined is made.

If the forward error correction (FEC) protocol data unit (PDU) does not belong to the sequence to be decoded, block 1421 is buffering a new forward error correction (FEC) protocol data unit (PDU). Whether or not it belongs to a coder packet (EPb) is determined. If the forward error correction (FEC) protocol data unit (PDU) does not belong to the buffered coded packet (EPb), the protocol data unit (PDU) is dropped at block 1440. If the forward error correction (FEC) protocol data unit (PDU) belongs to a buffered encoder packet (EPb), then in block 1423 the protocol data unit (PDU) is in the EPb at the relevant location. Added to the buffer. At block 1425, it is determined whether the amount of data for EPb exceeds XtraBffr. If it is determined in block 1425 that the amount of data for EPb does not exceed XtraBffr, processing resumes in block 1410. If the amount of data for EPb exceeds XtraBffr, in block 1428 the transmission entity attempts to deliver the full SDU from EPd. Then, at block 1430, the remaining EPd is cleared from the buffer, and at block 1434 EPb is set to EPd.

If forward error correction (FEC) protocol data unit (PDU) belongs to EPd in block 1420, then in block 1422 the protocol data unit (PDU) is added to the EPd's buffer at the relevant location. At block 1424, it is determined whether the buffer has individual PDUs for k with respect to EPd. If the buffer does not have k individual PDUs for EPd, processing resumes at block 1410. If the buffer has k individual PDUs for EPd, at block 1427, the decoder will perform an external decryption for EPd, and at block 1428, the transmission entity will deliver the full SDU from EPd. Try. Then, at block 1430, the remaining EPd is cleared from the buffer, and at block 1434, EPb is set to EPd.

Figure 16 shows the time relationship between external code blocks received by the mobile station for one-point-to-multipoint (PTM) transmission from cell A (98) and another one-point to multipoint (99) from cell B (99). It is a figure which shows as a mobile station transition between receiving (PTM) transmission. Some forms of Figure 16 are Grilli et al. US Pat. No. US-2004-0037245-A1 filed August 21, 2002, and Willengger et al. US Pat. No. US-2003-0207696 filed May 6, 2002. -Discussed further in A1 and they are incorporated here by reference throughout them.

The scenario depicted assumes the requirements of a UMTS Terrestrial Radio Connection Network (UTRAN) 20 and User Equipment (UE) 10. For example, if UTRAN20 sends content across cells using the same external block coding, the same numbering must be used for blocks carrying the same data or payload in adjacent cells. External blocks with the same number are transmitted in a relatively time-aligned manner. The largest misalignment of PTM transmission across cells is controlled by the Radio Network Controller (RNC) 24. UTRAN20 controls delay jitter due to point-to-multipoint (PTM) transmission across cells. UE10 must be able to decrypt the external block when the next block is being received. Therefore, the buffer space in the UE should preferably be adapted to at least two external blocks 95A-95C, as the memory of one external block is needed to accumulate the current external blocks. Memory must also be able to accumulate internal blocks of "rows" in order for external blocks to compensate for inaccuracies in time alignment across base station 22 during Reed-Solomon (RS) decoding. ..

In cell A (98), during the transmission of the external block n (95A), the transition occurs during the transmission of the second internal multimedia broadcast and multicast service (MBMS) payload block. The slope of arrow 96, which illustrates the transition of user device (UE) 10 from cell A (98) to cell B (99), is not horizontal, as some time elapses during the transition. By the time user device (UE) 10 reaches cell B (99), the fifth block of the multimedia broadcast and multicast service (MBMS) payload block is being transmitted. Therefore, the user equipment (UE) 10 lacks the second to fourth blocks from the time elapsed between the time misalignment and transition of each transmission. If enough blocks are received in cell B (99), the external block n (95A) is still decoded because the parity block is used to reconstruct the missing block.

Then, during the transmission of external block n + 2 (95C), user equipment (UE) 10 undergoes another transition from cell B (99) to cell A (98), which is external block n + 2 (95C). ) Fifth internal multimedia broadcasting and multicast service (MBMS) payload block. In this situation, a few internal blocks are lost during the migration and the external blocks are still regenerated.

The use of external code blocks helps reduce the likelihood of any service interruption. To ensure that error recovery works, the same blocks must be sent on each transmission line, which means that parity blocks should be constructed in the same way on each transmission line. (Because it is broadcast transmission, the multimedia broadcasting and multicast service (MBMS) payload block is always the same for each transmission line.) Forward error correction (FEC) at the upper application layer 80 is encoded. It is done at forward error correction (FEC) layer 157 and is therefore the same for each external block, which helps ensure that the parity blocks are the same on each transmission line. In contrast, if the coding is done, for example, in the lower layers of the individual radio line control (RLC) entities 152, some adjustment is required as the parity blocks are different in each transmission line. ..

<u style="single">Transition from one-point to multi-point (PTM) to two-point (PTP)</u> FIG. 17 is a diagram showing the time relationship between external code blocks received by mobile station 10 when a transition occurs between one-point to multipoint (PTM) transmission and two-point (PTP) transmission. The method shown in FIG. 17 applies to systems that utilize two-point (PTP) transmission, such as W-CDMA and GSM systems.

The embodiments of the present invention relate to forward error correction by adding parity information or blocks to the internal MBMS "payload" or data blocks during PTM transmission. Each external code block transmitted in PTM transmission includes at least one payload block and at least one internal parity block. The error correction capability of the external code block shifts, for example, when the UE moves from one cell to another, or when the MBMS content delivery changes from a PTM connection to a PTP connection in the same service cell. Make sure to significantly reduce and eliminate the loss of MBMS content or "payload" between.

As mentioned above, some cells transmit to subscriber 10 using either PTP or PTM transmission techniques. For example, if the demand in that cell for a service falls below a certain threshold, then in normal PTM transmission mode the cell transmitting the broadcast service sets up a dedicated channel in PTP mode (only one subscriber 10). Select to transmit. Similarly, a cell that normally transmits content to individual subscribers on a dedicated channel (PTP) decides to broadcast the content to a large number of users on a common channel. In addition, one cell will transmit content in PTP transmission mode, while another cell will transmit the same content in PTM transmission mode. A transition occurs when the mobile station 10 moves from one cell to another, or when the number of subscribers in a cell changes from PTP to PTM, or vice versa. The reverse is also true.

During the two-point (PTP) transmission of the external block n (95A), the transition occurs during the transmission of the fourth internal multimedia broadcast and multicast service (MBMS) payload block. The slope of arrow 101, which illustrates the transition of the user equipment (UE) from one-point to multipoint (PTM) transmission to two-point (PTP) transmission, is not horizontal because some time elapses during the transition. When the transition from PTM101 to PTP occurs, the radio transmission bit ratio remains approximately the same. Two-point (PTP) transmissions typically have a bit error rate of 1 percent or less (eg, there is an error of 1 or less for every 100 payload blocks during transmission). In contrast, one-point-to-multipoint (PTM) transmissions assume higher bit error rates. For example, in one embodiment, the base station generates external blocks once every 16 transmission time intervals (TTIs), of which 12 TTIs are occupied by payload blocks and 4 TTIs are occupied by parity blocks. The maximum number of block errors allowed must be 4 internal blocks out of 16 (12 basic blocks + 4 parity blocks). Therefore, the maximum permissible block error rate would be 1/4.

When a mobile station transitions from one-point to multipoint (PTM) transmission to two-point (PTP) transmission (101), some internal blocks are lost. On average, the percentage of retransmit blocks is generally high, assuming that one-point-to-multipoint (PTM) and two-point (PTP) transmissions have approximately the same bit ratio at the physical layer (LI). Being less than or equal to the percentage of parity blocks, PTP transmission allows MBMS payload blocks to be sent faster than PTM transmission. In other words, statistically speaking, the number of parity blocks is much higher than the number of wireless line control (RLC) retransmissions (Re-Tx), so two-point (PTP) transmission is one-point to many-point (PTP) transmission. Generally much faster than PTM) transmission. Since transition 101 is from one-point-to-multipoint (PTM) transmission to generally much faster two-point (PTP) transmission, when user device 10 transitions to two-point (PTP) transmission, multimedia broadcasting and The first block of multicast service (MBMS) payload data is being transmitted. Therefore, no block is lost in the time misalignment of each transmission or the time elapsed during the transition 101. Therefore, when transitioning from one-point-to-multipoint (PTM) transmission to two-point (PTP) transmission, the lost payload block is the current external block once the PTP line is established on the target cell. It is created by simply restarting from the beginning. The network compensates by initiating PTP transmission at the beginning of the same external block, i.e. the first internal block. The network then recovers from the delay introduced by the migration with fast delivery of complete external blocks. Reducing data loss during migration reduces the interruption in delivery of MBMS content caused by such migration.

Then, during PTP transmission of external block n + 2, user equipment (UE) 10 undergoes another transition 103 to one-point to multi-point (PTM) transmission mode. In Figure 12, this transition 103 from point-to-point (PTP) to point-to-multipoint (PTM) occurs at the last internal multimedia broadcast and multicast service (MBMS) payload block in external block n + 2. In this situation, many internal multimedia broadcast and multicast service (MBMS) payload blocks in external block n + 2 have already been sent except for the last internal block. FEC is commonly used in situations where feedback is not available. The use of FEC does not seem to be beneficial, as PTP transmission utilizes a dedicated channel and therefore has feedback capability over the reverse line. To minimize or eliminate data loss in cross-transition, UMTS Terrestrial Radio Connection Network (UTRAN) 20 preferably reclaims all internal blocks that would be lost during the transition to PTM transmission. In addition, it depends on the low residual block error rate of RLC acknowledgment mode (AM) in PTP transmission. In other words, standard Layer 2 retransmissions are used to retransmit any packet for which an error is detected in the original transmission. Therefore, as shown in FIG. 17, parity blocks are not required for PTP transmission. If an error is present in the payload block during bi-point (PTP) transmission, the wireless line control (RLC) layer requires the retransmission of any error block, so the external block is still decoded. That is, when there is an error during PTP transmission, mobile station 10 requests retransmission (re-TX), or when all blocks are correct, retransmission is not performed and transport format 0 (TF0) is used. To. External coding is preferably done at layer 2 of the protocol stack so that the size of each internal block 97 fits exactly one transmission time interval (TTI), as this increases coding efficiency.

If forward error correction (FEC) external coding is done at an upper layer of the protocol stack, such as the application layer, then the parity block is a transmission method (two-point (PTP) or one-point-to-multipoint (PTM)). Will be sent regardless. Therefore, a parity block will also be added to the point-to-point (PTP) transmission.

As mentioned above, the use of parity blocks in PTP transmission is not necessary, as more efficient retransmission techniques are used instead of forward error correction. Parity blocks are preferably not transmitted in PTP transmission, so delivery of a complete external block is on average faster than PTM, assuming the same bit ratio wirelessly. Since two-point (PTP) transmission is expected for one-point to multi-point (PTM) transmission, this allows the UE to compensate for the interruption caused by the transition of PTM to PTP. The user equipment (UE) can (1) receive internal blocks in either two-point (PTP) transmission in a new cell or after migration, and (2) one-point-to-multipoint (2) in the old cell or before migration ( PTM) Regenerates an external block by combining it with an internal block received in transmission. The user device (UE) combines the internal blocks received before the migration and the internal blocks received after the migration that belong to the same external block. For example, user equipment (UE) 10 displays an internal multimedia broadcast and multicast service (MBMS) payload block in external block n + 2 received via two-point (PTP) transmission, one-point-to-multi-point. Combine with the internal multimedia broadcast and multicast service (MBMS) payload block in the external block n + 2 and parity block received via (PTM) transmission. The UMTS Terrestrial Radio Connection Network (UTRAN) 20 facilitates this process by slightly "anticipating" the transmission of external blocks to all users who receive MBMS content from the PTP line for transmission over the PTM line.

Since UTRAN anticipates the transmission of external blocks for PTM transmission, a "seamless" transition from PTP to PTM is possible. As a result, delivery of MBMS content across cell boundaries and / or between different transmission methods such as PTP and PTM is also "seamless". This "time anticipation" is represented by the number of internal blocks. When user equipment (UE) 10 transitions to PTM transmission, even if the communication line does not exist during the transition time, user equipment (UE) 10 does not compromise the QoS of MBMS reception and the internal block "time". Waste up to "expectations". Once the UE initiates MBMS reception directly in PTP, UTRAN20 slowly transmits external blocks by avoiding empty internal blocks (TF0) until the expected number of internal blocks "time expected" is reached. UTRAN will apply the "time forecast" immediately at the beginning of the PTP transmission. From that point on, UTRAN keeps the "time forecast" constant.

For one-point-to-multi-point (PTM) transmission, the UE-specific feedback information available in the radio line controller (RNC) is unreliable. For point-to-point (PTP) transmission, UE10 will inform the RNC of the number of last external blocks correctly received prior to migration. This will apply to any transition to PTP (from PTM or from PTP). If this feedback does not appear to be acceptable, UTRAN 20 estimates the last external block that was probably received by user device (UE) 10 prior to state transition. This estimate is based on knowledge of the greatest predictable time inaccuracy during obvious cell transmissions, and on external blocks that are currently being sent or will be sent soon in the target cell. Let's go.

Forward error correction (FEC) is performed so that any blocks lost during the transition are regenerated. This results in a "seamless" migration by reducing the likelihood that content will be lost during the migration. This technique causes a transition from two-point (PTP) to one-point to multi-point (PTM) transmission when the same external block is being transmitted from each source, which is generally the duration of the external block. It is assumed that it will occur if there is a period.

The amount of memory in UE10 is an antinomy with the accuracy of time alignment of PTM transmissions across adjacent cells. By relaxing the memory requirements in the user device (UE) 10, the time accuracy of PTM UTRAN transmission is increased.

Figure 18 shows during the transition or relocation between two-point (PTP) transmission from wireless network controller (RNC) A and two-point (PTP) transmission from wireless network controller (RNC) B. It is a figure which shows the time relationship between the external code blocks received by a mobile station. The term "RNC" is used interchangeably with the term "base station controller (BSC)". During the "relocation", the user equipment (UE) 10 from the two-point (PTP) transmission of the content stream in the area controlled by the first RNC A (124) to the second RNC B (224). ) Transitions to two-point (PTP) transmission of the content stream in the area controlled by. Retransmission (re-Tx) is used to compensate for any missing MBMS payload blocks. The direct transition from two-point (PTP) transmission between cells to two-point (PTP) transmission is similar to the Release '99 soft or hard handover. Goal RNC without cooperation between two RNCs A and B A (124) must calculate all the last external blocks received by UE10. This estimate will be based on the timing of MBMS content received by RNC24 on Iu interface 25. When using PTP transmission, the RNC24 creates an initial delay and no part of the MBMS content will be lost without the need for lossless SRNS relocation.

Although the flow charts are drawn in sequence for understanding, one of ordinary skill in the art will appreciate that certain steps are performed in parallel in actual implementation. Unless otherwise indicated, method steps can be replaced without departing from the scope of the invention.

Those skilled in the art will appreciate that information and signals are represented using a variety of different techniques and techniques. For example, data, instructions, instructions, information, signals, bits, symbols, and chips cited throughout the above description are represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. Will be done.

Those skilled in the art will appreciate that the various exemplary logical blocks, modules, circuits, and algorithmic steps described in connection with the embodiments disclosed herein can be performed as electronic hardware, computer software, or a combination of both. Will understand further. To articulate this hardware and software compatibility, various exemplary components, blocks, modules, circuits, and steps have generally been described above with respect to their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and design constraints imposed on the entire system. A skilled technician may be able to perform the functionality described in various ways for each particular application, but decisions of such practice should not be construed as departing from the scope of the invention.

The various exemplary logical blocks, modules, and circuits described in connection with the embodiments disclosed herein are general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), and field programs. Performed or performed by a possible gate array (FPGA) or other programmable logic device, individual gate or transistor logic, individual hardware components, or any combination thereof designed to perform the functions described herein. .. The general purpose processor may be a microprocessor, but instead it may be any conventional processor, controller, microcontroller, or state machine. Processors are also implemented as a combination of computing devices, such as a combination of DSP and microprocessor, multiple microprocessors, one or more microprocessors connected to a DSP core, or any other configuration thereof.

The operations of the methods or algorithms described in connection with the embodiments disclosed herein are incorporated directly in hardware, in software modules executed by a processor, or in a combination of the two. Software modules reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, replaceable disks, CD-ROMs, or other types of storage media known in the art. A typical storage medium is connected to the processor so that the processor can read information from the storage medium and write the information to the storage medium. Alternatively, the storage medium may be integrated with the processor. The processor and storage medium may reside in the ASIC. The ASIC may be stationed at the user terminal. Alternatively, the processor and storage medium may reside as separate components in the user terminal.

The previous description of the disclosed examples is provided to allow one of ordinary skill in the art to make or use the present invention. Various changes to these embodiments will be immediately apparent to those skilled in the art and the general principles defined herein can be applied to other embodiments without departing from the spirit or scope of the invention. For example, the wireless connection network 20 is implemented in a GSM / GPRS system using a general-purpose terrestrial wireless connection network (UTRAN) aerial interface instead, but the connection network (access network) is GSM / EDGE (GERAN). Or, in the case of an intersystem, it includes cells of the UTRAN aerial interface and cells of the GSM / EDGE aerial interface. As such, the invention is not intended to be limited to the examples presented herein, but should be given the broadest scope compatible with the principles and novel features disclosed herein.

Part of the disclosure of this patent document includes material subject to copyright protection. Because patent documents are published in patent files or records from the Patent and Trademark Office, the copyright owner does not object to facsimile reproduction of either the patent document or the patent specification, but in all other cases all copyrights. Withhold rights.<u style="single"> The inventions described in the claims of the original application of the present application are described below.</u><u style="single">[C1]</u><u style="single"> Frame the first type of information line containing the payload data in the first format on the radio carrier from the first source to generate the second type of information line,</u><u style="single"> Encoding the second type of information line to generate a redundant information line containing a parity block,</u><u style="single"> Adding the redundant information line to the second type of information line in order to generate an external code block containing the payload data line in the second format and the parity block.</u><u style="single"> Adding overhead information to each line of the external code block, where the overhead information includes a sequence number, and</u><u style="single"> Sending the external code block to the wireless link control layer</u><u style="single"> How to communicate information on a channel, including.</u><u style="single">[C2]</u><u style="single"> The method according to [C1], further comprising receiving the external code block from the first source.</u><u style="single">[C3]</u><u style="single"> When the radio transmitter undergoes a transition, it receives a second packet from a second source that is identical to the second type information line, and</u><u style="single"> Using the sequence number to realign the external code block with the second packet.</u><u style="single"> The method described in [C2], further comprising.</u><u style="single">[C4]</u><u style="single"> The method according to [C1], wherein the second type of information includes payload data in a second format and, in some cases, padding information.</u><u style="single">[C5]</u><u style="single"> The method according to [C1], wherein the sequence number provided prior to encoding allows the wireless link control layer to change modes if the wireless transmitter undergoes a transition.</u><u style="single">[C6]</u><u style="single"> The method according to [C1], wherein the coding involves external coding and is performed independently of the wireless link control layer.</u><u style="single">[C7]</u><u style="single"> The method according to [C1], wherein the channel is a logical channel common to one direction.</u><u style="single">[C8]</u><u style="single"> The method according to [C7], wherein the channel is a unidirectional downlink channel.</u><u style="single">[C9]</u><u style="single"> The method described in [C8], where a common logical channel carries information that is broadcast to one or more terminals.</u><u style="single">[C10]</u><u style="single"> A method of transmitting a first external code block and a second external code block to a wireless transmitter.</u><u style="single"> Sending the first block with at least one data row and at least one redundant row, where each row has overhead information including a sequence number and the second block consists only of data rows.</u><u style="single"> If the radio transmitter undergoes a transition, use the sequence number to align the first block with the second block.</u><u style="single"> How to include.</u><u style="single">[C11]</u><u style="single"> Wireless link control layer and</u><u style="single"> With the forward error correction layer arranged on the wireless link control layer</u><u style="single"> Including</u><u style="single"> The forward error correction layer receives the first type of information on the radio carrier before the first type of information reaches the radio link control layer.</u><u style="single"> The forward error correction layer is a frame of equal size of the first type of information before the first type of information reaches the wireless link control layer in order to generate the second type of information. Frame composition inside,</u><u style="single"> The forward error correction layer uses the second type of information to generate a line of redundant information that is added to the second type of information to generate an external code block.</u><u style="single"> The forward error correction layer adds a sequence number to each frame before transmitting to the wireless link control layer.</u><u style="single"> Protocol structure for communication systems.</u><u style="single">[C12]</u><u style="single"> The protocol structure according to [C11], wherein the source is the first source and the external code blocks are transmitted on a common logical channel.</u><u style="single">[C13]</u><u style="single"> The protocol structure according to [C12], wherein the sequence number allows the second type of information to be rearranged with other second type of information from the second source during migration.</u><u style="single">[C14]</u><u style="single"> A method of encoding information before transmitting it on a common channel in a system that includes a wireless link control layer.</u><u style="single"> Receiving the information from the wireless carrier and</u><u style="single"> External block coding of the information before passing it to the wireless link control layer</u><u style="single"> How to include.</u><u style="single">[C15]</u><u style="single"> The information contains content and the external block coding</u><u style="single"> Organize the content into data blocks</u><u style="single"> Encoding the data block to generate a parity block,</u><u style="single"> Including adding the parity block to the data block to generate a encoder packet.</u><u style="single"> The parity block was configured to be used to reconstruct any data block lost during transmission.</u><u style="single"> The method described in [C14].</u><u style="single">[C16]</u><u style="single"> The method according to [C15], further comprising adding overhead information to each block of the encoder packet that identifies the block by a sequence number that includes an internal block number and an external block number.</u><u style="single">[C17]</u><u style="single"> The method described in [C15], where each block is transmitted in a single frame.</u><u style="single">[C18]</u><u style="single"> The method described in [C15], where each block is transmitted in multiple frames.</u>