Modified connection setup for e-utra radio resource control

User equipment for a communication network, a RRC connection-setup procedure for reducing radio resource control connection setup time, a communication method for communicating data between a radio resource control (RC) and a medium access control (MCC), and signaling used in the method Radio Bearer {MODIFIED CONNECTION SETUP FOR E-UTRA RADIO RESOURCE CONTROL}

The present invention relates to a Radio Resource Control (RRC) setup procedure of E-UTRA, and more particularly, to a modified procedure for reducing RRC connection setup time.

The Third Generation Partnership Project (3GPP) uses a Universal Mobile Telecommunications System (UMTS) that supports a wide range of telecommunication applications. The UMTS architecture includes User Equipment (UE), a Core Network (CN), and UMTS Terrestrial Radio Access (UTRA) via a UTRA network (UTRAN). Recent work on improvements in UTRA includes Evolved-UTRA (E-UTRA), which forms part of what is termed the Long-Term Evolution (LTE) project. E-UTRA uses a purely packet-switched network infrastructure, without circuit-switching or dedicated connections. The air interface is OFDMA, not CDMA, on the downlink, and Single-Carrier FDMA (SC-FDMA) on the uplink. The present invention relates to E-UTRA operation. The term E-UTRA is still evolving, the respective terms E-RRC, E-MAC and E-NodeB in E-UTRA for the terms RRC, MAC and NodeB are in use but still generally accepted in this field It was not accepted. Therefore, although this specification continues to use the terms RRC, MAC and NodeB, it should be borne in mind that these terms are used in the context of UMTS E-UTRA technology.

E-UTRA, for UMTS, is expected to replace UTRA within the next 10 years. E-UTRA provides advantages over UTRA in reduced latency, higher user data rate, improved system capacity and coverage, and reduced operator cost. Given the desire for higher data rates and further allocation of 3GPP spectrum in the future, the long-term evolution of 3GPP should include broadening the transmission bandwidth beyond 5 MHz. At the same time, implementing E-UTRA within the current 5 MHz bandwidth is also advantageous.

As in UTRA, in E-UTRA, there are two interfaces, UE-UTRAN (Uu) and CN-UTRAN (Iu). The protocol in each of the Uu and Iu interfaces is a User Plane (U-Plane) protocol that governs the formatting of information for transmission, and a protocol that governs control signaling for transmission and maintains the connection between the UE and the CN. It is divided into Control Plane (C-Plane) protocols. The Uu and Iu protocols provide for the transmission of Non-Access Stratum (NAS) messages, which, in general, refer to a group of protocols used once a call-access is achieved, which It can be compared to the Access Stratum (AS) protocol group to establish. As shown in FIG. 1 , an AS involves a UE, a Radio Access Network (RAN), and a CN, whereas a NAS involves direct communication between the UE and the CN. The NAS protocol group includes Call Control (CC), Mobility Management (MM) and Session Management (SM) (as shown in FIG. 1 ). Although not shown, there is also a Short Message Services (SMS) protocol.

When the UE is powered on or when the UE moves from one cell to another, it is necessary to establish a communication path or a new communication path between the UE and the CN. When the UE is turned on, the UE continuously checks the strength of the pilot signal and transmits the information to the RNC (Radio Network Controller) of the RAN. The RNC always determines the communication path between the UE and the CN, which may entail handover of the UE to another RNC by the RNC. Once the communication path is selected, the UE needs to establish an RRC connection setup to forward data to the CN. RAB (Radio Access Bearer) is a service provided by the AS to the NAS to transmit such user data from the UE to the CN. A bearer is described as a set of parameters (attributes) that define a specific traffic aspect or a Quality-of-Service profile of a specific application or specific service, as such, a bearer is In fact, it can be considered a channel. As shown in FIG. 1 , the NAS and the AS communicate via a radio protocol that extends between the UE and the RAN. As shown in FIG. 2 , the control data is transmitted from the NAS 10 via a high-priority channel 14 or a low-priority channel 16 to RRC (Radio Resource Control). ) level 12 , and control data is typically conveyed from RRC level 12 to the MAC via at least four signaling radio bearers (SRBs) 17 to 20 . The MAC 22 then transfers this control data to a physical layer (not shown) of the UE through a transport channel, and the physical layer acts on the radio transmitting the control data to a nodeB, and controls Data is passed from NodeB to RNC. Although the uplink has been described, a similar process for transmitting control data in the downlink direction occurs at the NodeB, and Figure 2 is equally applicable to both cases.

A typical RRC level 12 typically sets up 4 SRBs in the RRC connection setup procedure to convey control data to the MAC. Each SRB is associated with a respective Radio Link Control (RLC). SRB1 is used to carry RRC signaling performed in support of AS specific needs, and RLC operates in UM (Unacknowledged mode). SRB2 is also used to convey RRC signaling performed in support of AS-specific requests, but RLC operates in Acknowledged mode (AM). SRB3 is used to convey high-priority RRC signaling (RLC in AM) performed in support of NAS-specific requests, and SRB4 is used to convey low-priority RRC signaling (RLC in AM) performed in support of NAS-specific requests. RLC). The SRB0 signaling bearer is also present, but this is not the subject of the present invention.

In one aspect, the present invention provides a communication method for communicating data between an RRC and a MAC using at least one signaling radio bearer. The communicating includes using at least one inclusive signaling radio bearer (iSRB) that serves the function of a plurality of individual signaling radio bearers (indSRBs).

It is preferable that at least two mutually-distinct priorities are defined for indSRBs, and the iSRB performs the function of indSRBs having different priorities.

The communicating step further comprises, at any one time, communicating a Protocol Discriminator (PD) as part of the iSRB to identify which of the indSRBs the iSRB is being used for. It is preferable to include It is more preferable for the PD to include binary digits in addition to those normally included in indSRB. More preferably, the PD includes an additional binary digit at one of both ends of the iSRB. More preferably, these additional binary digits comprise two binary digits.

Each indSRB preferably only relates to Acknowledged-Mode (AM) signals. More preferably, the AM signals are RRC message signals (SRB2), high-priority NAS message signals (SRB3), and low-priority NAS message signals (SRB4). Each PD identifying which of the indSRBs is being represented by an iSRB at any time is: PD=00, indSRB=SRB1 and SRB2; PD=01, indSRB=SRB3; More preferably, PD=10 and indSRB=SRB4.

The method comprises the steps of identifying each indSRB upon arrival at the MAC, prioritizing and prioritizing the indSRBs inter se only among them according to a predetermined priority schedule in the MAC. Preferably, the method further comprises transmitting the indSRBs from the MAC according to the priority given to the indSRBs.

PD is preferably not sent from MAC with indSRBs.

In a second aspect, the present invention provides an RRC connection-setup procedure for reducing a Radio Resource Control (RRC) connection setup time, the procedure comprising: a signal from a radio resource control (RRC) to a medium access control (MAC) It includes one inclusive signaling radio bearer (iSRB) communicated instead of a plurality of individual signaling radio bearers (indSRBs) for transmitting .

At least two different priorities are defined for indSRBs, and the iSRB preferably functions as indSRBs with different priorities.

The part of the iSRB communicated is preferably a protocol discriminator (PD) for identifying which at any time the iSRB is acting on behalf of which of the indSRBs. It is more preferable for the PD to include binary digits in addition to those normally included in indSRB. More preferably, the PD includes additional binary digits at one of both ends of the iSRB. It is further preferred that these additional binary digits comprise two binary digits.

Each indSRB preferably only relates to acknowledgment-mode (AM) signals. More preferably, the AM signals are RRC message signals (SRB2), high-priority NAS message signals (SRB3), and low-priority NAS message signals (SRB4). At any time, each PD identifying which of the indSRBs is represented by the iSRB is: PD=00, indSRB=SRB1 and SRB2; PD=01, indSRB=SRB3; More preferably, PD=10 and indSRB=SRB4.

In a third aspect, the present invention relates to a signaling radio bearer (SRB) used in a communication method for communicating data between an RRC and a MAC, the SRB, wherein the step of communicating data comprises: a plurality of individual signaling radio bearers ( indSRBs) using at least one inclusive signaling radio bearer (iSRB).

At least two different priorities are defined for indSRBs, and it is preferable that the iSRB performs the function of indSRBs having different priorities.

The part of the iSRB is preferably a protocol discriminator (PD) for identifying which of the indSRBs the iSRB is acting on behalf of at any time. It is more preferable for the PD to include binary digits in addition to those normally included in indSRB. More preferably, the PD includes additional binary digits at one of both ends of the iSRB. It is further preferred that these additional binary digits comprise two binary digits.

Each indSRB preferably only relates to acknowledgment-mode (AM) signals. More preferably, the AM signals are RRC message signals (SRB2), high-priority NAS message signals (SRB3), and low-priority NAS message signals (SRB4). At any time, each PD identifying which of the indSRBs is represented by the iSRB is: PD=00, indSRB=SRB1 and SRB2; PD=01, indSRB=SRB3; More preferably, PD=10 and indSRB=SRB4.

The present invention relates to reducing the time it takes to set up an RRC connection setup procedure. The four SRBs 17-20 shown in Figure 2 are set up sequentially, which has been found to typically take about 830 ms, the length of this period independent of the bit rate of the SRBs (3.7 kbps to 14.8 kbps). do. Note that the actual transmission time for the control data in these 4 SRBs does not take 830 ms, rather, it takes that time to set up the 4 SRBs and prepare to transmit them. Only a reduced number of SRBs need be set up, and if two or more conventional SRBs are transmitted using the reduced number of SRBs, the transmission setup delay can be reduced. The present invention relates to this object.

With the present invention, since there is no constraint in processing power in the network, there may be no significant gain in the overall network from the viewpoint of timing. However, at the UE, there can be significant gains in terms of processing time and simplicity.

When four SRBs are to be established, the UE checks the following about the setup of the RLC entity after receiving the RRC connection setup:

(i) check the uplink configuration for all four SRBs;

(ii) check the downlink configuration for all four SRBs;

(iii) proceed to establish 4 SRBs

When the number of SRBs is reduced to one, since the number of RLC parameters to be checked in the UE is reduced, the time and complexity required for checking (i) and (ii) will be reduced. Moreover, even if a complete RLC configuration is provided, the message size of the RRC connection setup will be significantly reduced. There is significant savings for RLC resources at both the E-Node B and the UE. Setting up just one AM RLC entity for SRB in a UE will free two AM RLC entities for the user plane that can be used for the user plane). Thus, more RABs can be supported for a given UE reference class of LTE that requires AM entities. Then, this reduces the RLC function parameters in the UE required to support a given reference class. Thus, additional support for the use of more U-plane RLC AM entities is enabled. The two main RLC functional parameters that are reduced are: (a) total RLC AM buffer size (memory); and (b) the maximum number of AM entities.

With respect to (a), the following basic criteria must always be met in construction:

<img file="KR20080098652A_D0001.tif" />

Considering the statistical multiplexing, Transmitting_window_size and Receiving_window_size are optimized for one SRB carrying NAS and RRC signaling, thereby reducing the size of the overall buffer required for the AM SRB entity.

Regarding (b), the reduction in the number of AM SRBs reduces the maximum number of RLC AM entities that need to be supported for a given UE reference class, so that there is support for more U-plane RLC AM entities. do.

1 is an overview of the C-plane and NAS protocols.

2 is a block diagram of a typical C-plane air interface protocol architecture;

Fig. 3 is a block diagram of the C-plane E-UTRAN air interface protocol architecture of the present invention, which shows the MAC priority processing of a single SRB.

4 is a block diagram illustrating interlayer signaling for RRC connection setup of an LTE system.

5 is a block diagram comparing the current REl-6 C-plane air interface protocol architecture (left) and the proposed LTE architecture (right);

6 is a block diagram illustrating MAC priority handling and Protocol Discriminator/Identifier (PD) at the transmitting side;

Preferred features of the invention are now described, by way of example only, with reference to the accompanying drawings.

The present invention is illustrated by a preferred embodiment of the RRC connection setup procedure between the UE and the E-UTRAN.

This preferred embodiment uses signal radio bearers SRB1, SRB2, SRB3 and SRB4. SRB1 operates in UM (Unacknowledged Mode), and SRB2, SRB3 and SRB4 operate in AM (Acknowledged Mode).

In the typical architecture of FIG. 2 , three AM signaling radio bearers and one UM signaling radio bearer are shown for carrying signals between RRC and MAC in E-UTRAN. Each bearer can be considered as a logical channel for carrying signals. The four SRBs 17 to 20 shown in FIG. 2 are as follows:

SRB1-UM

This SRB is used to convey RRC signaling performed in support of AS-specific requests (RLC acts as UM)

SRB2-AM

This SRB is used to convey RRC signaling performed in support of AS-specific requests (RLC acts as AM)

SRB3-AM

This SRB is used to carry high-priority RRC signaling performed in support of NAS-specific requests (RLC acts as AM)

SRB4-AM

This SRB is used to convey low-priority RRC signaling performed in support of NAS-specific requests (RLC acts as AM)

It is achievable to reduce the time of approximately 830 ms it takes to sequentially set up the four signal radio bearers SRB1 to SRB4. Since four SRBs are included in a single inclusive SRB, the delay in setting up three of the SRBs is reduced.

Typically (as well as in this preferred embodiment), the MAC 22 only accesses the data control information received on the SRBs 17-20 in a sequential rather than parallel manner. Thus, the duration of transmitting control data on four SRBs does not take longer than the duration of transmitting the data on a single SRB. However, the setup time is significantly reduced.

However, one important factor to be addressed is: MAC needs to identify signals received in one SRB and prioritize them. This is not a problem in a typical scheme with 4 SRBs, since MAC 22 has 4 input channels and knows what to expect from each. However, one incoming channel carrying four types of control data has a problem of identifying the four types, i.e. where one type of control data ends and the other type starts, and the priority only between them. presents the problem of granting to the MAC. For example, the RRC message (SRB2 message) needs to be sent by the MAC 22 before the low-priority NAS message (SRB4 message).

The present invention provides a 2-digit protocol discriminator (PD) (ie, identifier) at the left or right end of the RRC/NAS message (control data) (ie, at either end of a single SRB). )) to solve this problem. The mapping between SRB contents and PD is as follows:

<table><tgroup xmlns="http://www.oasis-open.org/tables/exchange/1.0" cols="3"><colspec colnum="1" align="justify" colname="col1" colwidth="3560" /><colspec colnum="2" align="justify" colname="col2" colwidth="3560" /><colspec colnum="3" align="justify" colname="col3" colwidth="3560" /><tbody><row><entry align="justify" colname="col1">PD</entry><entry align="justify" colname="col2">SRB mapped</entry><entry align="justify" colname="col3">Contents</entry></row><row><entry align="justify" colname="col1">00</entry><entry align="justify" colname="col2">SRB1 &amp; SRB2</entry><entry align="justify" colname="col3">RRC messages in UM mode and AM mode</entry></row><row><entry align="justify" colname="col1">01</entry><entry align="justify" colname="col2">SRB3</entry><entry align="justify" colname="col3">High-Priority NAS Messages in AM Mode</entry></row><row><entry align="justify" colname="col1">10</entry><entry align="justify" colname="col2">SRB4</entry><entry align="justify" colname="col3">Low-priority NAS messages in AM mode</entry></row></tbody></tgroup></table>

It will be appreciated that the number of digits required for a PD depends on the number of SRBs to which it is mapped.

This operation is performed in the modified RRC 30 of FIG. 3 . The modified RRC 30 differs from the RRC 12 of FIG. 2 in that it can channel the content of the conventional signaling radio bearers SRB1 , SRB2 , SRB3 and SRB4 into a single inclusive SRB 32 . .

As shown in Figure 3, the modified MAC 34 identifies three types of incoming messages delivered to a single SRB using the PD, and after identification, three queues (high-priority RRC signaling messages) place these messages in one of a first queue 36 for high-priority NAS signaling messages, a second queue 38 for high-priority NAS signaling messages and a third queue 40 for low-priority NAS signaling messages. by prioritizing these messages into a Priority Queue Distribution. 3, the PD identifier is added to the modified RRC 30, striped off in the modified MAC 34 in this embodiment, and transmitted to the physical layer of the radio transmission. It is not part of the control data. Although it should be understood that the PD identifier remains and may form part of the control data to be passed to the physical layer if necessary, once an RRC/NAS message is placed in the right queue, the PD generally serves its purpose. Satisfied (serve). After sending the RRC and NAS messages by the physical layer downstream of the MAC 34 according to the modified priority queue of the MAC 34, the received RRC and NAS messages are ASN.1 decoded by the recipient, Identifies whether each message is intended for the recipient's RRC or NAS layer. If such decoding is possible, the recipient generally does not need the PD to be sent with an RRC or NAS message.

The right side of FIG. 3 also shows that an RLC header is added to each RRC/NAS message for delivery in a single SRB, and this header is not removed in the modified MAC 34 .

Thus, the preferred embodiment can deal with setting up one AM signaling radio bearer with default configuration for L2 and L1 (using E-RLC and E-MAC entities). Along with the reduction in RRC message size, significant gains in terms of RRC connection setup time are achievable. In addition, using the default configuration reduces the complexity of checking parameters for L2 and L1 in the UE before setting up the L2/L1 entity.

4 is a diagram illustrating interlayer signaling used in the present invention. As shown, the control signal is first transmitted from E-RRC (RRC of UTRA) to E-MAC through E-RLC of UE. After establishment of the E-MAC queue, an E-RRC connection request signal is transmitted wirelessly to the E-NodeB through each L1 physical layer. In response, the E-RRC of the E-NodeB handshakes with the E-MAC of the E-NodeB, creating a connection setup with a single SRB of the present invention. Thereafter, the queue created in the E-MAC of the E-NodeB is used to control transmission of the E-RRC connection setup signal to the UE E-MAC. The UE E-MAC sends a connection setup signal to the UE E-RRC. Thereafter, one SRB of the present invention is generated by signal change between the E-RRC and the E-MAC of the UE in order to transmit a signal to the E-NodeB on which the E-RRC connection setup has been completed. The use of the present invention is indicated in FIG. 4 by a box marked "loop per SRB established".

Accordingly, the present invention proposes to reduce the number of signaling radio bearers to be set up during RRC connection setup. The motivation is C-plane standby by simplifying the RRC connection setup procedure of LTE, as disclosed in "3GPP TR 25.913, v7.1 0 (2005-09), Requirement for Evolved UTRA and Evolved UTRAN" will reduce the time

In a typical system, four signaling bearers (SRBs) are set up in the RRC connection setup procedure. These SRBs have the following functions:

SRB1 is used to convey RRC signaling performed in support of AS-specific requests (RLC operates as UM)

SRB2 is used to convey RRC signaling performed in support of AS-specific requests (RLC acts as AM)

SRB3 is used to carry high-priority RRC signaling performed in support of NAS-specific requests (RLC acts as AM)

SRB4 is used to carry low-priority RRC signaling performed in support of NAS-specific requests (RLC acts as AM)

Setting up a connection with these four SRBs and RRC is described in "Connection Setup Delay for Packet Switched Services" (Proceedings Sixth IEE International Conference on 3G and Beyond; November 2005) by C Johnson &amp; As discussed by H Holma, regardless of the bit rate (14.8-3.7 kbps) of the signaling radio bearer, about 830 ms is typically needed. If only one AM signaling radio bearer is set up during the RRC connection setup procedure as opposed to four, the reduction in delay is achievable.

To facilitate multiplexing of SRBs, a protocol discriminator/identifier (PD), also referred to as a protocol discriminator or protocol identifier, is configured with RRC signaling messages and high-priority and low-priority, as shown in Table 1. It may be added to distinguish NAS signaling (direct transmission) of rank. The PD identifies the L3 protocol to which the standard Layer-3 message belongs. The correspondence between L3 protocols and PDs is one-to-one.

<tables id="1"><table><tgroup xmlns="http://www.oasis-open.org/tables/exchange/1.0" cols="2"><colspec colnum="1" align="justify" colname="col1" colwidth="5340" /><colspec colnum="2" align="justify" colname="col2" colwidth="5340" /><tbody><row><entry align="justify" colname="col1">protocol discriminant</entry><entry align="justify" colname="col2">Mapping of SRBs</entry></row><row><entry align="justify" colname="col1">00</entry><entry align="justify" colname="col2">RRC messages (SRB1, SRB2)</entry></row><row><entry align="justify" colname="col1">01</entry><entry align="justify" colname="col2">High-Priority NAS Messages (SRB3) </entry></row><row><entry align="justify" colname="col1">10</entry><entry align="justify" colname="col2">Low-Priority NAS Messages (SRB4)</entry></row></tbody></tgroup></table></tables>

Existing SRB mapping with protocol discriminant/identifier (PD)

Although the specification allows SRB2, SRB3 and SRB4 to be configured with different RLC parameters, in practice these SRBs have the same parameters. Therefore, it can be considered that there is no special requirement to configure AM SRBs with different RLC parameters.

However, with a single SRB carrying both RRC and NAS signaling requests, handling priority at the MAC level will be further investigated.

For SRB, the default configuration parameters of L1 and L2 (E-RLC and E-MAC entities) can be used to further reduce the setup delay. Since the default configuration parameters will not be signaled to the UE by the network on an over-the-air (OTA) interface, the message size for RRC connection setup can be significantly reduced. In addition, the time and complexity required at the UE to search and check the L1 and L2 parameters for setting up the RLC and MAC, and to configure the L1 for the SRB are significantly reduced, resulting in overall gain in RRC connection setup time. there will be

Therefore, in order to achieve reduced C-plane latency in LTE, the present invention proposes to set up one AM mode signaling radio bearer with default configuration parameters of L1 and L2 (E-RLC and E-MAC entity). do. Since the proposed method eliminates the need to sequentially set up four signal radio bearers, a reduction in RRC connection setup time of about 600 ms with the proposed method is achievable. By using the default configuration with a reduction in RRC message size, additional gains are expected in terms of RRC connection setup time. Since using the default configuration will reduce the complexity in checking the parameters for L2 and L1 in the UE for correctness before setting up the L2/L1 entity of the UE which will further reduce the RRC connection setup time, This will further reduce the RRC connection setup time. The need to use UM SRB1 for E-RRC and priority handling for SRB at the MAC level needs to be further studied.

Additional references are (i) R2-051759, LTE:RAN WG2 Summary and (ii) 3GPP TR 25.813, v0.1.0 (2005-11), Radio interface protocol aspects.

Reduction of the number of signaling radio bearers to be set up during RRC connection setup has been proposed to reduce C-plane latency. However, due to reducing the number of SRBs from 4 to 1, another problem arises that the priority between RRC and NAS signaling messages is completely lost in the MAC layer of the transmitting side.

In FIG. 5 , the current RE1-6 C-plane air interface protocol architecture is shown on the left, and one proposed architecture for LTE is shown on the right. Setting up 4 SRBs in an existing UTRAN typically requires about 830 ms for the RRC connection setup procedure to complete, regardless of the bit rate of the signaling radio bearers (14.8-3.7 kbps). The reduction in delay is achievable if only one AM signaling radio bearer is set up during the RRC connection setup procedure of LTE, as shown on the right side of FIG. 5 .

To facilitate multiplexing of SRBs, a protocol identifier will be added to distinguish RRC signaling messages, high-priority and low-priority NAS signaling (direct transmission), as shown in Table 1.

A problem caused by reducing the number of SRBs to one is that the priority between RRC and NAS signaling messages is completely lost in the MAC layer of the transmitting side. In this case, the MAC layer must provide a queue on a first-come/first-serve basis, and RRC only after the RRC message is blocked and a low-priority NAS signaling message is transmitted prior to the RRC message. Such a situation arises where the message is sent.

To overcome this problem in MAC priority handling, a protocol discriminant/identifier (PD) is used, as shown in FIG. 6 . PD will only be needed on the transmit side, between RRC and MAC, for priority handling. At the MAC layer, PD is used by priority queue distribution to separate RRC/NAS signaling messages. Therefore, the PD is attached to the tail, so it can be removed before the message is placed in the appropriate queue.

The priority queue distribution entity has the task of evaluating the protocol discriminator/identifier (PD) associated with the RRC/NAS message and forwarding the RRC/NAS message to the associated priority queue.

It is important to note that the PD will not be sent over OTA, since the RRC entity at the receiving side will first do ASN1 decoding to find out whether this is an RRC message or a NAS message. Accordingly, the amount of bits transmitted via OTA is also reduced.

Accordingly, a problem caused by reducing the number of SRBs to one is that the priority between RRC and NAS signaling messages is completely lost in the MAC layer of the transmitting side. In this case, the MAC layer must provide a queue on a first-come-first-served basis, and the RRC message is blocked, and the RRC message is transmitted only after the low-priority NAS signaling message is transmitted prior to the RRC message. A simple mechanism has been described in which the priority handling of different RRC/NAS messages can be incorporated by a protocol discriminant/identifier (PD) that a MAC entity can use on the transmitting side with one SRB of LTE.

It is important to note that the PD will not be sent over OTA, since the RRC entity at the receiving side will first do ASN1 decoding to find out whether this is an RRC message or a NAS message. Accordingly, the amount of bits transmitted via OTA is also reduced.

Reduction of the number of signaling radio bearers to be set up during RRC connection setup has been proposed to reduce C-plane latency. With respect to the inter-layer signaling sequence, the E-RRC layer of the UE exits the idle mode and initiates RRC connection establishment by sending an RRC connection request message using a transparent mode on the CCCH logical channel, the message is transmitted by the MAC on the RACK transport channel.

On the E-UTRAN side, upon receiving the RRC connection request, the E-RRC layer performs admission control. E-RRC establishes the DCCH logical channel locally by configuring the parameters for layer 2 (E-RLC and E-MAC). The configured parameters are sent to the UE in the RRC Connection Request message using UM on the CCCH logical channel.

Upon receiving the RRC Connection Setup message, the E-RRC layer of the UE configures L1 and L2 using these parameters to establish a DCCH logical channel locally. When the UE establishes the RLC and MAC entities, the UE sends an RRC Connection Setup Complete message to the E-UTRAN using AM on DCCH. The exact procedure is shown in FIG. 4 .

While preferred embodiments of the present invention have been described, it will be understood that the words used herein are descriptive rather than limiting, and that changes may be made to the present invention without departing from its scope as defined by the appended claims. Each feature disclosed in this specification (including the claims) and/or shown in the drawings may be embodied in the invention independently of the other disclosed features and/or features shown.

The text of the abstract appended hereto is repeated herein as part of the specification.

A communication method for reducing radio resource control (RRC) connection setup time in E-UTRAN is one inclusive signaling radio instead of a plurality of conventional signaling radio bearers (indSRBs) to send a signal from RRC to MAC. using a bearer (iSRB). To enable the MAC to identify each idnSRB when received in the iSRB, a protocol discriminator (PD) is added to the tail (right) of each indSRB in the RRC. PD is needed because (without PD) the MAC cannot place each indSRB in the appropriate prioritizing queue for transmission to the physical layer. The PD is removed from the MAC. The preferred embodiment uses an iSRB instead of the four conventional indSRBs (SRB1, SRB2, SRB3 and SRB4), but in an alternative form, the UM SRB (SRB1) will not be present in the system and thus will not be included in the iSRB.