JP5507753B2 - Radio bearer management at donor base stations in wireless networks with relays - Google Patents

Description

Priority claim

  This patent application is assigned to the assignee of this patent application and is expressly incorporated herein by reference and filed on Mar. 25, 2010 for “Long Term Evolution System with Relay. US Provisional Patent Application No. 61 / 317,632 entitled Method and Apparatus that Facilitates Bearer Management at an Evolved Node B For Long Term Evolution Systems with Relays. Insist on the interests of.

  Certain aspects of the present disclosure generally relate to wireless communication systems, and more particularly to techniques for managing radio bearers in a telecommunications network with relays.

  Wireless communication systems have been widely developed to provide various types of content such as voice, data, and the like. These systems can be multiple access systems that can support communication with multiple users by sharing available system resources (eg, bandwidth, transmit power, etc.). Examples of such multiple access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP long term evolution (LTE) systems, and Includes orthogonal frequency division multiple access (OFDMA) systems and the like.

  In general, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals. Each terminal communicates with one or more base stations via transmissions on forward and reverse links. The forward link (ie, downlink) refers to the communication link from the base stations to the terminals, and the reverse link (ie, uplink) refers to the communication link from the terminals to the base stations. This communication link may be established by a single input single output system, a multiple input single output system, a multiple input multiple output (MIMO) system, or the like.

A MIMO system applies multiple (N _T ) transmit antennas and multiple (N _R ) receive antennas for data transmission. The MIMO channel formed by N _T transmit antennas and N _R receive antennas is divided into N _S independent channels, also referred to as spatial channels. Here, N _S ≦ min {N _T , N _R }. Each of the N _S independent channels corresponds to a dimension. A MIMO system can provide improved performance (eg, higher throughput and / or higher reliability) if additional dimensions generated by multiple transmit and receive antennas are utilized. .

  MIMO systems support time division duplex (TDD) and frequency division duplex (FDD) systems. In a TDD system, the forward link transmission and the reverse link transmission are in the same frequency domain so that the reciprocal principle allows the forward link channel to be estimated from the reverse link channel. This allows the access point to extract transmit beamforming gain on the forward link when multiple antennas are available at the access point.

  A wireless communication system may comprise a donor base station that communicates with wireless terminals via a relay base station. A relay base station may communicate with a donor base station via a backhaul link and communicate with a terminal via an access link. In other words, the relay base station may receive downlink messages from the donor base station via the backhaul link and relay these messages to the terminal via the access link. Similarly, the relay base station may receive uplink messages from the terminal via the access link and relay these messages to the donor base station via the backhaul link. Therefore, the relay base station supplements the effective communication range area and supports filling the “effective communication range hall”.

  In general, a bearer is defined as a packet flow with a quality of service (QoS) defined between the gateway and user equipment (UE). In a telecommunications network with a relay node, the bearer applied for the packet flow between the relay node and the served UE (referred to as “Uu bearer”) is the relay node. And a data radio bearer (DRB) applied for relay packet flow between the associated donor base station (DeNB) (referred to as “Un data radio bearer”) Is done. In some cases, if the conditions of the backhaul link between the relay node and the DeNB deteriorate, or if too many Uu bearers are allowed over the backhaul link, the DeNB may Can be congested at the Un interface serving the. Meanwhile, the Uu interface between the relay node and the relay served UE does not observe any capacity issues. Thus, there is a need for techniques and mechanisms for managing radio bearers transmitted by donor base stations and relay nodes in wireless networks.

  Certain aspects of the present disclosure provide a method for operating a donor base station having a first plurality of radio bearers (RBs) that interface with a relay node. The method generally includes determining traffic congestion in a first plurality of RBs and at least one of a second plurality of RBs interfacing between a relay node and at least one user equipment (UE). Taking one or more actions to trigger one removal.

  Certain aspects of the present disclosure also provide a donor base station having a first plurality of radio bearers (RBs) that interface with relay nodes. The donor base station generally includes a traffic monitor component configured to determine traffic congestion in the first plurality of RBs. The donor base station further takes one or more actions to trigger removal of at least one of the second plurality of RBs that interface between the relay node and at least one user equipment (UE). The radio bearer manager component is configured.

  Certain aspects of the present disclosure provide an apparatus for wireless communication having a first plurality of radio bearers (RBs) that interface with relay nodes. The apparatus generally includes at least one of a means for determining traffic congestion in the first plurality of RBs and a second plurality of RBs that interface between the relay node and the at least one user equipment (UE). Taking one or more actions to trigger removal.

  Certain aspects of the present disclosure comprise a computer-readable medium having stored instructions for operating a donor base station having a first plurality of radio bearers (RBs) that interface with a relay node. Provide computer program products. These instructions generally determine traffic congestion in the first plurality of RBs and remove at least one of the second plurality of RBs that interface between the relay node and the at least one user equipment (UE). Can be performed by one or more processors to take one or more actions to trigger.

The foregoing specific description, briefly summarized, in a manner in which the above-described features of the present disclosure are understood in more detail, is made by reference to aspects. Some of them are illustrated in the accompanying drawings. However, since this description is compatible with other equally valid aspects, the accompanying drawings show only certain exemplary aspects of the present disclosure and may not be considered as limiting the scope thereof. It should be noted.
FIG. 1 illustrates a multiple access wireless communication system. FIG. 2 is a block diagram of the communication system. FIG. 3 illustrates an exemplary wireless communication system with a relay base station in accordance with certain aspects of the present disclosure. FIG. 4 is a block diagram of a wireless communication system with relay nodes in accordance with certain aspects of the present disclosure. FIG. 5 illustrates an exemplary communication device that manages radio bearers in accordance with certain aspects of the subject disclosure. FIG. 6 illustrates an example of mapping between radio bearers in a wireless communication system in accordance with certain aspects of the present disclosure. FIG. 7 illustrates examples of operations that may be performed by a communication device in accordance with certain aspects of the present disclosure. FIG. 8 is a sequence diagram illustrating an example of an operation for an indirect Uu bearer deactivation mechanism in accordance with certain aspects of the present disclosure. FIG. 9 is a sequence diagram illustrating an example operation for a direct Uu bearer deactivation mechanism in accordance with certain aspects of the present disclosure. FIG. 10 is a sequence diagram illustrating an example operation for a user equipment context release mechanism in accordance with certain aspects of the present disclosure.

  Certain aspects of the present disclosure provide apparatus and techniques for managing radio bearers in a wireless communication network having relay nodes and donor base stations. For example, in some networks, such as an LTE network with relay nodes, a relay node may serve multiple UE packet flows. The Uu radio bearer used for the UE packet flow between the relay node and the UE served thereby is for the relay packet flow between the relay and its donor base station. Is transmitted by the Un data radio bearer used for

  As mentioned above, if the backhaul link condition between the relay node and the donor base station deteriorates, or if too many UE flows are allowed over the backhaul link, the donor base station Can experience congestion at its Un interface. When this happens, it is desirable for the donor base station to release a UE context or several Uu bearers for the UE being served under the relay node. However, the donor base station can see the Uu bearer under the LTE relay architecture, but does not directly manage the control plane transaction of the Uu interface. This therefore allows relay nodes and donor base stations to efficiently manage radio resources in order to provide UE flows with Un radio bearers while maintaining a constant quality of service across the communication network. Indicates a challenge.

  According to an aspect, a mechanism for an LTE relay network is provided for a donor base station to remove a Uu bearer transmitted by a donor base station Un bearer when the Un bearer is congested. The Certain aspects of the present disclosure generally provide a mechanism for performing an indirect release of a Uu bearer, a direct release of a Uu bearer, or a UE context release for a given UE. It is noted that the Uu bearer refers to the radio bearer at the interface between the relay node and the user equipment (UE) and may also be referred to as the Uu radio bearer or the Uu data radio bearer. Furthermore, the Un bearer generally refers to the bearer of the interface between the relay node and the associated donor base station, and may also be referred to as the Un radio bearer or Un data radio bearer.

  The techniques described herein include, for example, code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal frequency division multiple access (OFDMA) networks, single It can be used for various wireless communication networks such as carrier FDMA (SC-FDMA) networks and the like. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes wideband CDMA (W-CDMA) and low chip rate (LCR). cdma2000 covers IS-2000, IS-95, and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA network may implement radio technologies such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, Flash-OFDM®, and the like. UTRA, E-UTRA, and GSM are part of the Universal Mobile Telecommunication System (UMTS). Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). These various radio technologies and standards are known in the art. For clarity, certain aspects of these techniques are described below for LTE, and LTE terminology is used in much of the description below.

  Single carrier frequency division multiple access (SC-FDMA) is a technique that utilizes single carrier modulation and frequency domain equalization. SC-FDMA has the same performance and substantially the same overall complexity as an OFDMA system. SC-FDMA signals have a low peak-to-average power ratio (PAPR) due to their inherent single carrier structure. SC-FDMA has drawn particular attention in uplink communications where low PAPR is greatly beneficial to mobile terminals in terms of transmit power efficiency. This is currently the operating premise for the uplink multiple access scheme in 3GPP Long Term Evolution (LTE) or Evolved UTRA.

  As illustrated in FIG. 1, a multiple access wireless communication system according to one embodiment is illustrated. The access point 100 (AP) includes a plurality of antenna groups, one including 104,106, the other including 108,110, and the other including 112,114. In FIG. 1, only two antennas are shown for each antenna group. However, more or fewer antennas may be utilized for each antenna group. Access terminal 116 (AT) is in communication with antennas 112, 114 that transmit information to access terminal 116 on forward link 120 and receive information from access terminal 116 on reverse link 118. . Access terminal 122 is in communication with antennas 106, 108 that transmit information to access terminal 122 on forward link 126 and receive information from access terminal 122 on reverse link 124. In an FDD system, the communication links 118, 120, 124, 126 may use different frequencies for communication. For example, forward link 120 may use a different frequency than that used by reverse link 118.

  Each group of areas and / or antennas designed to communicate is often referred to as an access point sector. In an embodiment, each antenna group is designed to communicate with access terminals in a sector of the area covered by access point 100.

  For communication on the forward links 120, 126, the transmit antenna at the access point 100 utilizes beamforming to improve the signal-to-noise ratio of the forward link of another access terminal 116, 124. Furthermore, access points that use beamforming to transmit to access terminals that are randomly scattered over the coverage area are more accessible in neighboring cells than access points that transmit to a single antenna to all access terminals. Less interference to the terminal.

  According to certain aspects, the AT 116 may communicate with the AP 100 via a radio interface having a Uu radio bearer. Further, additional APs 100 can be connected to each other by an interface known as X2 and to a network node, such as an enhanced packet core (EPC) node, by an S1 interface.

  An access point can be a fixed station used to communicate with a terminal and is referred to as an access point, Node B, Evolved Node B (eNB), eNode B, or some other terminology. The An access terminal may also be called an access terminal, user equipment (UE), a wireless communication device, a wireless terminal, an access terminal, or some other terminology.

  FIG. 2 is a block diagram of an embodiment of a transmitter system 210 (also known as an access point) and a receiver system 250 (also known as an access terminal) in a MIMO system 200. In transmitter system 210, traffic data for a number of data streams is provided from a data source 212 to a transmit (TX) data processor 214.

  In an embodiment, each data stream is transmitted via a respective transmit antenna. TX data processor 214 formats the traffic data for each data stream, encodes and interleaves based on the particular encoding scheme selected for this data stream, and encodes the encoded data. I will provide a.

  The coded data for each data stream can be multiplexed with pilot data using OFDM techniques. The pilot data is typically a known data pattern that is processed in a known manner and can be used at the receiver system to estimate the channel response. The multiplexed pilot and encoded data for each data stream is sent to the specific modulation scheme selected for the data stream (eg, BPSK, QPSK, M-PSK, or M-QAM, etc.). Based on the modulation (eg, symbol map), modulation symbols are provided. The data rate, coding, and modulation for each data stream can be determined by instructions executed by processor 230.

The modulation symbols for all data streams are provided to a TX MIMO processor 220 that processes the modulation symbols (eg, for OFDM). TX MIMO processor 220 then provides N _T modulation symbol streams to N _T transmitters (TMTR) 222a through 222t. In one embodiment, TX MIMO processor 220 applies beamforming weights to the symbols of the data stream and the antenna from which the symbols are transmitted.

Each transmitter 222 receives and processes a respective symbol stream to provide one or more analog signals, and further provides a modulation signal suitable for transmission over a MIMO channel. The analog signal is adjusted (eg, amplified, filtered, and upconverted). _{N T} modulated signals from transmitters 222a through 222t are then transmitted from _{N T} antennas 224a through 224t.

At receiver system 250, the modulated signals transmitted are received by _{N R} antennas 252a through 252r, the received signal from each antenna 252 is provided to a respective receiver (RCVR) 254a through 254r. Each receiver 254 adjusts (eg, filters, amplifies, and downconverts) each received signal, digitizes the adjusted signal to provide a sample, further processes the sample, and responds. To provide a “received” symbol stream.

RX data processor 260 then receives the N _R symbol streams from N _R receivers 254, received these symbol streams, and processing based on a particular receiver processing technique, Provide _NT “detected” symbol streams. RX data processor 260 then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for this data stream. The processing by RX data processor 260 is complementary to that performed by TX MIMO processor 220 and TX data processor 214 at transmitter system 210.

  The reverse link message may comprise various types of information regarding the communication link and / or the received data stream. The reverse link message is then processed by a TX data processor 238 that receives traffic data for a number of data streams from a data source 236, modulated by a modulator 280, coordinated by transmitters 254a-254r, and Sent back to station 210.

  In transmitter system 210, the modulated signal from receiver system 250 is received by antenna 224, conditioned by receiver 222, demodulated by demodulator 240, processed by RX data processor 242, and received by receiver system 250. Extract the reverse link message sent by. Further, processor 230 determines which precoding matrix to use to determine the beamforming weights and processes this extracted message.

  According to certain aspects of the present disclosure, transmitter system 210 includes additional components for operating in a wireless communication network having a relay node as described herein. Specifically, the transmitter system 210 can be configured as a donor base station as shown in FIGS. 4-5. According to certain aspects, transmitter system 210 may be configured to perform traffic monitoring operations and Uu bearer management operations as described below.

  According to certain aspects, logical channels are classified into control channels and traffic channels. The logical control channel comprises: Broadcast control channel (BCCH), which is a DL channel for broadcasting system control information. Paging control channel (PCCH), which is a DL channel that transfers paging information. A multicast control channel (MCCH), which is a point-to-multipoint DL channel used to transmit multimedia broadcast and multicast service (MBMS) schedule and control information for one or several MTCHs. Generally, after establishing an RRC connection, this channel is only used by UEs that receive MBMS (Note: old MCCH + MSCH). Dedicated Control Channel (DCCH) is a point-to-point bi-directional channel that transmits dedicated control information and is used by UEs having an RRC connection. In an aspect, the logical traffic channel comprises a dedicated traffic channel (DTCH), which is a point-to-point bi-directional channel dedicated to one UE for the transfer of user information. A multicast traffic channel (MTCH) is a point-to-multipoint DL channel for transmitting traffic data.

  According to an aspect, the transmission channel is classified into DL and UL. The DL transmission channel comprises a broadcast channel (BCH), a downlink shared data channel (DL-SDCH), and a paging channel (PCH). The PCH supports UE power saving by being broadcast throughout the cell and mapped to PHY resources used for other control / traffic channels (eg, DRX cycle is indicated to the UE by the network) Etc.). The UL transmission channel comprises a random access channel (RACH), a request channel (REQCH), an uplink shared data channel (UL-SDCH), and a plurality of PHY channels. The PHY channel comprises a set of DL channels and UL channels.

The DL PHY channel comprises:
Common pilot channel (CPICH)
Synchronization channel (SCH)
Common control channel (CCCH)
Shared DL control channel (SDCCH)
Multicast control channel (MCCH)
Shared UL allocation channel (SUACH)
Acknowledgment channel (ACKCH)
DL physical shared data channel (DL-PSDCH)
UL power control channel (UPCCH)
Paging indicator channel (PICH)
Load indicator channel (LICH)
The UL PHY channel comprises:
Physical random access channel (PRACH)
Channel quality indicator channel (CQICH)
Acknowledgment channel (ACKCH)
Antenna subset indicator channel (ASICH)
Shared request channel (SREQCH)
UL physical shared data channel (UL-PSDCH)
Broadcast pilot channel (BPICH)
For the purposes of this document, the following abbreviations apply:
ACK acknowledgment
AM Acknowledge mode
AMD Acknowledgment mode data
ARQ automatic repeat request
BCCH broadcast control channel
BCH broadcast channel
BW bandwidth
C-Control-
CB contention base
CCE control channel element
CCCH common control channel
CCH control channel
CCTrCH coded composite transmission channel
CDM code division multiplexing
CF contention free
CP cyclic prefix
CQI channel quality indicator
CRC cyclic redundancy check
CRS common reference signal
CTCH common traffic channel
DCCH dedicated control channel
DCH dedicated channel
DCI downlink control information
DL downlink
DRS dedicated reference signal
DSCH downlink shared channel
DSP digital signal processor
DTCH dedicated traffic channel
E-CID Enhanced cell identification information
EPS Evolved Packet System
FACH Forward link access channel
FDD frequency division duplex
FDM frequency division multiplexing
FSTD Frequency switching transmission diversity
HARQ hybrid automatic iteration / request
HW hardware
IC interference cancellation
L1 Layer 1 (physical layer)
L2 layer 2 (data link layer)
L3 layer 3 (network layer)
LI length indicator
LLR log likelihood ratio
LSB least significant bit
MAC medium access control
MBMS Multimedia Broadcast Multicast Service
MCCH MBMS point-to-multipoint control channel
MMSE Minimum mean square error
MRW motion reception window
MSB most significant bit
MSCH MBMS point-to-multipoint scheduling channel
MTCH MBMS point-to-multipoint traffic channel
NACK non-acknowledgment
PA power amplifier
PBCH physical broadcast channel
PCCH paging control channel
PCH paging channel
PCI physical cell identifier
PDCCH Physical downlink control channel
PDU protocol data unit
PHICH Physical HARQ indicator channel
PHY physical layer
PhyCH physical channel
PMI precoding matrix indicator
PRACH physical random access channel
PSS primary synchronization signal
PUCCH Physical uplink control channel
PUSCH Physical uplink shared channel
QoS quality of service
RACH random access channel
RB resource block
RLC radio link control
RRC radio resource control
RE resource element
RI rank indicator
RNTI radio network temporary identifier
RS reference signal
RTT round trip time
Rx reception
SAP service access point
SDU service data unit
SFBC spatial frequency block code
SHCCH Shared channel control channel
SINR Signal-to-interference and noise ratio
SN sequence number
SR scheduling request
SRS sounding reference signal
SSS secondary synchronization signal
SU-MIMO Single user multiple input multiple output
SUFI super field
SW software
TA timing advance
TCH traffic channel
TDD time division duplex
TDM time division multiplexing
TFI transmission format indicator
TPC transmission power control
TTI transmission time interval
Tx transmission
U-User-
UE user equipment
UL uplink
UM non-acknowledge mode
UMD unacknowledged mode data
UMTS Universal Mobile Communication System
UTRA UMTS Terrestrial Radio Access
UTRAN UMTS Terrestrial Radio Access Network
VOIP Voice over Internet Protocol
MBSFN Multicast / Broadcast Single Frequency Network
MCH multicast channel
DL-SCH downlink shared channel
PDCCH Physical downlink control channel
PDSCH physical downlink shared channel (typical relay system)
FIG. 3 illustrates an example wireless communication system 300 in which certain embodiments of the present disclosure can be implemented. As illustrated, system 300 communicates with user equipment (UE) 304 via a relay BS 306 (also known as a relay access point or relay node) (donor access point, donor base). A donor base station 302 (also known as a station, donor eNodeB, or DeNB). Relay BS 306 may communicate with donor BS 302 via backhaul link 308 and with UE 304 via access link 310.

  In other words, relay BS 306 may receive downlink messages from donor BS 302 via backhaul link 308 and relay these messages to UE 304 via access link 310. Similarly, relay BS 306 may receive uplink messages from UE 304 via access link 310 and relay these messages to donor BS 302 via backhaul link 308. Therefore, the relay BS 306 supplements the effective communication range area and assists in filling the “effective communication range hole”.

  According to an aspect, the relay BS 306 can communicate with the UE 304 using at least one Uu radio bearer configured for the access link 310 (ie, relay a downlink message to the UE, Receive uplink messages). According to an aspect, the relay BS 306 can communicate with the donor BS 302 utilizing at least one Un radio bearer configured for the backhaul link 308.

  FIG. 4 illustrates a block diagram of an example system 400 configured to perform techniques for managing and mapping radio bearers in accordance with certain aspects of the present disclosure. The example system 400 represents a wireless telecommunications network having multiple UEs 410, relay nodes 420, base stations 430, 435, and network nodes 440.

  Base station 430 operates as a donor base station for relay node 420. Thus, the relay node 420 can serve many UEs 410 by relaying radio communication between the UE 410 and the base station 430. Base station 430 provides communication between a plurality of UEs 410 and at least one network node 440. Network node 440 is configured to manage network services for UE 410. According to certain aspects, the network node 440 may include an evolved packet such as a mobility management entity (MME), a packet data network (PDN) gateway (P-GW), or a service providing gateway (S-GW). Can be a core (EPC) network node. According to an aspect, the S1 interface connects the base station 430 and the network node 440. In general, the network node 440 controls bearer and connection management by control plane signals transmitted over the S1 interface. Further, base station 430 can be interconnected to base station 435 to share load, interference, or handover related information.

  According to certain aspects, many Uu radio bearers are utilized to transmit data packet flows between the relay node 420 and the UE 410. Similarly, many Un radio bearers are utilized to carry flows between the relay node 420 and the base station 430, and many to route traffic from the network node 440 to the UE 410. Uu EPS bearers are used. The Uu radio bearer of UE 410 is transmitted by the Un bearer of relay node 420. As described above, the base station 430 can see both Un bearers and Uu bearers, and the base station 430 can also be used in both the Un bearer and the Uu bearer in some aspects of queue management and bearer mapping. Can work. However, in the conventional configuration, the base station 430 cannot directly initiate a control plane transaction for the Uu bearer transmitted by the Un bearer. However, if the Un interface is congested, the base station 430 may need to release not only some Uu bearers, but also UE content being transmitted by these Un bearers. According to an aspect, as described further below, when the Un interface is congested, the base station 430 performs an operation that will remove at least one Uu bearer transmitted by the Un interface. Configured as follows. In accordance with certain aspects, in accordance with a mechanism for facilitating Uu bearer removal described herein, UE 410, relay node 420, base stations 430, 435, and network node 440 can manage Uu bearer management. Configured to adjust.

  FIG. 5 illustrates a donor base station 500 for wireless communication in accordance with certain aspects of the present disclosure. Certain aspects of the present disclosure are described in terms of donor base station 500, including, for example, a macro cell, femto cell, pico cell base station, access point, relay node, mobile base station, one of these. It is understood that other suitable communication devices, such as substantially any wireless device that transmits signals to one or more other devices in a wireless network, and / or to a wireless network, are contemplated. According to an aspect, the donor base station 500 can be a donor base station 430 as described in FIG.

  According to an aspect, the donor base station 500 generally includes a traffic monitor component 502, a bearer manager component 504, and a relay node serving and PDN gateway (S / P-GW) component 506. Including. The traffic monitor component 502 is configured to monitor traffic via an interface connected to the donor base station 500 and detect traffic congestion conditions at a given interface. According to an aspect, the traffic monitor component 502 can determine traffic congestion at a Un interface configured to interface between the donor base station 500 and a relay node. According to an aspect, the relay node S / P-GW component 506 is configured with functions, such as S-GW- and P-GW-, for example session establishment, for connected relay nodes. , Configured to provide EPS bearer management for relay nodes.

  In general, bearer manager component 504 is configured to perform bearer management operations as described herein. For example, the bearer manager component 504 may manage the Un interface between the donor base station 500 and the connected relay node to transmit Uu bearers and other data flows. Bearer manager component 504 may also establish an S1 interface between a network node such as a mobility management entity and donor base station 500 for signaling and network coordination.

  According to an aspect, bearer manager component 504 includes a selection component 508 and a command component 510. The selection component 508 selects at least one of a plurality of Uu radio bearers to deactivate from the Un interface of the donor base station 500 to mitigate traffic congestion at the Un interface. Can be configured. According to an aspect, the selection component 508 can determine a Uu radio bearer to be deactivated based on Uu bearer assignment and retention priority (ARP).

  The command component 510 is configured to generate a signal to a network node, such as a mobility management entity. This removes at least one of the Uu bearers at the Un interface. According to an aspect, the command component 510 can generate an update bearer request command to modify the QoS of the Un interface. This removes at least one Uu bearer at the Un interface. According to an aspect, the command component 510 can generate a bearer release indication command to directly deactivate at least one Uu bearer transmitted on the Un interface of the donor base station 500. . According to an aspect, the command component may generate a radio terminal context release request command requesting release of the UE context stored by the donor base station 500 and the connected network node.

  FIG. 6 illustrates an example mapping 600 between Uu radio bearers 602 and Un radio bearers 604 in an example wireless communication system 400, as described above, in accordance with certain aspects of the present disclosure. A plurality of Uu radio bearers 602 provide data flow between the wireless terminal 410 and the relay node 420. Multiple Uu radio bearers 602 are mapped to a single Un radio bearer 604 at the interface 606 between the relay node 420 and the donor base station 430. The mapped Uu radio bearer 602 shows the data packet flow from the wireless terminal 410 to the S / P-GW 440 of the wireless terminal in the Uu Evolved Packet System (EPS) bearer. According to an aspect, the donor base station 430 can be the donor base station 500 shown in FIG.

  As described above, certain aspects of the present disclosure provide a mechanism for mapping Uu bearers carried on the Un interface 606 when traffic congestion is detected on the Un interface 606. According to an aspect, donor base station 430 may take one or more actions to initiate removal of at least one of Un radio bearers 602 mapped from Un interface 606 to Un radio bearers 604. Can be configured.

  FIG. 7 illustrates an example of an operation 700 for operating a donor base station in accordance with certain aspects of the present disclosure. According to an aspect, an example of operation 700 can be performed by a donor base station having a first plurality of radio bearers that interface with a relay node. For example, donor base station 500 shown in FIG. 5 can be configured to perform operation 700. It is contemplated that other suitable components and devices configured in accordance with certain aspects of the present disclosure may be utilized to perform the example operation 700.

  Operation 700 begins at 702 by determining traffic congestion of the first plurality of radio bearers. According to an aspect, the donor base station can monitor traffic on the first plurality of radio bearers to detect congestion on at least one of the first plurality of radio bearers.

  At 704, the donor base station can detect at least one of the second plurality of radio bearers that interface between the relay node and the at least one user equipment (UE) in response to detecting traffic congestion. Take one or more actions to trigger removal. The action or actions taken directly or indirectly cause removal of at least one of the second plurality of radio bearers by any number of intermediate steps, procedures, processes, or chain of events. It is understood. For example, in an LTE network having multiple network components that coordinate to support wireless communication, one or more actions taken by a donor base station may be subsequently performed between network components in response to the one or more actions. Can trigger other messaging. According to an aspect, the one or more actions taken by the donor base station include an action for indirect Uu bearer deactivation by the donor base station, and a donor base station, as further described below. May include an operation for direct Uu bearer deactivation by the UE and an operation for UE context release by the donor base station. As noted, the operations performed by the donor base station described below are network configurations that result in any number of subsequent requests, responses, reconfigurations, acknowledgments, indications, commands, and Uu bearer removal. It is understood that signaling between elements can be triggered.

  FIG. 8 is a sequence diagram illustrating operations for an indirect Uu bearer deactivation mechanism in accordance with certain aspects of the present disclosure. For clarity, these operations are shown as being performed by the example system 400 shown in FIG. However, it is understood that these example operations may be performed by any suitable apparatus and components in accordance with aspects of the present disclosure.

  At 802, the donor base station detects traffic congestion in the Un bearer. At 804, the donor base station initiates Un bearer reduction by modifying the QoS of the congested Un bearer. In general, the QoS of a bearer can be defined by a number of parameters. According to certain aspects, the QoS parameters are scalars used as a reference for bearer level packet forward processing (eg, scheduling weight, admission threshold, queue management threshold, link layer protocol settings, etc.). QoS class identifier (QCI), and the assignment and retention priority (ARP) used to determine whether bearer establishment or modification requests need to be rejected or can be accepted in case of resource limitations A guaranteed bit rate (GBR) indicating a bit rate that can be expected to be provided by a guaranteed bit rate (GBR) radio bearer, and a bit rate that can be expected to be provided by a GBR radio bearer. And a maximum bit rate (MBR) indicating a limit to the rate. According to an aspect, the donor base station may modify at least one of the QoS parameters of the congested Un bearer to reduce the indicated QoS. As an example, the donor base station may reduce the GBR of the Un bearer from 10 Mbps to 8 Mbps.

  According to an aspect, as shown in FIG. 8, the relay node serving / packet gateway component in the donor base station generates an “update bearer request” to the relay node's MME. Un bearer reduction can begin. As shown, the relay node's MME may respond with a modify bearer request and a session management request to control the system's Un bearer configuration.

  As a result, the relay node then recognizes at 806 that the updated QoS of the Un bearer does not support the Uu bearer transmitted by this Un bearer. According to an aspect, after Un bearer modification is initiated by the network, the relay node detects insufficient Un bearer QoS. As shown, the relay node receives a radio resource controller connection reconfiguration message indicating a modified QoS from the donor base station.

  At 808, in response to the modified QoS, the relay node triggers Uu bearer deactivation. According to an aspect, the relay node selects at least one of a plurality of Uu bearers to be deactivated from the corresponding Un bearer based on the modified QoS. According to an aspect, the relay node considers each ARP of Uu bearers transmitted by a congested Un bearer to determine which Uu bearer to deactivate.

  According to an aspect, the relay node may then generate an indication to the MME associated with the UE corresponding to the selected Uu bearer of the selected Uu bearer's bearer release. As shown, the relay node sends a bearer release indication to the MME of the wireless terminal via the donor base station. Subsequently, the MME of the wireless terminal coordinates the deactivation bearer request with the service provision / packet gateway and donor base station of the wireless terminal to deactivate the Uu bearer selected from the congested Un bearer. .

  FIG. 9 is a sequence diagram illustrating an example operation for a direct Uu bearer deactivation mechanism in accordance with certain aspects of the present disclosure. An example of this operation begins at 902 where traffic congestion in the Un bearer is detected at a donor base station. At 904, Uu bearer deactivation is triggered directly by the relay node gateway component of the donor base station. The donor base station selects at least one of the plurality of Uu bearers to deactivate from the corresponding Un bearer based on traffic congestion. According to an aspect, the donor base station may consider the Uu bearer ARP to determine which Uu bearer to deactivate.

  Thereafter, the relay node gateway component of the donor base station generates an indication to the MME of the UE associated with the UE corresponding to the selected Uu bearer of the bearer release of the selected Uu bearer. As illustrated in FIG. 9, the relay node S / P gateway sends a bearer release indication to the UE's MME (as exemplified by 440B). This allows the UE MME to initiate the Uu bearer deactivation procedure. For example, the MME of the UE receives a bearer release indication from the relay node gateway and then communicates a delete bearer command to the S / P gateway of the UE (as exemplified by 440C). The S / P gateway responds with a delete bearer request that is propagated to the relay node as a deactivation bearer request.

  FIG. 10 is a sequence diagram illustrating an example operation for a user equipment context release mechanism in accordance with certain aspects of the present disclosure. This operation begins at 1002 where Un bearer congestion is detected at the donor base station. At 1004, a UE context release is triggered by a relay node gateway component embedded in the donor base station. The donor base station selects one of a plurality of UEs to be released from communication based on traffic congestion. According to an aspect, the donor base station considers the ARP of the Uu bearer transmitted by the Un bearer to determine which Uu bearer to deactivate.

  However, in this case, the donor base station does not simply deactivate the selected Uu bearer but triggers a UE context release for the UE corresponding to the selected Uu bearer. This can affect many additional bearers associated with the same UE. It is further noted that the example implementation of the operation may also release all S1-U bearers of the associated UE and S1 application protocol interface messages. According to an aspect, a relay node gateway component embedded in a donor base station can select a selected UE's MME (as illustrated as 440B) for context release of the selected UE. Generate an indication of. As illustrated in FIG. 10, the relay node gateway component triggers a UE context release by sending a UE context release request to the MME 440B of the UE via the S1-AP interface. This causes the MME of the UE to initiate the UE context release procedure.

  It is understood that the specific order or hierarchy of steps in the processes disclosed is an example of a typical approach. Based on design choices, it is understood that the specific order or hierarchy of steps in these processes can be reconfigured while remaining within the scope of the present disclosure. The method claims present elements of the various steps in sample order, and are not meant to be limited to the specific order or hierarchy presented.

  Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that can be referenced throughout the above description are voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any of these It can be expressed by a combination of

  Those skilled in the art will further recognize that the various exemplary logic blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein are electronic hardware, computer software, It will be appreciated that it may be realized as a combination of both. To clearly illustrate the interchangeability between hardware and software, various illustrative components, blocks, modules, circuits, and steps have been generally described in terms of their functionality. Whether these functions are implemented as hardware or software depends on the particular application and design constraints imposed on the overall system. Those skilled in the art can implement the functions described above in a manner that varies with each particular application. However, this application judgment should not be construed as causing a departure from the scope of the present invention.

  Various exemplary logic 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), fields, and the like. A programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of the above designed to implement the functions described above Can be implemented or implemented. A general purpose processor may be a microprocessor, but in the alternative, may be a prior art processor, controller, microcontroller, or sequential circuit. The processor may be implemented, for example, as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors associated with a DSP core, or any other such combination of computing devices. Can be done.

  The method or algorithm steps described with respect to the embodiments disclosed herein may be embodied directly in hardware, by software modules executed by a processor, or by a combination of the two. The software module may be RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or other types of storage media known in the art. Can exist. A typical storage medium is coupled to a processor such as a processor that can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and storage medium can reside in the ASIC. The ASIC may exist in the user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will also be apparent to those skilled in the art, and the general principles defined herein may be applied to other examples without departing from the spirit or scope of the disclosure. Can be done. Thus, this disclosure is not intended to be limited to the embodiments shown herein, but is intended to correspond to the broadest scope consistent with the principles and novel features disclosed herein. ing.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[C1]
A method for operating a donor base station having a first plurality of radio bearers (RBs) that interface with a relay node, comprising:
Determining traffic congestion in the first plurality of RBs;
Taking one or more actions to trigger removal of at least one of a second plurality of RBs that interface between the relay node and at least one user equipment (UE);
A method comprising:
[C2]
Taking the one or more actions includes:
Selecting at least one of the second plurality of RBs based on an indication of each allocation and retention priority (ARP) of the second plurality of RBs;
Generating an indication to a mobility management entity (MME) to trigger removal of the selected RB;
The method of claim 1, further comprising:
[C3]
The method of claim 1, wherein taking the one or more actions comprises modifying a quality of service (QoS) associated with the first plurality of RBs based on the traffic congestion.
[C4]
In response to the modified QoS, the relay node selects at least one of the second plurality of RBs for removal, and the mobility associated with the UE associated with the selected RB The method according to claim 3, wherein the QoS is modified so that an indication of a bearer release of a selected RB for a management entity (MME) can be generated.
[C5]
Taking the one or more actions includes:
Selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
Generating an indication of a bearer release of the selected RB to a mobility management entity (MME) associated with a UE associated with the selected RB;
The method of claim 1, comprising:
[C6]
Taking the one or more actions includes:
Selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
Generating an indication to a mobility management entity (MME) to request a UE context release of the UE associated with the selected RB;
The method of claim 1, comprising:
[C7]
A donor base station having a first plurality of radio bearers (RBs) that interface with a relay node, comprising:
A traffic monitor component configured to determine traffic congestion in the first plurality of RBs;
Configured to take one or more actions to trigger removal of at least one of a second plurality of RBs that interface between the relay node and at least one user equipment (UE) Radio bearer manager component,
A donor base station comprising.
[C8]
The radio bearer manager component further includes at least one of the second plurality of RBs based on an indication of an allocation and holding priority (ARP) of each of the second plurality of RBs. 8. The donor base station of claim 7, configured to generate an indication to a mobility management entity (MME) to select and trigger removal of the selected RB.
[C9]
8. The donor base station of claim 7, further comprising a gateway component configured to modify a quality of service (QoS) associated with the first plurality of RBs based on the traffic congestion.
[C10]
The gateway component selects at least one of the second plurality of RBs for removal according to the modified QoS, and a UE associated with the selected RB The donor base station according to claim 9, configured to modify the QoS so as to generate an indication of a bearer release of an RB selected for a mobility management entity (MME) associated with the .
[C11]
The radio bearer manager component further includes:
Based on the traffic congestion, select at least one of the second plurality of RBs to be deactivated,
Generate an indication of the bearer release of the selected RB to the mobility management entity (MME) associated with the UE associated with the selected RB
The donor base station according to claim 7, configured as described above.
[C12]
The radio bearer manager component further includes:
Based on the traffic congestion, select at least one of the second plurality of RBs to be deactivated,
Generate an indication to a mobility management entity (MME) to request a UE context release for the UE associated with the selected RB
The donor base station according to claim 7, configured as described above.
[C13]
An apparatus for wireless communication having a first plurality of radio bearers (RBs) that interface with a relay node, comprising:
Means for determining traffic congestion in the first plurality of RBs;
Means for taking one or more actions to trigger removal of at least one of a second plurality of RBs that interface between the relay node and at least one user equipment (UE);
A device comprising:
[C14]
The means for taking the one or more actions is:
Means for selecting at least one of the second plurality of RBs based on an indication of each allocation and retention priority (ARP) of the second plurality of RBs;
Means for generating an indication to a mobility management entity (MME) to trigger removal of the selected RB;
14. The apparatus of claim 13, comprising:
[C15]
14. The apparatus of claim 13, wherein the means for taking one or more actions comprises means for modifying a quality of service (QoS) associated with the first plurality of RBs based on the traffic congestion.
[C16]
The relay node selects at least one for removal from the second plurality of RBs according to the modified QoS, and mobility management associated with a UE associated with the selected RB The apparatus according to claim 15, wherein the QoS is modified so that an indication of a bearer release of an RB selected for an entity (MME) can be generated.
[C17]
The means for taking the one or more actions is:
Means for selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
Means for generating an indication of a bearer release of the selected RB to a mobility management entity (MME) associated with a UE associated with the selected RB;
14. The apparatus of claim 13, comprising:
[C18]
The means for taking the one or more actions is:
Means for selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
Means for generating an indication to a mobility management entity (MME) for requesting a UE context release of a UE associated with the selected RB;
14. The apparatus of claim 13, comprising:
[C19]
A computer program product comprising a computer readable medium having stored instructions for operating a donor base station having a first plurality of radio bearers (RBs) that interface with a relay node, comprising:
The instruction group is:
Determining traffic congestion in the first plurality of RBs;
Taking one or more actions to trigger removal of at least one of the second plurality of RBs that interface between the relay node and at least one user equipment (UE);
A computer program product executable for one or more processors.
[C20]
A group of instructions for taking the one or more actions is:
Selecting at least one of the second plurality of RBs based on an indication of each allocation and retention priority (ARP) of the second plurality of RBs;
Generating an indication to a mobility management entity (MME) to trigger removal of the selected RB;
The computer program product of claim 19, comprising instructions for:
[C21]
The group of instructions for taking one or more actions comprises a group of instructions for modifying a quality of service (QoS) associated with the first plurality of RBs based on the traffic congestion. The computer program product described in 1.
[C22]
The relay node selects at least one for removal from the second plurality of RBs according to the modified QoS, and mobility management associated with a UE associated with the selected RB The computer program product of claim 21, wherein the QoS is modified to generate an indication of a bearer release of an RB selected for an entity (MME).
[C23]
A group of instructions for taking the one or more actions is:
Selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
Generating an indication of a bearer release of the selected RB to a mobility management entity (MME) associated with a UE associated with the selected RB;
The computer program product of claim 19, comprising instructions for:
[C24]
A group of instructions for taking the one or more actions is:
Selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
Generating an indication to a mobility management entity (MME) to request a UE context release of a UE associated with the selected RB;
The computer program product of claim 19, comprising instructions for:

Claims (24)

A method for operating a donor base station having a first plurality of radio bearers (RBs) that interface with a relay node, comprising:
Determining traffic congestion in the first plurality of RBs;
One or more for triggering removal of at least one of the second plurality of RBs that interface between the relay node and at least one user equipment (UE) based on the determined traffic congestion Taking the action of
A method comprising: Taking the one or more actions includes:
Selecting at least one of the second plurality of RBs based on an indication of each allocation and retention priority (ARP) of the second plurality of RBs;
Generating an indication to a mobility management entity (MME) to trigger removal of the selected RB;
Bei El A method according to claim 1.   The method of claim 1, wherein taking the one or more actions comprises modifying a quality of service (QoS) associated with the first plurality of RBs based on the traffic congestion.   In response to the modified QoS, the relay node selects at least one of the second plurality of RBs for removal, and the mobility associated with the UE associated with the selected RB The method according to claim 3, wherein the QoS is modified so that an indication of a bearer release of a selected RB for a management entity (MME) can be generated. Taking the one or more actions includes:
Selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
Generating an indication of a bearer release of the selected RB to a mobility management entity (MME) associated with a UE associated with the selected RB. . Taking the one or more actions includes:
Selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
Generating an indication to a mobility management entity (MME) to request a UE context release of a UE associated with the selected RB. A donor base station having a first plurality of radio bearers (RBs) that interface with a relay node, comprising:
A traffic monitor component configured to determine traffic congestion in the first plurality of RBs;
1 or to trigger removal of at least one of a second plurality of RBs that interface between the relay node and at least one user equipment (UE) based on the determined traffic congestion A radio bearer manager component configured to take multiple actions;
A donor base station comprising. The radio bearer manager component further includes:
Selecting at least one of the second plurality of RBs based on an indication of a respective allocation and retention priority (ARP) of the second plurality of RBs;
8. The donor base station of claim 7, configured to generate an indication to a mobility management entity (MME) to trigger removal of the selected RB.   8. The donor base station of claim 7, further comprising a gateway component configured to modify a quality of service (QoS) associated with the first plurality of RBs based on the traffic congestion. The gateway component, said relay node, in response to said corrected QoS, selects at least one of removing one of the second plurality of RB, associated with the selected RB The donor base according to claim 9, configured to modify the QoS so as to generate an indication of a bearer release of a selected RB for a mobility management entity (MME) associated with the UE. Bureau. The radio bearer manager component further includes:
Based on the traffic congestion, select at least one of the second plurality of RBs to be deactivated,
8. The configuration of claim 7, configured to generate an indication of a bearer release of the selected RB to a mobility management entity (MME) associated with a UE associated with the selected RB. Donor base station. The radio bearer manager component further includes:
Based on the traffic congestion, select at least one of the second plurality of RBs to be deactivated,
8. The donor base station of claim 7, configured to generate an indication to a mobility management entity (MME) to request a UE context release of a UE associated with the selected RB. An apparatus for wireless communication having a first plurality of radio bearers (RBs) that interface with a relay node, comprising:
Means for determining traffic congestion in the first plurality of RBs;
One or more for triggering removal of at least one of the second plurality of RBs that interface between the relay node and at least one user equipment (UE) based on the determined traffic congestion Means to take action,
A device comprising: The means for taking the one or more actions is:
Means for selecting at least one of the second plurality of RBs based on an indication of each allocation and retention priority (ARP) of the second plurality of RBs;
14. The apparatus of claim 13, comprising: means for generating an indication to a mobility management entity (MME) to trigger removal of the selected RB. The means for taking the one or more actions is:
The apparatus of claim 13, comprising means for modifying a quality of service (QoS) associated with the first plurality of RBs based on the traffic congestion. The relay node selects at least one of the second plurality of RBs for removal according to the modified QoS, and the mobility associated with the UE associated with the selected RB 16. The apparatus of claim 15, wherein the QoS is modified so that an indication of a bearer release of a selected RB for a management entity (MME) can be generated. The means for taking the one or more actions is:
Means for selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
14. The apparatus of claim 13, comprising means for generating an indication of a bearer release of the selected RB to a mobility management entity (MME) associated with a UE associated with the selected RB. . The means for taking the one or more actions is:
Means for selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
14. The apparatus of claim 13, comprising means for generating an indication to a mobility management entity (MME) to request a UE context release of a UE associated with the selected RB. For operating the donor base station having a first plurality of radio bearers stored relay nodes and interfaces (RB), a computer-readable storage medium body stores instruction group,
The instruction group is:
Determining traffic congestion in the first plurality of RBs;
One or more for triggering removal of at least one of the second plurality of RBs that interface between the relay node and at least one user equipment (UE) based on the determined traffic congestion A computer-readable storage medium executable by one or more processors for performing the operations of A group of instructions for taking the one or more actions is:
Selecting at least one of the second plurality of RBs based on an indication of each allocation and retention priority (ARP) of the second plurality of RBs;
Generating an indication to a mobility management entity (MME) to trigger removal of the selected RB;
The computer-readable storage medium of claim 19, comprising instructions for. A group of instructions for taking the one or more actions is:
The computer-readable storage medium of claim 19, comprising instructions for modifying a quality of service (QoS) associated with the first plurality of RBs based on the traffic congestion. The relay node selects at least one of the second plurality of RBs for removal according to the modified QoS, and the mobility associated with the UE associated with the selected RB The computer-readable storage medium of claim 21, wherein the QoS is modified to generate an indication of a bearer release of a selected RB for a management entity (MME). A group of instructions for taking the one or more actions is:
Selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
Generating an indication of a bearer release of the selected RB to a mobility management entity (MME) associated with a UE associated with the selected RB;
The computer-readable storage medium of claim 19, comprising instructions for. A group of instructions for taking the one or more actions is:
Selecting at least one of the second plurality of RBs to be deactivated based on the traffic congestion;
Generating an indication to a mobility management entity (MME) to request a UE context release of a UE associated with the selected RB;
The computer-readable storage medium of claim 19, comprising instructions for.

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