WO2001072057A2

WO2001072057A2 - Transport of radio network-originated control information

Info

Publication number: WO2001072057A2
Application number: PCT/SE2001/000552
Authority: WO
Inventors: Göran RUNE; Per Willars; Gert-Jan Van Lieshout
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2000-03-20
Filing date: 2001-03-16
Publication date: 2001-09-27
Also published as: WO2001072057A3; US20010036823A1; US6941132B2; US20050221849A1; AU2001242940A1

Abstract

In a radio access network (RAN) where information may be sent to a mobile radio unit using a shared radio channel shared by other mobile radio units, a first transport bearer is established between a first RAN node, e.g., a drift RNC, and a second RAN node, e.g., a base station, to transport data to be transmitted on the shared radio channel. A second transport bearer is established between the first and second RAN nodes to transport control information originated in the first RAN node that relates to the first transport bearer data. The first RAN mode then transmits the control information over the second transport bearer to the second RAN node. The control information might include, for example, scheduling information known to the first RAN node because the first RAN node supervises scheduling of data to be transmitted on the shared radio channel. The control information may provide to the mobile radio unit information needed to decode the data transmitted on the shared radio channel. Such needed information might include, for example, a frame identifier, a specific radio resource like a spreading code, and/or an indication of how different radio resources associated with different connections are multiplexed on the shared radio channel. In one example, non-limiting embodiment, the control information includes transport format indication information such as transmit format combination indicator (TFCI) information employed in third generation Universal Mobile Telephone Systems (UMTS) in accordance with the 3GPP specification.

Description

TRANSPORT OF RADIO NETWORK-ORIGINATED CONTROL INFORMATION

RELATED APPLICATIONS

This application claims priority from commonly -assigned U S

ιsιonal Patent Application Serial Nos 60/190,097 and 60/191,499, filed March 20, 2000 and March 23, 2000, respectively, the entire contents of which is incorporated herein by reference

FIELD OF THE INVENTION

The present invention relates to radio access, more specifically, to how certain control information communicated to a mobile radio terminal can be efficiently transported in a Radio Access Network (RAN)

SUMMARY OF THE INVENTION

In a radio access network (RAN) where information may be sent to a mobile radio unit using a radio channel shared by other mobile radio units, a first transport bearer is established between a first RAN node and a second RAN node to transport data ultimately to be transmitted on the shared radio channel A second transport bearer is established between the first and second RAN nodes to transport control information originated in the first RAN node that relates to the first transport bearer data The first RAN node then transmits the control information over the second transport bearer to the second RAN node

The control information might include, for example, information known to the first

RAN node because the first RAN node supervises scheduling of data to be transmitted on the shared radio channel The control information may provide the mobile radio umt with information needed to decode the data transmitted on the shared radio channel Such needed information might include a frame identifier, a specific radio resource like a spreading code m a CDMA type of communication system, and/or an indication of how different radio resources are multiplexed on the shared radio channel In one example, non-limiting embodiment, the control information includes transport format indication information such as transmit format indicator (TFI) and/or transmit format combination indicator (TFCI) information employed in third generation (3G) Universal Mobile Telephone Systems (UMTS) systems in accordance with the 3GPP specification

In a preferred, example embodiment, the first RAN node is a drift radio network controller (DRNC), and the second RAN node is a base station (BS) A third transport bearer may be established to transport dedicated radio channel data and dedicated radio channel control information through the RAN for transmission to a mobile radio unit on a dedicated radio channel This third transport bearer may be established by a serving radio network controller (SRNC) working in conjunction with the DRNC to support the connection with the mobile radio unit

In one example implementation of the present invention, a computer-generated data signal, (e g , generated in a computer in the DRNC), is transported on a separate transport bearer between the DRNC and the base station having a particular format A frame number field includes a specific frame number identifying a frame on the shared radio channel A transport format indicator field includes information relating to a particular radio channel resource in the corresponding frame In one example implementation, the transport format indicator field includes an index to a transport format table previously stored in the mobile radio unit In other words, the index addresses particular entries m the look-up table so the mobile can retrieve certain information that will allow it to receive and decode information intended for that mobile radio unit on the shared radio channel For example, since the DRNC is in charge of scheduling how data is multiplexed in a frame on the shared radio channel and allocating particular radio resources, such as channelization codes and associated spreading factors, the DRNC can convey to the mobile radio, using the transport format indicator, these types of specific details to allow the mobile radio unit to decode information sent over the shared radio channel BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features, and advantages of the invention will be apparent from the following description of the preferred but non-limiting example embodiment described in conjunction with the following drawings The drawings are not necessanh to scale or comprehensive, emphasis instead being placed upon illustrating the principles of the invention

Fig 1 is a function block diagram of a radio communications system in which the present invention may be employed,

Fig 2 is an example transport format indicator (TFI) signaling message,

Fig. 3 is an example radio access network architecture in which certain control information (like TFI and/or TFCI messages) to be commumcated to a mobile radio terminal is transported in the radio access network architecture,

Fig. 4 shows an example embodiment of the present invention in which a transport format indicator originated in a DRNC is communicated from the DRNC to a base station over a separate transport bearer,

Fig 5 is a flowchart diagram illustrating procedures in accordance with one example implementation of the present invention,

Fig 6 is an example signaling procedure for setting up a separate transport bearer between a DRNC and a base station for communicating DRNC-ongmated control information; and

Fig 7 shows an example of implementation of the invention in a differently configured RAN

DESCRIPTION OF THE FIGURES

In the following description, for purposes of explanation and not limitation, details are set forth pertaining to a specific RAN architecture, having certain interfaces, signaling, and messages, in order to provide an understanding of the present invention However, it will be apparent to one skilled in the art that the present invention may be practiced in other implementations, embodiments, and contexts that depart from these specific details

In some instances, detailed descriptions of well-known methods, interfaces, devices, and signaling techniques are omitted so as not to obscure the description of the present invention with unnecessary detail Moreover, individual function blocks are shown in some of the figures Those skilled in the art will appreciate that the functions may be implemented using individual hardware circuits, using software functioning in con_junction with a suitably programmed digital microprocessor or general purpose computer, using an application specific integrated circuit (ASIC), and/or using one or more digital signal processors (DSPs).

The architecture of an example Radio Access Network (RAN) 13, the interfaces between nodes in the RAN 13, and the physical channels on the radio interface are now described with reference to the radio communications system 10 shown in Fig. 1 User Equipment (UE) 22, such as a mobile or fixed radio terminal, is used by a subscriber to access services offered by one or more core networks (CN) 12 (only one is shown) Examples of core networks include the PSTN, the ISDN, the Internet, other mobile networks, etc Core networks may be coupled to the radio access network 13 through circuit-switched and/or packet-switched core network service nodes like Mobile Switching Center (MSC) (not shown) or a Serving GPRS Support Node (SGSN) (not shown). The radio access network 13 typically includes plural Radio Network Controllers (RNCs) 14, 16. Each RNC controls radio connectivity' with mobile terminals within a geographical area, e.g., one or more cells, by way of one or more base stations (BS) 18, 20.

For each connection between a UE mobile terminal 30 and a core network node 12, an RNC may perform one of two roles As a Serving RNC (SRNC) 18, the RNC controls the connection with the mobile terminal within the RAN Sometimes, while a connection is active, the mobile terminal moves to a geographical area controlled by another RNC This other RNC via which the connection is routed to the mobile terminal is called a Drift RNC (DRNC) 16 In the DRNC role, the RNC supports the SRNC by supplying radio resources controlled by the DRNC that are needed to support the connection with the mobile terminal The DRNC is connected to the SRNC through a logical interface labeled lur Although there is only one SRNC, there may be more than one DRNC involved m a mobile termmal-CN connection, depending on any movement of the mobile terminal and radio environment conditions

A Base Station (BS) node (18, 20), (sometimes called a "Node B"), provides UE radio connectiv in one or more cells Each cell covers a limited geographical area A base station is coupled to and controlled by a Controlling RNC (CRNC) A CRNC can be an SRNC or a DRNC The CRNC performs admission control for all the resources of the base stations it is conttolhng In addition, the CRNC performs the scheduhng of common and shared physical channels (as described below) on the radio interface for these BSs In Fig 1, the RNC 14 labeled "SRNC" is the CRNC for base station (BS1) 18 The RNC 16 labeled "DRNC" is the CRNC for base station (BS2) 20 A base station is connected to its CRNC through a logical Iub interface

User data is transported on logical "transport bearers" over the Iub/Iur interfaces between the different nodes in the RAN A transport bearer typically transports one transport channel including user data information (an information stream), and possibly also control information hke cyclic redundancy check (CRC), bit error rate (BER), transport format indicators hke TFIs and/or TFCIs (described below), etc Depending on the transport network used, these logical transport bearers may, for example, be mapped to actual ATM Adaptation Layer 2 (AAL2) transport connections (in the case of an ATM- based transport network) or User Data Protocol (UDP) transport connections (in the case of an IP-based transport network)

The radio interface may include two groups of physical radio channels (1) dedicated physical channels (referred to as DCH in the 3GPP specification) and

(2) shared physical channels (referred to as DSCH in the 3GPP specification) Dedicated physical channels may be used for transporting information between a single UE terminal and a core network and are not shared or used by other mobile terminals A shared physical channel mav be used by multiple UE terminals, e g , using a multiplexing scheme such as code or time division multiplexing One or more transport bearers are mapped to a physical radio channel

When a DRNC proΛ ides resources for a mobile terminal-core network (CN) connection, there are different DRNC control functions for dedicated types of physical channels and for shared types of physical channels For dedicated physical channels, the DRNC is involved m admission control because it must commit DRNC resources, (e g , radio resources hke spreading codes m a CDMA type system), to support the UE termmal- CN connection Once the DRNC commits some of the resources it controls to support the UE terminal-CN connection, the DRNC is not responsible for scheduhng or other supervising of the physical channel resources for that UE termmal-CN connection

Instead, this responsibility is handled by the SRNC However, the DRNC may inform the SRNC of local conditions, hke a congestion situation in a cell, and may request the SRNC to change the information rate on the dedicated physical channel

For shared physical channels, the DRNC is again involved m admission control when the mobile UE terminal-core network (CN) connection is estabhshed, to the extent its DRNC resources are needed to support that connection After the DRNC commits its resources to support the UE terminal-CN connection, however, the DRNC must perform one or more additional control or supervisory functions Because a shared physical channel is used by multiple UE terminals, the DRNC — not the SRNC — performs the final scheduhng of the resources on the shared physical channel.

In the downlink (DL) direction from RAN to the UE terminal, due to the last moment resource scheduhng in the DRNC, the UE terminal typically does not know which shared physical channel resources, will be used by the RAN for its UE termmal-CN connection at each moment m time, e g , spreading codes, frame multiplex times, etc In order to overcome this uncertainty, (1) the UE terminal may monitor continuously all shared physical channel resources to detect which resources are used for its connection, or (2) the RAN can inform the UE terminal about the common/shared resources it is using to support that UE terminal connection at each point in time For the second approach (2), the RAN must continuously inform the UE terminal about the shared physical channel resources used at each moment in time To accomplish this, the RAN must send to the UE resource identification/allocation messages on a parallel-established, dedicated radio channel before the UE is to receive the information on the shared radio channel

Radio channel information streams are transported m the RAN between the SRNC and the involved BS on transport bearers over the Iub and Iur interfaces A transport bearer transports information related to either a dedicated physical radio channel or a shared physical radio channel The information carried on a transport bearer used for transporting information related to a dedicated physical channel passes essentially transparently through the DRNC However, in diversity handover connections, the

DRNC may perform a combining (uphnk from each BS)/ splitting (downhnk to each BS) functions for this information because multiple base stations coupled to the DRNC are supporting the UE termmal-CN connection If the DRNC does not need to perform such combining/ splitting, e g , the two BSs are under the same DRNC, the DRNC need not manipulate the transported information in neither the uphnk nor downhnk direction In this case, the DRNC functions hke a conduit or relay node

For information carried on a transport bearer relating to shared physical channels, the DRNC must schedule the physical radio channel-related information received for different mobile terminals from one (or possibly more) SRNCs, l e , multiplex different information streams onto the shared radio channel at different times using different radio resources The goal is to optimize use of the shared physical channel resources on the radio interface In addition, the DRNC may perform a rate control function with the SRNC, l e , the DRNC requests the SRNC to slow down its data transmission m order to congestion on the shared physical channel

The issue is how to get this and other kinds of control information originating at the DRNC to the mobile radio so it knows when and how to decode the information sent to it on the shared radio channel Indeed, the timing of the physical channel information transport in the RAN is important for successful communication over the shared channel For scheduhng control, the information transported in the downhnk is labeled with a timestamp indicating when the information needs to be sent over the radio interface The base stations may use a receive "window" when receiving data from an SRNC or a DRNC If data is received within the window, that data can be processed and transmitted on the radio interface If the information is received too early, the base station may not have enough buffer capacity to temporarily store the received information If the information is received too late, the base station may not have enough time to process the received information and send it out on the radio interface at the correct moment time The signaling on the Iub/Iur interfaces can support procedures, (e g , a timing adjustment request message), by which the base station can request its CRNC (for shared physical channels) or an SRNC (for dedicated physical channels) to adjust the time at which information is sent to the base station

One way in which the identity of particular physical channel resources to be used, (e.g , radio resources hke spreading codes), and how these resources are to be used, (e.g., type of channel coding and coding rate), may be commumcated by the RAN to the mobile terminal is through the use of Transport Format Indication (TFI) and/or Transport Format Combination Indication (TFCI) control messages employed m the 3GPP specification The invention is not limited any specific type of transport control message format or information The TFI and TFCI are simply examples

A TFI or TFCI message may be used to describe these kinds of characteristics of a dedicated physical channel (hereafter "TFIl" or "TFCIl") as well as of a shared physical channel (hereafter "TFI2" or "TFCI2") Again, a TFI or a TFCI is just an example of a control message, and other control messages as well as other types of control information may be used. Using a TFI example for purposes of illustration only, an SRNC determines a TFIl for each dedicated transport channel, and a DRNC determines the TFI2 for each shared transport channel The base station maps the TFIl information for all dedicated transport channels (if any) to a TFCIl Similarly, the base station maps the TFI2 information for other shared transport channels (if any) to a TFCI2 If there is only one dedicated transport channel and one shared transport channel, the TFCIl corresponds to one TFIl value, and the TFCI2 corresponds to one TFI2 value Both the TFCIl and the TFCI2 are provided to the UE terminal by the BS on a dedicated physical radio channel

After receiving the TFCIl control information over the dedicated physical control channel, the UE terminal knows how the different transport channels are multiplexed onto the dedicated physical radio channel The UE is also aware of the downhnk physical channel resources, (e g , spreading factor, channelization code, etc ), that are allocated when the radio link is first set up With this information, the UE terminal can receive and demodulate information transmitted o er the dedicated radio channel

On the other hand, a shared radio channel may use one of several radio resources, (e g , one of several radio channel WCDMA spreading codes), based on the current radio resource scheduhng by the CRNC Because it is impractical for the UE terminal to know and check for information regarding all the radio resource(s) currently selected for use by the CRNC, the UE terminal is informed of the currently used radio resources for the shared physical channels, in this example, using the TFCI2 control message The TFCI2 may identify for the UE terminal the particular radio resources, (e g , spreading codes), to be used by the common/ shared physical radio channel at a certain future moment in time The TFCI2 may also indicate the time or multiplexing position within the identified frame that corresponds to the information directed to the mobile umt which should be decoded

Typically, the TFCI 1 and TFCI 2 information is an index to a look-up table provided to and stored in the mobile radio umt during the time that a connection is estabhshed between a core network and the mobile umt Information in the look-up table includes individually addressable entries of radio resource identification, e g , a channelization code and corresponding spreading factor, as well as multiplexing or timing information that identify which portions of a particular frame on the shared radio channel contain information for the particular mobile radio umt The TFCI index is used to address that look-up table and retrieve the corresponding information used by the mobile radio to then receive and properly decode information intended for it from the shared radio channel A description of TFIs and TFCIs may be found in the 3GPP RAN2 specification entided "Service Provided by the Physical Layer," 25 302, revision v 3 3 0, incorporated herein b} reference Fig 2 shows an example TFI message format in a signahng control frame An eight bit field indicates a connection frame number (CFN) followed b_} a TFI or TFCI indicator The TFI and/or TFCI may be used to address control information previously stored in a look-up table in the mobile radio as described above This reduces the amount of data to be ttansmit over the radio interface Of course, conttol information could be communicated directly rather than indirectly Optional Spare and Spare Extension bit fields are also shown.

One approach for communicating TFCI2 information is for the DRNC to insert the TFCI2 into the information stream to be transmitted on the dedicated physical radio channel The BS then transmits both the TFCIl and TFCI2 on the dedicated radio physical channel over the radio interface Fig 3 illustrates this approach The scheduled data and the TFIl conttol information to be transported on a dedicated physical traffic radio channel are received at the DRNC on a corresponding ttansport bearer See the solid hne in the transport bearer (shown as a tube) between the SRNC 14 and DRNC16 The DRNC inserts the TFCI2 into that information stream before it is forwarded to the BS via the same ttansport bearer (shown as a dashed hne in a tube) between DRNC 16 and BS2 20 This approach for conveying the TFCI2 data, however, has some drawbacks

First, insertion of the TFCI2 by the DRNC is inconsistent with a RAN architecture in which conttol and traffic information related to a dedicated physical channel are transported between SRNC and BS by "transparently" passing through the DRNC If the DRNC must insert the TFCI2, it is no longer transparent Instead, the DRNC must be knowledgeable of the data content it receives and forwards, which increases the complexity of and the delay caused by the DRNC

Second, if the TFCI2 information arrives too late at the BS, the BS will send a timing adjustment request in the uphnk direction to the RNC All uphnk information from the BS related to dedicated physical channels is supposed to be passed transparently to the SRNC Accordingly, the timing adjustment request is transparently passed from the BS by the DRNC to the SRNC However, it is the DRNC — not the SRNC — that should perform the timing adjustment function The DRNC adds the TFCI2 to the downhnk information stream to be transported OΛ er the dedicated physical radio channel

Third, insertion of the TFCI2 b) the DRNC handicaps potential changes to the RAN configuration One such change envisioned by the inventors of the present invention is described further below in conjunction with Fig 7 That change includes establishing a direct ttansport bearer between the SRNC and a BS for transporting information related to a dedicated physical channel Although such a direct ttansport bearer may have some disadvantages, (e g , combining/ splitting are not possible in the DRNC if needed), the benefits of such a solution may outweigh the drawbacks Example benefits might include a decreased load on the DRNC and a decreased ttansport delay on the dedicated physical channel in the RAN, l e , no DRNC processing and buffering delay In any event, this approach eliminates the need to include the DRNC in the ttansport bearer route for data to be transported on a dedicated physical radio channel

To overcome these drawbacks and limitations, (and perhaps others), the present invention employs a separate transport bearer between a controlhng-RNC (CRNC) and a BS to ttansport CRNC-origmated conttol information that is to be transmitted by the BS to the mobile terminal on a dedicated physical radio channel Fig 4 illustrates an example of such a separate ttansport bearer (the thick dashed hne) between a DRNC (the conttolhng RNC for BS2) and BS2 that conveys such information, e g , TFCI2 conttol information originated in the DRNC Although not shown, in a configuration that includes onh an SRNC and a base station, (l e , there is no DRNC supporting the connection), it ma\ be appropriate or otherwise desirable to establish a separate ttansport bearer to carry the control information such as TFI information generated bv the SRNC

Although the invention mav ttansmit various types of conttol information over the separate transport bearer, the non- miting, example described hereafter is TFCI2 control information Rather than inserting the TFCI2 (or other control information) into the information stream related to the dedicated physical channels, a separate ttansport bearer is estabhshed from the DRNC to the BS (the thick dashed hne) to convey the conttol information, e.g., the TFIC2.

There are three ttansport bearers estabhshed between the DRNC 16 and the base station 20. A first ttansport bearer carries to the DRNC scheduled data to be transported on a shared radio channel, Hke the DSCH. A second ttansport bearer transports the SRNC-scheduled data to be transported on a dedicated radio channel, such as the DCH, along with conttol information originated at the SRNC, such as the TFIl . The third ttansport bearer transports the conttol information originated at the DRNC 16, which in this case, is the TFCI2.

A Transport Information procedure (block 100) is now described in conjunction with the flowchart illustrated in Fig. 5. A ttansport bearer request is received at the RAN to establish a ttansport bearer between a particular UE mobile radio and a core network (block 102). A decision is made (block 104) whether the UE is in the cell under the control of the drift RNC. Of course, the connection is initially estabhshed by way of a serving RNC and a base station cell under the control of that serving RNC. However, through movement of the UE during the hfetime of the connection, it may be handed over to a cell under the conttol of a drift RNC.

If there has been no handover to a DRNC cell, the SRNC schedules user data for ttansmission over a dedicated radio channel and a shared radio channel, e.g., DCH and DSCH, respectively (block 106). The shared radio channel handles ttansmission of bursty traffic (hke WWW data) sent to UEs more efficiently than a dedicated channel. The SRNC establishes a ttansport bearer to ttansport the DCH data as well as conttol information for the DCH and possibly also the DSCH, e.g., TFIl and TFI2 (block 108). The SRNC also establishes a ttansport bearer to ttansport the DSCH data (and possibly some conttol information) (block 110).

If the UE is in a cell under the conttol of a drift RNC (DRNC), the SRNC schedules the DCH data and the DRNC schedules the DSCH data (block 112). The DRNC establishes a separate ttansport bearer between the DRNC and the base station to convey DRNC -originated control information (e g , TFCI2) (block 114) Other transport bearers are estabhshed between the DRNC and base station to transport DCH and DSCH information (block 116)

This example implementation of the present invention can be further implemented using appropriate signahng between the SRNC, DRNC, and base station (sometimes referred to as "node B") Fig 6 illustrates an example signahng diagram The SRNC communicates with the DRNC using a Radio Network Subsystem Application Protocol (RNSAP) The DRNC communicates with the base station (node B) using a Node B Application Protocol (NBAP) An ALC \P protocol is used to estabhsh ttansport bearers in the RAN

An RL_SETUP_REQUEST message is sent from the SRNC to the DRNC along with a specific request for a DCH ttansport bearer and a DSCH ttansport bearer The DRNC sends a corresponding message RL_SETUP_REQUEST to the base station node B and includes a TFIC2 transport bearer request along with the DCH and DSCH ttansport bearer requests The base station returns an RL_SETUP_RESPONSE message to the DRNC and includes DCH, DSCH, and TFCI2 ttansport bearer parameters, e g , ttansport layer addresses, binding identifiers, etc The DRNC sends an RL_SETUP_RESPONSE message to the SRNC including the DCH and DSCH ttansport bearer parameters Accordingly, DCH and DSCH transport bearers are estabhshed between the SRNC and DRNC using ALCAP signahng DCH, DSCH, and TFCI2 ttansport bearers are estabhshed between the DRNC and the base station node B also using ALCAP signahng

Fig 7 illustrates another non-hrmting, example RAN implementation where data to be transmitted on a dedicated physical radio channel is transported m the RAN directly from the SRNC to the BS, along with any associated control information, e g , the TFCIl In Fig 7, however, the direct ttansport bearer between the SRNC and the BS to ttansport dedicated physical channel information eliminates the need to relay this information through the DRNC By not routing the transport bearer through an intermediate DRNC node, internal RAN ttansport delay is decreased Thus, BS2 receives the TFIl information directly from the SRNC However, because a separate transport bearer is estabhshed between the DRNC and BS2 to carty DRNC-origmated control information relating to the DSCH data, the TFCI2 control information may also be commumcated to BS

A separate conttol information transport bearer does not need to be used in all situations If the CRNC corresponds to the SRNC, the CRNC-ongmated control information to be transmitted on a dedicated physical channel over the radio interface may be multiplexed on the direct Iub transport bearer from the SRNC to the BS along with the dedicated physical channel information A separate ttansport bearer could also be used If the CRNC is a DRNC tasked with transmitting non-scheduled data via a shared physical channel, and with generating conttol information to be transmitted on the dedicated physical channels over the radio interface, the DNRC estabhshes a separate ttansport bearer to transport DRNC-origmated control information Consequently, control information originated by the DRNC is simply sent by way of the separate transport bearer Data received from the SRNC is quickly and transparently passed through the DRNC to the base station In addition, the DRNC, and not the SRNC, is able to perform any timing adjustment functions required by the base station for data which is scheduled by the DRNC Also, the invention allows flexibility with potential changes to the RAN configuration, an example of which was just described above m conjunction with Fig 7 Namely, the dedicated channel data can go directly from the SRNC to the base station even though the shared channel scheduhng is done in the CRNC This configuration reduces delays in handhng of dedicated channel data

While the present invention has been described with respect to a particular embodiment, those skilled in the art will recognize that the present invention is not limited to the specific example embodiments described and illustrated herein Again, the invention is not limited to the TFI and/or TFCI examples provided above Different formats, embodiments, and adaptations besides those shown and described as well as many modifications, variations, and equivalent arrangements may also be used to implement the invention

Claims

WHAT IS CLAIMED IS

1 In a radio access network (RAN) (10) where information may be sent to a mobile radio umt (22) using a shared radio channel shared by other mobile radio units, a method characterized by establishing between a first RAN node and a second RAN node a first ttansport bearer to ttansport data to be transmitted on the shared radio channel, and establishing between the first RAN node and the second RAN node a second ttansport bearer to ttansport control information originated in the first RAN node relating to the first ttansport bearer data

2 The method in claim 1, further comprising the first RAN node transmitting the control information over the second ttansport bearer to the second RAN node

3 The method in claim 1, wherein the conttol information includes scheduhng information

4 The method in claim 1, wherein the conttol information indicates information needed by the mobile radio unit to decode the data transmitted over the shared radio channel

5 The method in claim 4, wherein the needed information includes one or more of the following a frame identifier, a radio channel identifier, and an indication of how different radio channels are multiplexed on the identified frame

6 The method in claim 1, wherein the conttol information includes transport format information

7 The method m claim 1, wherein the conttol information includes a ttansport format indicator

8 The method in claim 7, wherein the ttansport format indicator includes a frame identifier and an index to a lookup table stored in the mobile radio umt contaimng information relating to how a transport channel is multiplexed on the shared radio channel, wherein the shared radio channel is specified b} a channelization code and a spreading factor

9 The method in claim 1, wherein the first RAN node is a drift radio network conttoller (DRNC) (16) and the second RAN node is a base station (BS) (20)

10 The method in claim 1, wherein information may be sent to the mobile radio unit using a dedicated radio channel, the method further comprising establishing a third transport bearer to carry dedicated radio channel data and dedicated radio channel conttol information through the RAN for transmission to the mobile radio umt on the dedicated radio channel

11 The method m claim 10, wherein the dedicated radio channel carries the dedicated conttol information and the conttol information originated at the first node to the mobile radio umt

12 The method in claim 10, wherein the first RAN node is a drift radio network conttoller (DRNC) (16) and the second RAN node is a base station (BS) (20), and wherein the RAN includes a third RAN node corresponding to a serving radio network controller (SRNC) (14)coupled to the DRNC, the method further comprising the SRNC providing data to be transmitted to one or more mobile radio units to the DRNC over the third transport bearer

13 The method in claim 11, wherein the third transport bearer is estabhshed between the SRNC and the DRNC and between the DRNC and the BS

14 The method in claim 11, wherein the third ttansport bearer is estabhshed between the SRNC and the BS

15 The method in claim 1, wherein the first RAN node is a drift radio network conttoller (DRNC) (16), and the DRNC-origmated information relates to the information supervised by the DRNC 16 The method in claim 15, wherein the DRNC-origmated information is a traffic format indication message originated by the DRNC

17 The method in claim 16, wherein the traffic format indication message originated by the DRNC instructs the mobile radio unit how to receive information on the shared radio channel

18 A computer-generated data signal embodied in an electrical signal transported on a radio access network (RAN) ttansport bearer estabhshed between a first RAN node corresponding to a drift radio network conttoller (16) and a second RAN node corresponding to a base station (20), comprising a frame number field including a specific frame number corresponding to a frame on a radio channel, and a transport format field including information relating to a particular radio channel resource useable by a mobile radio umt to receive information directed to the mobile radio umt

19 The computer-generated data signal in claim 18, wherein the ttansport format field includes information that may be used to address a ttansport format table stored in a mobile radio unit (22)

20 The computer-generated data signal in claim 18, wherein the ttansport format field contains information that may be used by a mobile radio umt to receive information intended for the mobile radio umt carried on a shared radio channel

21 The computer-generated data signal in claim 18, wherein the ttansport format field includes a transport format combination indicator (TFCI) generated by the drift radio network conttoller

22 In a radio access network (RAN) (10) where information may be sent to one or more mobile radio umts (22) using a shared radio channel, a RAN node for communicating with a base station (20), comprising a controller (16) configured to estabhsh a first ttansport bearer to the base station to ttanspoit data to be transmitted on the shared radio channel, and to estabhsh a second transport bearer to the base station to transport conttol information originated m the RAN node

23 The RAN node in claim 22, wherein the control information indicates to a mobile radio unit receiving transmissions from the base station information needed to decode information ttansmitted over the shared radio channel

24 The RAN node m claim 23, wherein the needed information includes one or more of the following a frame identifier, a radio channel identifier, and an indication of how different radio channels are multiplexed on the identified frame

25 The RAN node in claim 22, wherein the conttol information includes ttansport format information.

26 The RAN node in claim 25, wherein the control information includes a ttansport format indicator

27 The RAN node in claim 26, wherein the transport format indicator includes a frame identifier and information that is useable by a mobile radio to address a lookup table stored in the mobile radio contaimng information relating to how a radio channel is multiplexed in the identified frame, wherein the radio channel is specified by a channelization code and a spreading factor

28 The RAN node in claim 22, wherein the first RAN node is a drift radio network conttoller (DRNC) (16) configured to communicate with a serving RNC

(SRNC) (14)

29 The RAN node in claim 28, wherein the conttoller is configured to estabhsh a third ttansport bearer to the base station to transmit data be ttansmitted on a dedicated radio channel 30 The RAN node in claim 22 in conjunction with the radio access network, wherein the RAN further comprises a serving radio network conttoller (SRNC) (14) for initially establishing a connection with a mobile radio umt over a radio interface, where the first RAN node is a drift radio network controller (DRNC) (16) for providing resources to the SRNC to support the connection, wherein the DRNC is configured to estabhsh the first ttansport bearer to ttansport the connection information from the DRNC to the base station on the shared radio channel and the second transport bearer to ttansport conttol information related to the connection information from DRNC to the base station

31 The radio access network in claim 30, wherein the SRNC is configured to estabhsh a third transport bearer to carry connection information to be ttansmitted on a dedicated radio channel between the base station and the mobile radio umt

32 The radio access network in claim 31, wherein the SRNC is configured to estabhsh the third ttansport bearer with the base station

33 The radio access network m claim 31, wherein the SRNC is configured to estabhsh the third ttansport bearer with the base station by way of the DRNC