Evolved Node B, user equipment and method for transition between idle mode and connected mode

Abstract

Disclosed herein are an evolved Node B, a user equipment, and a method for transitioning between an idle mode and a connected mode. An eNB may receive an uplink data packet from a user equipment (UE) using a lightweight radio resource control (RRC) connection between the eNB and the UE. The eNB may send an RRC connection release message to the UE to indicate the UE's transition from an RRC connection to an RRC idle mode. The RRC connection release message may include an indicator indicating whether the UE will store context information for the RRC connection. The eNB may also receive additional uplink data packets based on the stored context information using a lightweight RRC connection.

Description

[0001] Description of the case

[0002] This application is a divisional application of an invention patent application with a filing date of January 13, 2016, application number 201680009285.2, and titled "Evolved Node B, User Equipment, and Method for Transitioning Between Idle Mode and Connected Mode"

[0003] Priority declaration

[0004] This application claims the benefit of priority to U.S. Patent Application Serial No. 14 / 927,928, filed on October 30, 2015, which claims the benefit of priority to U.S. Provisional Patent Application Serial No. 62 / 113,925, filed on February 9, 2015, each of which is incorporated herein by reference in its entirety. Technical Field

[0005] Embodiments relate to wireless communications. Some embodiments relate to cellular communication networks including 3GPP (3rd Generation Partnership Project) networks, 3GPP LTE (Long Term Evolution) networks, and 3GPP LTE-A (LTE Advanced) networks, but the scope of the embodiments is not limited in this respect. Some embodiments relate to machine type communication (MTC) operations. Some embodiments relate to radio resource control (RRC) modes such as RRC idle mode or RRC connected mode. Background Art

[0006] Cellular networks may be configured to support a variety of devices. As an example, devices configured for machine type communication (MTC) operations may be supported by the network for transmitting relatively small blocks of data at relatively infrequent frequencies. Management of connections between the network and supported devices may be challenging in some situations (e.g., when the network supports a large number of MTC devices and / or other devices). Therefore, in these and other situations, methods and systems for managing device connections are generally needed. Summary of the invention

[0007] The present disclosure provides a base station device, which is configured to be used as a node B (NB) in a fifth generation (5G) network, and the device includes: a processing module; a control plane interface, which is configured by the processing module to carry control signaling; and a user plane interface, which is configured by the processing module to carry business data through user plane resources, wherein the processing module is configured to: receive an indication from a mobile management network entity of the 5G network, which indicates whether user plane Internet of Things (IoT) operations are supported for user equipment (UE); and if the UE is in a connection management connection state, if the UE has an active user plane connection with the network, and if support for the user plane IoT operation is indicated for the UE, initiate a connection termination process to terminate a radio resource control (RRC) connection with the UE, wherein, in order to perform the connection termination process, the processing module is configured to: encode a termination request message for transmission to the mobile management network entity entity, the abort request message triggers deactivation of user plane resources for the UE; stores access stratum (AS) information, UE association, and UE context for the UE; receives an abort response message from the mobile management network entity; and in response to the abort response message, encodes an RRC connection abort message for transmission to the UE so that the UE stores the AS information and enters a connection management idle state; wherein the processing module is further configured to: when the UE is in the connection management idle state, decode a request from the UE for resuming the aborted RRC connection, the request including uplink data from the UE, the request being received via the control plane interface; forward the uplink data received from the UE to the network based at least in part on the stored AS information; and send the request for resumption to the mobile management network entity, wherein the request for resumption indicates aborting the resumed RRC connection and the UE transitioning back to the idle state.

[0008] The present disclosure provides a non-transitory computer-readable storage medium storing instructions for execution by a processing module of a base station, the base station being configured to be used as a node B (NB) in a fifth generation (5G) network, wherein a control plane interface is configured by the processing module to carry control signaling, and wherein a user plane interface is configured by the processing module to carry service data through user plane resources, wherein the processing module is configured to: receive an indication from a mobile management network entity of the 5G network, the indication indicating whether user plane Internet of Things (IoT) operations are supported for a user equipment (UE); and if the UE is in a connection management connection state, if the UE has an active user plane connection with the network, and if support for the user plane IoT operation is indicated for the UE, initiate a connection termination procedure to terminate a radio resource control (RRC) connection with the UE, wherein, in order to perform the connection termination procedure, the processing module is configured to: encode a termination request message for transmission to the mobile management network entity entity, the abort request message triggers deactivation of user plane resources for the UE; stores access stratum (AS) information, UE association, and UE context for the UE; receives an abort response message from the mobile management network entity; and in response to the abort response message, encodes an RRC connection abort message for transmission to the UE so that the UE stores the AS information and enters a connection management idle state; wherein the processing module is further configured to: when the UE is in the connection management idle state, decode a request from the UE for resuming the aborted RRC connection, the request including uplink data from the UE, the request being received via the control plane interface; forward the uplink data received from the UE to the network based at least in part on the stored AS information; and send the request for resumption to the mobile management network entity, wherein the request for resumption indicates aborting the resumed RRC connection and the UE transitioning back to the idle state.

[0009] The present disclosure provides a device of a user equipment, which is configured to perform user plane Internet of Things (IoT) operations in a fifth generation (5G) network, wherein the UE comprises: a processing module; a control plane interface, which is configured by the processing module to carry control signaling; a user plane interface, which is configured by the processing module to carry service data through user plane resources; and a memory, wherein the processing module is configured to: encode signaling for transmission to a base station serving as a Node B (NB) of the 5G network, wherein the signaling indicates that the UE supports user plane IoT operations, wherein if the UE is in a connection management connection state, if the UE is connected to the 5G There is an active user plane connection in the network, and if support for the user plane IoT operation is indicated, the processing module is configured to: decode the RRC connection termination message; store access stratum (AS) information in the memory; and enter a connection management idle state, and wherein, if the UE is in the connection management idle state, the processing module is configured to encode a request to resume the terminated RRC connection for transmission to the NB, the request including uplink data from the UE, the uplink data being sent to the NB via the control plane interface, wherein the uplink data is sent without activating the user plane resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a functional diagram of a 3GPP network according to some embodiments;

[0011] Figure 2 is a functional diagram of a user equipment (UE) according to some embodiments;

[0012] Figure 3 is a functional diagram of an evolved Node B (eNB) according to some embodiments;

[0013] Figure 4 is a functional diagram of a Mobility Management Entity (MME) according to some embodiments;

[0014] Figure 5 The operation of a communication method according to some embodiments is shown;

[0015] Figure 6 An example of an RRC connection release message according to some embodiments is shown;

[0016] Figure 7 shows an example message flow diagram according to some embodiments;

[0017] Figure 8 shows example control messages related to UE context and UE state according to some embodiments;

[0018] Fig. 9 illustrates the operation of another communication method according to some embodiments;

[0019] Fig.10 Additional example control messages related to UE context and UE state according to some embodiments are shown; and

[0020] Fig.11 Another example message flow diagram is shown in accordance with some embodiments. DETAILED DESCRIPTION

[0021] The following description and the accompanying drawings sufficiently illustrate the specific embodiments to enable those skilled in the art to implement them. Other embodiments may include structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in or replaced by portions and features of other embodiments. The embodiments set forth in the claims include all available equivalents of these claims.

[0022] Figure 1 1 is a functional diagram of a 3GPP network according to some embodiments. The network includes a radio access network (RAN) (e.g., as shown, E-UTRAN or Evolved Universal Terrestrial Radio Access Network) 100 and a core network 120 (e.g., shown as an Evolved Packet Core (EPC)) coupled together via an S1 interface 115. For convenience and simplicity, only the core network 120 and a portion of the RAN 100 are shown.

[0023] The core network 120 includes a mobility management entity (MME) 122, a serving gateway (serving GW) 124, and a packet data network gateway (PDN GW) 126. The RAN 100 includes an evolved Node-B (eNB) 104 (which may operate as a base station) for communicating with a user equipment (UE) 102. The eNB 104 may include a macro eNB and a low power (LP) eNB. According to some embodiments, the eNB 104 may receive uplink data packets from the UE 102 over a radio resource control (RRC) connection between the eNB 104 and the UE 102. The eNB 104 may send an RRC connection release message to the UE 102 to indicate a transition of the UE 102 from the RRC connection to the RRC idle mode. The eNB 104 may also receive additional uplink data packets based on the stored context information.

[0024] The MME 122 is functionally similar to the control plane of a traditional serving GPRS support node (SGSN). The MME 122 manages mobility aspects in access, such as gateway selection and tracking area list management. The service GW 124 terminates the interface toward the RAN 100 and routes data packets between the RAN 100 and the core network 120. In addition, the service GW 124 can be a local mobility anchor for inter-eNB handover and can also provide an anchor for inter-3GPP mobility. Other responsibilities may include legal interception, charging, and some policy enforcement. The service GW 124 and the MME 122 can be implemented in one physical node or in separate physical nodes. The PDN GW 126 terminates the SGi interface toward the packet data network (PDN). The PDN GW 126 routes data packets between the EPC 120 and the external PDN and can be a key node for policy enforcement and charging data collection. The PDN GW 126 can also provide an anchor for mobility for non-LTE access. The external PDN may be any kind of IP network and IP Multimedia Subsystem (IMS) domain. The PDN GW 126 and the Serving GW 124 may be implemented in one physical node or in separate physical nodes. In addition, the MME 122 and the Serving GW 124 may be collapsed into one physical node, in which case one less hop is required to transmit the message.

[0025] The eNB 104 (macro and micro eNB) terminates the air interface protocol and may be the first point of contact for the UE 102. In some embodiments, the eNB 104 may implement various logical functions of the RAN 100, including but not limited to RNC (radio network controller functions) such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management. According to an embodiment, the UE 102 may be configured to communicate orthogonal frequency division multiplexing (OFDM) communication signals with the eNB 104 over a multi-carrier communication channel according to an orthogonal frequency division multiple access (OFDMA) communication technique. An OFDM signal may include multiple orthogonal subcarriers.

[0026] The S1 interface 115 is an interface that separates the RAN 100 and the EPC 120. The S1 interface 115 is divided into two parts: S1-U that carries service data between the eNB 104 and the serving GW 124, and S1-MME that is a signaling interface between the eNB 104 and the MME 122. The X2 interface is an interface between the eNBs 104. The X2 interface includes two parts: X2-C and X2-U. X2-C is a control plane interface between the eNBs 104, and X2-U is a user plane interface between the eNBs 104.

[0027] For cellular networks, LP cells are typically used to extend coverage to indoor areas where outdoor signals cannot reach well, or to increase network capacity in areas where telephone usage is very dense, such as train stations. The term low power (LP) eNB used herein refers to any suitable lower power eNB for implementing narrower cells (narrower than macro cells) (e.g., femtocells, picocells, or microcells). Femtocell eNBs are typically provided by mobile network operators to their residential or enterprise customers. Femtocells are typically the size of a residential gateway or smaller and are generally connected to the user's broadband line. Once switched on, the femtocell connects to the mobile operator's mobile network and provides additional coverage for residential femtocells with a range of typically 30 to 50 meters. Therefore, an LP eNB can be a femtocell eNB, since it is coupled through a PDN GW 126. Similarly, a picocell is a wireless communication system that typically covers a smaller area, for example, within a building (office, shopping mall, train station, etc.) or more recently within an airplane. A pico cell eNB may generally be connected to another eNB (e.g., a macro eNB) via its base station controller (BSC) functionality via an X2 link. Thus, an LP eNB may be implemented by a pico cell eNB, since it is coupled to a macro eNB via an X2 interface. A pico cell eNB or other LP eNB may include some or all of the functionality of a macro eNB. In some cases, this may be referred to as an access point base station or an enterprise femto cell.

[0028] In some embodiments, a downlink resource grid may be used for downlink transmission from eNB 104 to UE 102, while uplink transmission from UE 102 to eNB 104 may use similar techniques. The grid may be a time-frequency grid (referred to as a resource grid or a time-frequency resource grid), which is a physical resource in the downlink in each time slot. Such a time-frequency plane representation is a common way of OFDM systems, which makes radio resource allocation more intuitive. Each column and each row of the resource grid corresponds to an OFDM symbol and an OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to a time slot in a radio frame. The smallest time-frequency unit in the resource grid is represented as a resource element (RE). Each resource grid includes many resource blocks (RBs), which describe the mapping of certain physical channels to resource elements. Each resource block includes a set of resource elements, and in the frequency domain it can represent the minimum amount of resources that can be currently allocated. There are several different physical downlink channels that are transmitted using such resource blocks. Of particular relevance to the present disclosure, two of these physical downlink channels are the Physical Downlink Shared Channel and the Physical Downlink Control Channel.

[0029] The physical downlink shared channel (PDSCH) carries user data and higher layer signaling to the UE 102 ( Figure 1 ). The physical downlink control channel (PDCCH) carries information about resource allocation and transport format related to the PDSCH channel, etc. The PDCCH also informs the UE 102 of HARQ information, resource allocation, and transport format related to the uplink shared channel. Typically, downlink scheduling (allocation of control and shared channel resource blocks to UEs 102 in the cell) is performed at the eNB 104 based on the channel quality information fed back from the UE 102 to the eNB 104, and then downlink resource allocation information is sent to the UE 102 on the control channel (PDCCH) for (allocated to) the UE 102.

[0030] PDCCH uses CCE (control channel elements) to convey control information. Before being mapped to resource elements, PDCCH complex symbols are first organized into quadruplets, and then the quadruplets are arranged using a sub-block interleaver for rate matching. Each PDCCH is transmitted using one or more of these control channel elements (CCEs), where each CCE corresponds to nine groups of four physical resource elements called resource element groups (REGs). Four QPSK symbols are mapped to each REG. One or more CCEs can be used to transmit PDCCH, depending on the size of the DCI and the channel conditions. Four or more different PDCCH formats may be defined in LTE, with different numbers of CCEs (e.g., aggregation levels, L=1, 2, 4, or 8).

[0031] Figure 2 is a functional diagram of a user equipment (UE) according to some embodiments. UE 200 may be suitable for use as Figure 1UE 102 shown. In some embodiments, UE 200 may include at least application circuit 202, baseband circuit 204, radio frequency (RF) circuit 206, front end module (FEM) circuit 208, and one or more antennas 210 coupled together as shown. In some embodiments, other circuits or arrangements may include one or more elements and / or components of application circuit 202, baseband circuit 204, RF circuit 206, and / or FEM circuit 208, and in some cases may also include other elements and / or components. As an example, "processing circuit" may include one or more elements and / or components, some or all of which may be included in application circuit 202 and / or baseband circuit 204. As another example, "transceiver circuit" may include one or more elements and / or components, some or all of which may be included in RF circuit 206 and / or FEM circuit 208. However, these examples are not limiting, because in some cases the processing circuit and / or transceiver circuit may also include other elements and / or components.

[0032] The application circuitry 202 may include one or more application processors. For example, the application circuitry 202 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and special-purpose processors (e.g., graphics processors, application processors, etc.). The processor may be coupled to and / or may include a memory / storage device, and may be configured to execute instructions stored in the memory / storage device to enable various applications and / or operating systems to run on the system.

[0033] The baseband circuit 204 may include circuits, such as but not limited to one or more single-core or multi-core processors. The baseband circuit 204 may include one or more baseband processors and / or control logic for processing baseband signals received from the receive signal path of the RF circuit 206 and generating baseband signals for the transmit signal path of the RF circuit 206. The baseband processing circuit 204 may be connected to the application circuit 202 through an interface for baseband signal generation and processing and for controlling the operation of the RF circuit 206. For example, in some embodiments, the baseband circuit 204 may include a second generation (2G) baseband processor 204a, a third generation (3G) baseband processor 204b, a fourth generation (4G) baseband processor 204c, and / or (one or more) other baseband processors 204d for other existing generations, generations under development, or generations to be developed in the future (e.g., fifth generation (5G), 6G, etc.). The baseband circuitry 204 (e.g., one or more of the baseband processors 204a-d) may handle various radio control functions to enable communication with one or more radio networks via the RF circuitry 206. The radio control functions may include, but are not limited to, signal modulation / demodulation, encoding / decoding, radio frequency shifting, etc. In some embodiments, the modulation / demodulation circuitry of the baseband circuitry 204 may include fast Fourier transform (FFT), precoding, and / or constellation mapping / demapping functions. In some embodiments, the encoding / decoding circuitry of the baseband circuitry 204 may include convolution, tail-biting convolution, turbo, Viterbi, and / or low-density parity check (LDPC) encoder / decoder functions. The embodiments of the modulation / demodulation and encoder / decoder functions are not limited to these examples, and may include other suitable functions in other embodiments.

[0034] In some embodiments, the baseband circuit 204 may include elements of a protocol stack, such as elements of an Evolved Universal Terrestrial Radio Access Network (EUTRAN) protocol (including, for example, physical (PHY), medium access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and / or radio resource control (RRC) elements). The central processing unit (CPU) 204e of the baseband circuit 204 may be configured to run elements of a protocol stack for signaling of the PHY, MAC, RLC, PDCP, and / or RRC layers. In some embodiments, the baseband circuit may include one or more audio digital signal processors (DSPs) 204f. (One or more) audio DSPs 204f may include elements for compression / decompression and echo cancellation, and may include other suitable processing elements in other embodiments. In some embodiments, the components of the baseband circuit may be appropriately combined in a single chip, a single chipset, or arranged on the same circuit board. In some embodiments, some or all of the constituent components of the baseband circuit 204 and the application circuit 202 may be implemented together, for example, together on a system on a chip (SOC).

[0035] In some embodiments, baseband circuitry 204 may provide communications compatible with one or more radio technologies. For example, in some embodiments, baseband circuitry 204 may support communications with an Evolved Universal Terrestrial Radio Access Network (EUTRAN) and / or other wireless metropolitan area networks (WMANs), wireless local area networks (WLANs), wireless personal area networks (WPANs). Embodiments in which baseband circuitry 204 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

[0036] The RF circuit 206 may use modulated electromagnetic radiation through a non-solid medium to enable communication with a wireless network. In various embodiments, the RF circuit 206 may include switches, filters, amplifiers, etc. to assist in communication with the wireless network. The RF circuit 206 may include a receive signal path, which may include circuits for down-converting RF signals received from the FEM circuit 208 and providing baseband signals to the baseband circuit 204. The RF circuit 206 may also include a transmit signal path, which may include circuits for up-converting baseband signals provided by the baseband circuit 204 and providing RF output signals to the FEM circuit 208 for transmission.

[0037] In some embodiments, the RF circuit 206 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuit 206 may include a mixer circuit 206a, an amplifier circuit 206b, and a filter circuit 206c. The transmit signal path of the RF circuit 206 may include a filter circuit 206c and a mixer circuit 206a. The RF circuit 206 may also include a synthesizer circuit 206d for synthesizing the frequency used by the mixer circuit 206a for the receive signal path and the transmit signal path. In some embodiments, the mixer circuit 206a of the receive signal path may be configured to down-convert the RF signal received from the FEM circuit 208 based on the synthesized frequency provided by the synthesizer circuit 206d. The amplifier circuit 206b may be configured to amplify the down-converted signal, and the filter circuit 206c may be a low pass filter (LPF) or a band pass filter (BPF) configured to remove unwanted signals from the down-converted signal to generate an output baseband signal. The output baseband signal may be provided to the baseband circuit 204 for further processing. In some embodiments, the output baseband signal may be a zero frequency baseband signal, but this is not required. In some embodiments, the mixer circuit 206a of the receive signal path may include a passive mixer, but the scope of the embodiments is not limited in this respect. In some embodiments, the mixer circuit 206a of the transmit signal path may be configured to up-convert the input baseband signal based on the synthesized frequency provided by the synthesizer circuit 206d to generate an RF output signal for the FEM circuit 208. The baseband signal may be provided by the baseband circuit 204 and may be filtered by the filter circuit 206c. The filter circuit 206c may include a low pass filter (LPF), but the scope of the embodiments is not limited in this respect.

[0038] In some embodiments, the mixer circuit 206a of the receive signal path and the mixer circuit 206a of the transmit signal path may include two or more mixers and may be arranged for quadrature down-conversion and / or up-conversion, respectively. In some embodiments, the mixer circuit 206a of the receive signal path and the mixer circuit 206a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuit 206a of the receive signal path and the mixer circuit 206a of the transmit signal path may be arranged for direct down-conversion and / or direct up-conversion, respectively. In some embodiments, the mixer circuit 206a of the receive signal path and the mixer circuit 206a of the transmit signal path may be configured for superheterodyne operation.

[0039] In some embodiments, the output baseband signal and the input baseband signal may be analog baseband signals, but the scope of the embodiments is not limited in this respect. In some alternative embodiments, the output baseband signal and the input baseband signal may be digital baseband signals. In these alternative embodiments, the RF circuit 206 may include an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC) circuit, and the baseband circuit 204 may include a digital baseband interface for communicating with the RF circuit 206. In some dual-mode embodiments, a separate radio IC circuit may be provided for processing signals for each spectrum, but the scope of the embodiments is not limited in this respect.

[0040] In some embodiments, the synthesizer circuit 206d may be a fractional-N synthesizer or a fractional N / N+1 synthesizer, but the scope of the embodiments is not limited in this respect, because other types of frequency synthesizers may be suitable. For example, the synthesizer circuit 206d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer including a phase-locked loop with a frequency divider. The synthesizer circuit 206d may be configured to synthesize an output frequency for use by the mixer circuit 206a of the RF circuit 206 based on a frequency input and a frequency divider control input. In some embodiments, the synthesizer circuit 206d may be a fractional N / N+1 synthesizer. In some embodiments, the frequency input may be provided by a voltage-controlled oscillator (VCO), but this is not required. Depending on the desired output frequency, the frequency divider control input may be provided by the baseband circuit 204 or the application processor 202. In some embodiments, the frequency divider control input (e.g., N) may be determined from a lookup table based on a channel indicated by the application processor 202.

[0041] The synthesizer circuit 206d of the RF circuit 206 may include a frequency divider, a delay locked loop (DLL), a multiplexer, and a phase accumulator. In some embodiments, the frequency divider may be a dual-mode frequency divider (DMD), and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by N or N+1 (e.g., based on a carry output) to provide a fractional frequency division ratio. In some example embodiments, the DLL may include a set of cascaded and tunable delay elements, a phase detector, a charge pump, and a D-type flip-flop. In these embodiments, the delay element may be configured to decompose the VCO cycle into Nd equal phase groups, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[0042] In some embodiments, the synthesizer circuit 206d can be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency can be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with a quadrature generator and divider circuit to generate multiple signals at the carrier frequency with multiple different phases relative to each other. In some embodiments, the output frequency can be the LO frequency (f LO ). In some embodiments, RF circuit 206 may include an IQ / polarity converter.

[0043] FEM circuitry 208 may include a receive signal path that may include circuitry configured to operate on RF signals received from one or more antennas 210, amplify the received signals, and provide an amplified version of the received signals to RF circuitry 206 for further processing. FEM circuitry 208 may also include a transmit signal path that may include circuitry configured to amplify signals provided for transmission by RF circuitry 206 for transmission by one or more of one or more antennas 210.

[0044] In some embodiments, the FEM circuit 208 may include a TX / RX switch for switching between transmit mode and receive mode operation. The FEM circuit may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuit may include a low noise amplifier (LNA) for amplifying the received RF signal, and providing the amplified received RF signal as an output (e.g., to the RF circuit 206). The transmit signal path of the FEM circuit 208 may include a power amplifier (PA) for amplifying the input RF signal (e.g., provided by the RF circuit 206), and one or more filters for generating an RF signal for subsequent transmission (e.g., subsequent transmission by one or more of the one or more antennas 210). In some embodiments, the UE 200 may include additional elements, such as memory / storage devices, displays, cameras, sensors, and / or input / output (I / O) interfaces.

[0045] Figure 3 is a functional diagram of an evolved Node B (eNB) according to some embodiments. It should be noted that in some embodiments, eNB 300 may be a fixed non-mobile device. eNB 300 may be suitable for use as Figure 1The eNB 104 shown. The eNB 300 may include a physical layer circuit 302 and a transceiver 305, one or both of which may enable sending and receiving signals to and from the UE 200, other eNBs, other UEs, or other devices using one or more antennas 301. As an example, the physical layer circuit 302 may perform various encoding and decoding functions, which may include the formation of a baseband signal for transmission and the decoding of a received signal. As another example, the transceiver 305 may perform various transmission and reception functions, such as the conversion of a signal between a baseband range and a radio frequency (RF) range. Therefore, the physical layer circuit 302 and the transceiver 305 may be separate components or may be part of a combined component. In addition, some of the functions described may be performed by a combination that may include one, any, or all of the following: the physical layer circuit 302, the transceiver 305, and other components or layers. The eNB 300 may also include a medium access control layer (MAC) circuit 304 for controlling access to the wireless medium. The eNB 300 may also include processing circuitry 306 and memory 308 arranged to perform the operations described herein. The eNB 300 may also include one or more interfaces 310 that may enable communication with other components, including other eNBs 104 ( Figure 1 )、EPC120( Figure 1 ) or other network components). In addition, interface 310 can be implemented with Figure 1 The interface 310 may be wired or wireless or a combination thereof.

[0046] Antennas 210, 301 may include one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas, or other types of antennas suitable for transmission of RF signals. In some multiple-input multiple-output (MIMO) embodiments, antennas 210, 301 may be effectively separated to take advantage of possible spatial diversity and different channel characteristics.

[0047] In some embodiments, UE 200 or eNB 300 may be a mobile device and may be a portable wireless communication device, such as a personal digital assistant (PDA), a laptop or portable computer with wireless communication capabilities, a web tablet, a wireless phone, a smart phone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a wearable device such as a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), or other devices that can wirelessly receive and / or send information. In some embodiments, UE 200 or eNB 300 may be configured to operate according to 3GPP standards, but the scope of the embodiments is not limited in this respect. In some embodiments, the mobile device or other device may be configured to operate according to other protocols or standards (including IEEE 802.11 or other IEEE standards). In some embodiments, UE 200, eNB 300 or other devices may include one or more of the following: a keyboard, a display, a non-volatile memory port, multiple antennas, a graphics processor, an application processor, a speaker, and other mobile device elements. The display may be an LCD screen (including a touch screen).

[0048] Figure 4 is a functional diagram of a mobility management entity (MME) according to some embodiments. In some embodiments, MME 400 may be adapted to function as Figure 1 The MME 400 may include processing circuitry 406 and memory 408 arranged to perform the operations described herein. The MME 400 may also include one or more interfaces 410 that may enable communication with other components, including the eNB 104 ( Figure 1 )、S-GW 122( Figure 1 )、EPC 120( Figure 1 ) or other network components). In addition, interface 410 can be implemented with Figure 1 The interface 410 may be wired or wireless or a combination thereof.

[0049] Although UE 200, eNB 300 and MME 400 are each shown as having several separate functional elements, one or more of these functional elements may be combined and may be implemented by a combination of software-configured elements (e.g., a processing element including a digital signal processor (DSP)) and / or other hardware elements. For example, some elements may include one or more microprocessors, DSPs, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), radio frequency integrated circuits (RFICs), and combinations of various hardware and logic circuits for performing at least the functions described herein. In some embodiments, a functional element may refer to one or more processes operating on one or more processing elements.

[0050] Embodiments may be implemented in one of hardware, firmware, and software, or in a combination thereof. Embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein. A computer-readable storage device may include any non-transient mechanism for storing information in a machine (e.g., computer) readable form. For example, a computer-readable storage device may include a read-only memory (ROM), a random access memory (RAM), a disk storage medium, an optical storage medium, a flash memory device, and other storage devices and media. Some embodiments may include one or more processors and may be configured with instructions stored on a computer-readable storage device.

[0051] According to an embodiment, the eNB 104 may receive an uplink data packet from the UE 102 over a radio resource control (RRC) connection between the eNB 104 and the UE 102. The eNB 104 may send an RRC connection release message to the UE 102 to indicate a transition of the UE 102 from the RRC connection to the RRC idle mode. The RRC connection release message may be based on the expiration of an inactivity timer of the UE 102. The RRC connection release message may include an indicator indicating whether the UE 102 will store context information for the RRC connection. The eNB 104 may also receive additional uplink data packets over the RRC connection based on the stored context information. These embodiments will be described in more detail below.

[0052] Figure 5 The operation of the communication method according to some embodiments is shown. It is worth noting that Figure 5 Compared to the operations or processes shown, embodiments of method 500 may include additional or even fewer operations or processes. Furthermore, embodiments of method 500 are not necessarily limited to Figure 5 When describing method 500, reference may be made to Figure 1-4 and Figure 6-11However, it is understood that the method 500 may be implemented using any other suitable systems, interfaces, and components.

[0053] In addition, while the method 500 and other methods described herein may refer to an eNB 104 or UE 102 operating in accordance with 3GPP or other standards, embodiments of these methods are not limited to those eNBs 104 or UEs 102, and may also be implemented by other mobile devices such as Wi-Fi access points (APs) or user stations (STAs). In addition, the method 500 and other methods described herein may be implemented by wireless devices configured to operate in other suitable types of wireless communication systems, including systems configured to operate in accordance with various IEEE standards such as IEEE 802.11. The method 500 and other methods described herein may also be applicable to the above-mentioned apparatus for UE 102, eNB 104, and / or MME 122 or other devices.

[0054] At operation 505 of method 500, eNB 104 may receive one or more control messages for a radio resource control (RRC) connection between eNB 104 and UE 102 from MME 122. In some embodiments, eNB 104 may send one or more control messages for the RRC connection to MME 122. Thus, eNB 104 and MME 122 may exchange one or more such control messages. In some embodiments, the control message may enable establishment of the RRC connection. In addition, capability information, configuration information, and / or other information about UE 102 may be exchanged between eNB 104 and MME 122 in these and / or other control messages. As a non-limiting example, setup control messages may be exchanged by eNB 104 and MME 122.

[0055] In some embodiments, the eNB 104 may send an indicator to the MME indicating that the RRC connection is a lightweight RRC connection. The eNB 104 may be allowed to delay notifying the MME of the release of the lightweight RRC connection. As a non-limiting example, the indicator indicating that the RRC connection is a lightweight RRC connection may be included in a control message such as a "UE context retained / UE connection suspended" control message. As another non-limiting example, the indicator indicating that the RRC connection is a lightweight RRC connection may be included in a control message such as a "UE context release / UE state change notification" control message. However, these examples are not limiting, because the indicator may be transmitted using other suitable control messages that may or may not necessarily be included in the 3GPP standard or other standards.

[0056] At operation 510, the eNB 104 may receive a first uplink data packet from the UE 102 over the RRC connection. In some embodiments, the first uplink data packet and possibly other uplink data packets may be sent by the UE 102 and / or received at the eNB 104 when the UE 102 is in the RRC connected mode. That is, before transitioning to the RRC idle mode, the UE 102 may send one or more uplink data packets over the RRC connection. In some cases, the UE 102 may also receive one or more downlink data packets sent from the eNB 104 when the UE 102 is in the RRC connected mode.

[0057] In some embodiments, the UE 102 may be configured to operate according to a machine type communication (MTC) or Internet of Things (IoT) mode or protocol. As part of such operation, the UE 102 may exchange small amounts of data with the eNB 104 (or other device) at a relatively infrequent frequency. For example, a data block comprising 100 bytes or less may be sent to the eNB 104 at a frequency less than once per minute. However, the block size is not limited to 100 bytes, because in some cases other block sizes may be used, such as 20, 50, 200, 1000, or other numbers of bytes. The frequency of transmission is also not limited to less than once per minute, because in some cases other transmission frequencies may be used, such as once per second, once in ten seconds, once in two minutes, once in ten minutes, once an hour, once a day, or other periods.

[0058] In some embodiments, the uplink data packets may be sent by the UE 102 according to a schedule or time interval. As an example, the UE 102 may be configured to send an uplink data packet (or multiple packets) at least once per time interval. As another example, the UE 102 may be configured to send uplink data packets at regular intervals or at approximately regular intervals. As another example, the transmission of uplink data packets may be performed infrequently and in a manner that may or may not necessarily be related to the schedule or interval.

[0059] In some embodiments, the eNB 104 may be configured to send downlink data packets to the UE 102 at a frequency that is less frequent than the frequency at which uplink data packets are sent by the UE 102. In some non-limiting example cases, the UE 102 may send uplink data at regular intervals, while the eNB 104 may send downlink data to the UE 102 less frequently or at irregular intervals. In some of these cases, the exchange of data may generally be one-way, so that the eNB 104 may rarely or may not perform downlink data transmission. It should be noted that in some of these cases, downlink control messages may be sent. As an example, the UE 102 may send measurements from a sensor or other component, which may be forwarded by the eNB 104 to another component for processing.

[0060] In some embodiments, the eNB 104 may support a large number of MTC UEs 102 and / or other UEs 102, and in some cases, the management of RRC connections for the UEs may be challenging. For example, there may be frequent transitions between modes such as RRC connected and RRC idle. Such communications to other components (e.g., MME 122 and S-GW 124 and other components) may overload or stress network resources. In addition, the establishment and / or reestablishment of RRC connections for UEs 102 may also utilize a large number of network resources. Therefore, in these and other cases, techniques for managing RRC connections may be beneficial.

[0061] At operation 515, the eNB 104 may detect inactivity of the UE 102. In some embodiments, the eNB 104 may maintain and / or monitor an inactivity timer for the UE 102 to determine inactivity. Inactivity may be associated with an event such as receiving a data message or other communication from the UE 102 at the eNB 104. As an example, when such an event is not detected during a monitoring period of the inactivity timer, the UE 102 may be considered inactive. Thus, the inactivity timer may expire, and the UE 102 may transition to or may be notified to transition to an RRC idle mode. As an example, a UE 102 configured to operate according to an MTC mode or protocol may perform uplink transmissions at an infrequent frequency, and periods of inactivity between these uplink transmissions may be detected at the eNB 104.

[0062] At operation 520, the eNB 104 may retain context information for the RRC connection. In some embodiments, the context information may include an identifier of a data radio bearer (DRB) included in the RRC connection, an access stratum (AS) security context, and / or other information or other parameters. As an example, a security key for the RRC connection may be included in the context information. In some cases, the security key may be for a corresponding UE ID, or may be associated with a corresponding UE ID, but the embodiments are not limited thereto. In some embodiments, the context information may include information that may be exchanged as part of establishing or reestablishing an RRC connection or other connection.

[0063] As an example, the context information may be retained when an inactivity timer of the UE 102 has expired. As another example, the context information may be retained when the UE 102 has transitioned to RRC idle mode and / or is notified to transition to RRC idle mode. As another example, the context information may be retained when a radio bearer associated with an RRC connection has been suspended. The suspended radio bearer may remain established but may be inactive. As another example, the eNB 104 may retain context information between uplink transmissions by a UE 102 configured to operate according to an MTC mode or protocol.

[0064] Thus, when the UE 102, eNB 104, and / or other components retain context information for an RRC connection, it may be possible for the UE 102 to return to an RRC connected mode without performing certain operations (e.g., sepup operations). Thus, benefits may be achieved in terms of the amount of network resources that may otherwise be used for sepup operations. Additionally, benefits may also be achieved in terms of the reduced size of signaling messages that may be sent in a radio bearer (over the air) and / or an S1 bearer.

[0065] At operation 525, the eNB 104 may send an RRC connection release message to the UE 102 to indicate the transition of the UE 102 from the RRC connection to the RRC idle mode. As previously described, the transition may be indicated in response to the expiration of an inactivity timer for the UE 102 at the eNB 104. It should be noted that, as previously described, the embodiments are not limited to Figure 5 For example, in some embodiments, operation 525 may not necessarily be performed in the order shown in FIG. Figure 5 The order shown occurs. Such an example will be described below.

[0066] In some embodiments, the RRC connection release message may include an indicator indicating that context information for the RRC connection is stored by UE 102. That is, the indicator may notify UE 102 to store and / or maintain the context information. In some cases, the indicator may also notify UE 102 that eNB 104 and / or other components are to store and / or maintain the context information. In some cases, the RRC connection release message may be used to notify UE 102 to release and / or terminate one or more bearers associated with the RRC connection. In some embodiments, the RRC connection release message may be included in one or more standards, but the embodiments are not limited thereto.

[0067] Figure 6 An example of an RRC connection release message according to some embodiments is shown. Although the embodiments are not limited thereto, the RRC connection release message 600 may be or may be similar to an "RRCConnectionRelease" message that may be included in the 3GPP standard or other standards. It should be noted that some embodiments may include some, any or all of the parameters shown in the example message 600, and some embodiments may also include additional parameters not shown in the example message 600. In addition, the order and format shown in the example message 600 are not restrictive, but are presented for illustrative purposes. Parameter values ​​may be given in any suitable format. As an example, some parameters may be Boolean values, which take values ​​such as yes / no or the like. As another example, some parameters may take the value of any appropriate number of digits or other numbers. As another example, some parameters may take descriptive values, which may be mapped to numbers in some cases.

[0068] The message 600 may include a context storage indicator 610, which may indicate whether the RRC context information will be stored when the RRC connection is released and / or the bearer of the RRC connection is terminated. The message 600 may include other parameters or information 620 that may or may not be related to the storage of the context or the RRC connection. For example, control information of the message 600 may be included.

[0069] Figure 7 An example message flow diagram according to some embodiments is shown. Reference may be made to message flow diagram 700 to illustrate messages, interfaces, and events that may be associated with some embodiments, but diagram 700 is not limiting. Some embodiments may include operations that may be performed at UE 102, eNB 104, MME 122, and / or S-GW 124, but embodiments are not limited to these devices. In some cases, the techniques and concepts described herein may be applicable to Figure 7The operations and / or events shown include RRC connection, RRC idle mode, RRC connected mode, RRC connection release, context information and / or others. Some embodiments may include Figure 7 One or more operations shown, and some embodiments may also include other operations described herein. In addition, the embodiments are not limited to Figure 7 The chronological order of operations is shown.

[0070] Devices can exchange various messages, parameters and / or information through interfaces, where the interfaces may include but are not limited to Figure 7 As an example, UE 102 and eNB 104 can communicate via LTE-Uu interface 710. As another example, eNB 104 and MME 122 can communicate via S1 interface 715. As another example, MME 122 and S-GW 124 can communicate via S11 interface 720.

[0071] refer to Figure 7 , the message flow diagram 700 shows the expiration of the inactivity timer of UE 102 at event 725. In some cases, eNB 104 may decide whether to retain context information for UE 102. At operation 730, the radio bearer and / or context may be retained. It should also be noted that at operation 760, eNB 104 may send an RRC connection release message to UE 102. As previously mentioned, in some embodiments, the order of operations may be different from Figure 7 That is, in some cases, operation 760 may not necessarily be performed after the other operations shown.

[0072] Returning to method 500, at operation 530, eNB 104 may restrict sending one or more control messages for transition of UE 102 from RRC connection to RRC idle mode to MME 122. At operation 535, eNB 104 may send one or more control messages to MME 122, which may indicate transition of UE 102 to RRC idle mode. As a non-limiting example of such a message, Figure 7 At operation 735 of the message flow diagram 700 in FIG. 1 , the eNB 104 may send a “UE context preserved / UE state change notification” message to the MME 122. Examples of this message will be described in more detail below.

[0073] In some embodiments, the eNB 104 may be configured to refrain from sending control messages and / or refrain from notifying the MME 122 of the transition of the UE 102 to the RRC idle mode. Thus, operation 535 may be excluded from some of these embodiments. In some embodiments, the eNB 104 may be configured to delay such notification of the transition. For example, the eNB 104 may limit the sending of such control messages during a waiting period. After the waiting period, the eNB 104 may send one or more control messages to the MME 122 to notify the UE 102 of the transition to the RRC idle mode. As an example, the eNB 104 may delay the sending for any suitable reason such as resource availability, network congestion, or other factors, and the waiting period may refer to the duration of the delay. It should be noted that the waiting period may not be limited to a fixed duration, because in some cases resource availability, network congestion, and other factors may be dynamic.

[0074] In some embodiments, the waiting period may be a predefined and / or predetermined period, but these embodiments are not limiting. As an example, the waiting time may refer to a period of time between when the transition occurs and when the eNB 104 notifies the MME 122 of the transition. In this case, the eNB 104 may decide when to notify the MME 122 based on any number of factors (e.g., network congestion, the number of UEs 102 supported, the number of messages queued for transmission at the eNB 104, or other factors). This ability to delay notification may provide the eNB 104 with scheduling flexibility for use of available network resources (e.g., system throughput or other). It should also be noted that some embodiments may not necessarily include a waiting period for sending control messages and / or notifying the UE 102 of the transition to RRC idle mode. That is, in some cases, the eNB 104 may perform the sending and / or notification without a waiting period.

[0075] Figure 8Example control messages related to UE context and UE state according to some embodiments are shown. However, the embodiments are not limited thereto, and messages 800 and 850 may be or may be similar to "UE context retained / UE state change notification" and / or "UE context retained / UE state change notification response" messages that may be included in the 3GPP standard or other standards. It should be noted that some embodiments may include some, any or all of the parameters shown in the example messages 800 and 850, and some embodiments may also include additional parameters not shown in the example messages 800 and 850. In addition, the order and format shown in the example messages 800 and 850 are not restrictive, but are presented for illustrative purposes. Parameter values ​​may be given in any suitable format. As an example, some parameters may be Boolean values, taking values ​​such as yes / no or the like. As another example, some parameters may take values ​​of any appropriate number of digits or other numbers. As another example, some parameters may take descriptive values, which may be mapped to numbers in some cases.

[0076] The UE context is preserved / UE state change notification message 800 may be sent by the eNB 104 to the MME 122. The message 800 may include a UE state notification parameter 810, which may take values ​​such as "idle, context is stored" or "idle, context is suspended". The message 800 may include other parameters or information 820, which may or may not be related to the storage of the context or the RRC connection. For example, control information for the message 800 may be included.

[0077] UE context is preserved response / UE state change notification response message 850 may be sent by MME 122 to eNB 104. As a non-limiting example, message 850 may be sent in response to receiving message 800 at MME 122. Response message 850 may include UE state notification response parameter 860, which may take values ​​such as "accepted" or "failed" or the like. In some cases, these values ​​may be related to the state notification parameter 810 included in message 800. Message 850 may include other parameters or information 870, which may or may not be related to the storage of context or RRC connection. For example, control information for message 850 may be included.

[0078] Thus, message 800 may enable eNB 104 to notify MME 122 of the change in state of UE 102, which may enable downlink communication via paging. In some embodiments, message 800 may also enable eNB 104 to block, stop, or disable paging of UE 102 when UE 102 has connected back to the same eNB 104. When eNB 104 decides to store context information for UE 102, eNB 104 may send message 800, and message 800 may inform MME 122 that UE 102 is or will be in RRC idle or RRC connected mode. Message 800 may also serve as a request to MME 122 to notify S-GW 124 to preserve S1-U context and terminate S1 bearers upon notifying that UE 102 transitions to RRC idle mode.

[0079] In some embodiments, the eNB 104 may receive a response such as a UE Context Preserved / UE State Change Notification Response message 850 or other message. Such a message may inform the eNB 104 whether the MME 122 accepts the decision and / or request from the eNB 104 to maintain context information for the RRC connection for the UE 102. As an example, the MME 122 may reject the request and may include the reason and the reason in the message 850 or other message. As another example, when the UE 102 is in RRC idle mode, in response to the request or notification from the MME 122 to preserve the context information and suspend and / or maintain the S1-U bearer, the MME 122 may receive a rejection response from the S-GW 124. As another example, the MME 122 may wait for a response from the S-GW 124 before sending the message 850. As another example, the message 850 may be sent asynchronously. Reference Figure 7 , at operation 755 , message 850 or a similar message may be sent by the MME 122 to the eNB 104 .

[0080] Returning to method 500, at operation 540, the eNB 104 may receive a downlink data packet from the S-GW 124 for forwarding to the UE 102. At operation 545, the downlink data packet may be forwarded to the UE 102 over the RRC connection. In some embodiments, the forwarding may be based at least in part on the context information for the RRC connection that is retained. That is, when the UE 102 is in RRC idle mode, a packet may be received at the eNB 104 and may be forwarded based on the context for the UE 102 that is retained. In this case, one or more control messages that may otherwise be sent from the eNB 104 to the MME 122 and / or S-GW 124 (or in addition, between the MME 122 and the S-GW 124) may be avoided or may not need to be sent.

[0081] In some cases, the RRC connection release may be sent in response to receiving a packet from the S-GW 124 at the eNB 104. That is, in some cases, the previously described sending of the RRC connection release at operation 525 may be performed in response to operation 540 or after operation 540.

[0082] In an example scenario, the eNB 104 may support a large number of UEs 102 (e.g., UEs 102 configured to operate according to an MTC mode or protocol and / or other UEs 102). The eNB 104 may wish to refrain from sending RRC connection release messages for such a large number of UEs 102, some of which may frequently transition to an RRC idle mode. When a downlink packet arrives at the eNB 104 for forwarding to one of the UEs 102, the UE 102 may not have been notified of the RRC connection release and / or that context information is to be retained. Therefore, the eNB 104 may need to send an RRC connection release with an indication to the UE 102 that context information is to be retained.

[0083] In another example scenario, the eNB 104 may again support a large number of MTC-capable UEs 102 and / or other UEs 102. The eNB 104 may have flexibility in whether and / or when to send an RRC connection release message. Such a decision may be based on the number of UEs 102 supported by the eNB 104, the type of UE 102, the needs of the UE 102, or other factors.

[0084] At operation 550, the eNB 104 may receive a second uplink data packet from the UE 102 on the RRC connection based on the retained context information. That is, both the UE 102 and the eNB 104 may retain the context information, and the RRC connection may be reused for the second packet and possibly for other subsequent uplink data packets. As an example, the second uplink data packet may be received on the RRC connection after the RRC connection release message is sent, and the first uplink data packet may be received on the RRC connection before the RRC connection release message is sent.

[0085] In some embodiments, the eNB 104 may send a control message to the MME 122 instructing the UE 102 to transition from the RRC idle mode to the RRC connected mode for the RRC connection. As a non-limiting example, a "UE context is preserved / UE connection is terminated" control message may be used. As another non-limiting example, a "UE context release (existing) / UE state change notification (new)" control message may be used. However, these examples are not limiting, as other control messages or other messages may be used.

[0086] In some embodiments, the control message indicating the transition to the RRC connected mode may be sent in response to receiving an RRC connection request at the eNB 104. That is, the eNB 104 may determine that the UE 102 has transitioned from the RRC idle mode to the RRC connected mode based on the reception of an uplink packet to initiate a lightweight RRC connection establishment, which may be triggered by available uplink data or paging for downlink information.

[0087] At operation 555, the eNB 104 may send a second RRC connection release message for a second RRC connection between the eNB 104 and the second UE 102. In some embodiments, the second RRC connection release message may not include an indicator indicating the storage of the context information. As an example, the second UE 102 may be configured to operate in a non-MTC mode or a "normal" mode. In this case, the eNB 104 may send an RRC connection release indicating the storage of the context information for the MTC UE 102, and may send an RRC connection release that does not include such an indicator for the non-MTC UE 102. Therefore, in some embodiments, the eNB 104 may decide to maintain the context information for some UEs 102 and not maintain the context information for other UEs 102.

[0088] In some embodiments, the eNB 104 may exchange control messages with the MME 122 that may be related to the transition of the UE 102 from the RRC idle mode to the RRC connected mode. Although not limited to this, in some cases, the techniques and / or operations described herein for exchanging control messages for the transition of the UE 102 to the RRC idle mode may be used. As an example, the eNB 104 may delay sending such a control message to the MME 122 according to a waiting period. In some cases, the control message may be or may include an RRC connection release message or other message. For example, an indicator included in the RRC connection release message may indicate the transition of the UE 102 to the RRC idle mode or the RRC connected mode.

[0089] Fig. 9 5 shows the operation of another communication method according to some embodiments. Fig. 9 Embodiments of method 900 may include additional or even fewer operations or processes than those shown, and embodiments of method 900 are not necessarily limited to Fig. 9 When describing method 900, reference may be made to Figure 1-Figure 8 and Fig.11 , but it is understood that method 900 can be implemented with any other suitable systems, interfaces and components. In addition, the techniques and concepts described herein can be applied to method 900 in some cases, including RRC connection, RRC idle mode, RRC connection mode, RRC connection release, context information and / or others.

[0090] It should be noted that method 900 may be implemented at MME 122 and may include exchanging signals or messages with eNB 104. Similarly, method 500 may be implemented at eNB 104 and may include exchanging signals or messages with MME 122. In some cases, operations and / or techniques described as part of method 500 may be related to method 900. For example, operations of method 500 may include sending a message by eNB 104, while operations of method 900 may include receiving the same message or a similar message at MME 122.

[0091] At operation 905 of method 900, the MME 122 may receive a UE state change message from an eNB 104 configured to exchange data packets with the UE 102 over an RRC connection. In some embodiments, the message may indicate that the UE 102 transitions to an RRC idle mode for the RRC connection. As previously described, in some cases, the transition may occur due to the expiration of an inactivity timer at the eNB 104. The message may also indicate a request for the eNB 104 to maintain context information for the RRC connection. In some cases, the S-GW 124 may be configured to send a downlink data packet to the eNB 104 for forwarding to the UE 102 over the RRC connection. The UE state change message received at the MME 122 may also indicate that the eNB 104 implicitly requests the S-GW 124 to maintain a request for context information for the S1 bearer. As a non-limiting example, the UE state change message received at the MME 122 may be similar or identical to the UE context retained / UE state change notification message 800. Reference Figure 7 At operation 740, the eNB 104 may send a UE state change message to the MME 122.

[0092] At operation 910 of method 900, MME 122 may forward the UE state change message to S-GW 124. Thus, MME 122 may request S-GW 124 that context information should be retained for the S1 bearer or may query S-GW 124 whether context information can be retained. It should be noted that in some cases, the request may be made on behalf of eNB 104. As an example, a "UE state change notification and S1 reuse request" message described below may be used, but the embodiment is not limited to this message. In addition, Figure 7 Operation 740 may include sending the message or a similar message from the MME 122 to the S-GW 124 .

[0093] At operation 915, MME 122 may receive feedback related to the request from S-GW 124. Thus, the feedback may indicate whether context information can be retained for the S1 bearer. In some cases, the feedback may indicate a decision made by S-GW 124 on whether to support the retention of context information for the S1 bearer. As an example, the "S1 Reuse Response and UE Status Notification Response" message described below may be used, but the embodiment is not limited to this message. In addition, Figure 7 Operation 750 may include sending the message or a similar message from the S-GW 124 to the MME 122.

[0094] It should be noted that at operation 745, S-GW 124 may determine whether to preserve the S1-U bearer for the RRC connection of UE 102. This determination may be based at least in part on one or more indicators or other information included in the UE state change message sent from MME 122 to S-GW 124 at operation 910. The determination may also be based at least in part on the ability of S-GW 124 to preserve the context of UE 102 and / or other UEs 102. In some cases, S-GW 124 may determine whether the S1-U bearer is ready to be used. Such an example will be described below. Fig.11 Presented in.

[0095] At operation 920 of method 900, MME 122 may send a context preservation control message for the RRC connection to eNB 104. The message may indicate support for preserving context information for subsequent data packet exchanges on the RRC connection. In some embodiments, the decision on whether to support preserving context information may be based at least in part on capability information of UE 102 that may be received at MME 122 as part of establishment of the RRC connection. In some embodiments, the decision may be based at least in part on whether S-GW 124 supports preserving context information for S1 bearers or other aspects.

[0096] In some embodiments, the context preservation control message may be similar or identical to the UE context preserved / UE state change notification response message 850. Figure 7 At operation 755, a context preservation control message and / or message 850 may be sent by the MME 122 to the eNB 104. Thus, the context preservation control message may indicate whether the MME 122 accepts the request from the eNB 104 to preserve context information for the RRC connection. The context preservation control message may also indicate whether the S-GW 124 accepts the request to preserve context information for the S1 bearer. As a non-limiting example, the UE state change message received at the MME 122 may be similar or identical to the UE context preserved / UE state change notification message 800. Reference Figure 7 At operation 740 , a UE state change message may be sent by the eNB 104 to the MME 122 .

[0097] Fig.10Additional example control messages related to UE context and UE state according to some embodiments are shown. Although the embodiments are not limited thereto, messages 1000 and 1050 may be or may be similar to "UE state change notification and S1 reuse request" and / or "S1 reuse response and UE state notification response" messages that may be included in the 3GPP standard or other standards. It should be noted that some embodiments may include some, any or all of the parameters shown in the example messages 1000 and 1050, and some embodiments may also include additional parameters not shown in the example messages 1000 and 1050. In addition, the formats shown in the example messages 1000 and 1050 are not restrictive, but are presented for illustrative purposes. Parameter values ​​may be given in any suitable format. As an example, some parameters may be Boolean values, which take values ​​such as yes / no or the like. As another example, some parameters may take values ​​of any appropriate number of digits or other numbers. As another example, some parameters may take descriptive values, which may be mapped to numbers in some cases.

[0098] The UE state change notification and S1 reuse request message 1000 may be sent by the MME 122 to the S-GW 124. The message 1000 may include one or more UE state indicators 1010, which may take values ​​such as "UE state changed to idle" or "UE state changed to connected". The message 1000 may include other parameters or information 1020, which may or may not be related to the storage of contexts or the RCC connection. For example, control information for the message 1000 may be included.

[0099] The S1 reuse response and UE status notification response 1050 may be sent by the S-GW 124 to the MME 122. As a non-limiting example, the message 1050 may be sent in response to receiving the message 1000 at the S-GW 124. The response message 1050 may include a context storage indicator 1060, which may be related to the release of the S1 bearer and / or the retention of context information for the UE 102. As an example, the context storage indicator 1060 may indicate to the MME 122 that the S1 bearer will be released and / or the context information will not be retained. For example, if an S1 release is about to occur or if retaining the context information is not possible, the indicator 1060 may be set to a value of "1". The message 1050 may include other parameters or information 1070, which may or may not be related to the storage of the context or the RRC connection. For example, control information for the message 1050 may be included.

[0100] Fig.11Another example message flow diagram according to some embodiments is shown. Reference may be made to message flow diagram 1100 to illustrate messages, interfaces, and events that may be associated with some embodiments, but diagram 1100 is not limiting. Some embodiments may include operations that may be performed at UE 102, eNB 104, MME 122, and / or S-GW 124, but embodiments are not limited to these devices. In some embodiments, UE 102 may be a remote UE 102, but these embodiments are not limiting. In some cases, the techniques and concepts described herein may be applicable to Fig.11 The operations and / or events shown include RRC connection, RRC idle mode, RRC connected mode, RRC connection release, context information and / or others. Some embodiments may include Fig.11 One or more operations shown, and some embodiments may also include other operations described herein. In addition, the embodiments are not limited to Fig.11 The chronological order of operations is shown.

[0101] refer to Fig.11 , the exemplary message flow diagram 1100 may be applicable to the following situation: the remote UE 102 is in network coverage and in an idle state for the eNB 104, and can connect back to the eNB 104 by using a "lightweight" setup. The eNB 104 can store context information for the remote UE 102 and can act as a mobility anchor. As shown at 1115, the remote UE 102 can be in RRC idle mode. The access process 1130 can include the remote UE 102 sending an access request to the eNB 104, which access request can include a physical random access channel (PRACH) preamble and / or other messages. The access process 1130 can also include the eNB 104 sending an access response to the remote UE 102, which access response can include a random access response (RAR) and / or other messages. At operation 1132, the remote UE 102 can send a lightweight request to the eNB 104, which lightweight request can include information such as an identifier (UE ID) of the remote UE 102 and / or an establishment cause and / or other parameters or information. The lightweight request may be or may include a connection request from the remote UE 102. The message exchange, which may include operations 1135, 1140, 1150, 1155, and others, may be performed in response to the remote UE 102 sending the lightweight request and / or the eNB 104 receiving the lightweight request.

[0102] like Fig.11 As shown, any or all of operations 1135, 1140, 1150, and 1155 may be included in some embodiments. Such operations may be similar to those described with respect to Figure 7The operations of the example message flow diagram 700 in , but the embodiments are not limited thereto. The message exchange that may include operations 1135, 1140, 1150, 1155 and other operations may be performed in response to the remote UE 102 sending a lightweight request and / or receiving a lightweight request at the eNB 104.

[0103] It should be noted that at operation 1145, the S-GW 124 may determine whether an S1-U bearer for an RRC connection is prepared for the UE 102. In addition, the remote UE 102 may enter an ECM connected state as shown at 1160. At operation 1165, the eNB 104 may send a "Lightweight and Resource Allocation Response" message or other message and / or other information indicating that the remote UE 102 is connected to the remote UE 102.

[0104] It should be noted that if UE 102 has negotiated with the core network at the time of initial attach / connection setup, and MME 122 has agreed to support light connectivity (e.g., Fig.11 124) then the eNB 104 may not have to immediately notify the MME 122 and / or S-GW 124 when releasing the connection for the UE 102. Therefore, in some cases, a saving in signaling may be achieved, such as when the UE 102 does not receive downlink data. It should also be noted that in some embodiments, the above negotiation (for enabling the MME 122 to support light connection) may be extended to determine or decide the duration for which the MME 122 and / or S-GW 124 supports storage of the S1-U bearer context. As an example, a timer may be used to achieve this purpose.

[0105] In Example 1, an apparatus for an evolved Node B (eNB) may include a hardware processing circuit and a transceiver circuit. The hardware processing circuit may configure the transceiver circuit to receive an uplink data packet from a user equipment (UE) over a radio resource control (RRC) connection between the eNB and the UE. The hardware processing circuit may also configure the transceiver circuit to send an RRC connection release message to the UE to indicate a transition of the UE to an RRC idle mode for the RRC. The RRC connection release message may include an indicator indicating whether the UE stores context information for the RRC connection.

[0106] In Example 2, the subject matter of Example 1, wherein the indicator indicating whether the UE stores the context information may be based at least in part on whether the UE is configured for machine type communication (MTC) or Internet of Things (IoT) operation.

[0107] In Example 3, the subject matter of one or any combination of Examples 1-2, wherein the RRC Connection Release message may be sent in response to expiration of an inactivity timer of the UE at the eNB.

[0108] In Example 4, the subject matter of one or any combination of Examples 1-3, wherein the context information may include an identifier of a data radio bearer (DRB) included in the RRC connection and an indicator of a security key for the RRC connection.

[0109] In Example 5, the subject matter of one or any combination of Examples 1-4, wherein the RRC connection release message may also indicate termination of DRBs included in the RRC connection.

[0110] In Example 6, the subject matter of one or any combination of Examples 1-5, when the RRC connection release message indicates that the UE is to store the context information for the RRC connection, the hardware processing circuit may be configured to retain the context information for the RRC connection.

[0111] In Example 7, the subject matter of one or any combination of Examples 1-6, the hardware processing circuitry may further configure the transceiver circuitry to forward the downlink data packet to the UE over the RRC connection, the forwarding may be based at least in part on the retained context information.

[0112] In Example 8, the subject matter of one or any combination of Examples 1-7, wherein the hardware processing circuitry may further configure the transceiver circuitry to send an indicator to a mobility management entity (MME) indicating that the RRC connection is a lightweight RRC connection, wherein for the lightweight RRC connection, the eNB is allowed to delay notifying the MME of a release of the lightweight RRC connection. The hardware processing circuitry may further configure the transceiver circuitry to receive a second uplink data packet from the UE on the lightweight RRC connection based on the retained context information.

[0113] In Example 9, the subject matter of one or any combination of Examples 1-8, wherein an indicator indicating that the RRC connection is a lightweight RRC connection may be included in the "UE context preserved / UE connection terminated" RRC control message.

[0114] In Example 10, the subject matter of one or any combination of Examples 1-9, wherein the hardware processing circuitry may further configure the transceiver circuitry to send a control message to the MME indicating a transition of the UE from an RRC idle mode to an RRC connected mode for an RRC connection for a forwarding serving gateway (S-GW). The control message may be sent in response to receiving a connection request message from the UE.

[0115] In Example 11, the subject matter of one or any combination of Examples 1-10, the hardware processing circuit may further configure the transceiver circuit to receive a second uplink data packet from the UE on the RRC connection based on the retained context information.

[0116] In Example 12, the subject of one or any combination of Examples 1-11, the second uplink data packet may be received after the RRC connection release message is sent. The uplink data packet may be received before the RRC connection release message is sent.

[0117] In Example 13, the subject matter of one or any combination of Examples 1-12, wherein the hardware processing circuitry may further configure the transceiver circuitry to exchange one or more setup control messages for the RRC connection with a mobility management entity (MME). The hardware processing circuitry may further configure the transceiver circuitry to restrict sending a control message to the MME for a transition of the UE to an RRC idle mode for the RRC connection.

[0118] In Example 14, the subject matter of one or any combination of Examples 1-13, wherein the limiting of transmission may be performed during the waiting period, and the hardware processing circuitry may further configure the transceiver circuitry to transmit the control message after the waiting period.

[0119] In Example 15, the subject matter of one or any combination of Examples 1-14, wherein the hardware processing circuitry may further configure the transceiver circuitry to exchange one or more setup control messages for the RRC connection with a mobility management entity (MME). The hardware processing circuitry may further configure the transceiver circuitry to send a control message to the MME indicating a transition of the UE from the RRC idle mode to the RRC connected mode.

[0120] In Example 16, the subject matter of one or any combination of Examples 1-15, wherein the hardware processing circuitry further configures the transceiver circuitry to exchange one or more setup control messages for the RRC connection with a mobility management entity (MME). The hardware processing circuitry may also configure the transceiver circuitry to send a control message to the MME indicating a transition of the UE from an RRC idle mode to an RRC connected mode for the RRC connection.

[0121] In Example 17, the subject matter of one or any combination of Examples 1-16, wherein the hardware processing circuitry may further configure the transceiver circuitry to send a second RRC connection release message for a second RRC connection between the eNB and the second UE. The second RRC connection release message may not include an indicator for storing context information for the second RRC connection. The UE may be configured for machine type communication (MTC) operation, and the second UE may be configured for non-MTC operation.

[0122] In Example 18, the subject matter of one or any combination of Examples 1-17, wherein the apparatus may include one or more antennas coupled to the transceiver circuitry for receiving uplink data packets and transmitting the RRC connection release message.

[0123] In Example 19, a non-transitory computer-readable storage medium may store instructions for execution by one or more processors to perform operations for an evolved Node B (eNB) to communicate. The operations may configure the one or more processors to send an RRC connection release message indicating that the eNB and a user equipment (UE) will retain context information for a radio resource control (RRC) connection between the eNB and the UE. The operations may also configure the one or more processors to receive an uplink data packet from the UE on the RRC connection based on the retained context information.

[0124] In Example 20, the subject matter of Example 19, wherein the RRC connection release message may also indicate a transition of the UE to an RRC idle mode for the RRC connection.

[0125] In Example 21, the subject matter of one or any combination of Examples 19-20, wherein the uplink data packet may be received after the RRC connection release message is sent.

[0126] In Example 22, the subject matter of one or any combination of Examples 19-21, wherein the RRC Connection Release message may be sent in response to expiration of an inactivity timer of the UE at the eNB.

[0127] In Example 23, an apparatus for a mobility management entity (MME) may include a hardware processing circuit and a transceiver circuit. The hardware processing circuit may configure the transceiver circuit to receive a UE state change message from an evolved Node B configured to exchange data packets with a user equipment (UE) on a radio resource control (RRC) connection, the UE state change message indicating a transition of the UE to an RRC idle mode for the RRC connection. The hardware processing circuit may also configure the transceiver circuit to send a context retention control message for retaining context information for the RRC connection by the eNB and the UE for subsequent exchange of data packets on the RRC connection.

[0128] In Example 24, the subject matter of Example 23, wherein the UE state change message may indicate a request to persist context information for the RRC connection. The context preservation control message may indicate an acceptance response of the MME to the request to persist the context information.

[0129] In Example 25, the subject matter of one or any combination of Examples 23-24, wherein the hardware processing circuitry may further configure the transceiver circuitry to forward the UE state change message to a serving gateway (S-GW). The S-GW may be configured to send a downlink data packet to the eNB to forward to the UE over the RRC connection. Acceptance of the request to retain the context information may be based on feedback from the S-GW.

[0130] In Example 26, the subject matter of one or any combination of Examples 23-25, wherein acceptance of the request to retain the context information may be based at least in part on capability information of the UE received at the MME as part of establishment of the RRC connection.

[0131] In Example 27, the subject matter of one or any combination of Examples 23-26, wherein acceptance of the request to persist the context information may be based at least in part on whether the UE is configured for machine type communication (MTC) operation or Internet of Things (IoT) operation.

[0132] The Abstract is provided to comply with 37 CFR Section 1.72(b)'s requirement for an abstract that allows the reader to ascertain the nature and gist of the technical disclosure. The Abstract is submitted with the understanding that it will not be used to limit or interpret the scope or meaning of the claims. Thus, the following claims are incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.

Claims

1. An apparatus of an evolved Node B (eNB) configured for cellular Internet of Things (IoT) operation, the apparatus comprising: Memory; and A processing circuit, the processing circuit is used to: Obtaining capability information of user equipment UE; Determining, based on the capability information, that the UE connected to the eNB is configured to operate according to a machine type communication (MTC) protocol; In response to determining that the UE is configured to operate according to the MTC protocol, configuring the eNB to initiate a radio resource control RRC connection termination procedure for the IoT user equipment UE, the RRC connection termination procedure comprising: Encode a first control message for indicating termination of the RRC connection of the UE and termination of the context of the UE, so as to transmit the message to a mobility management entity MME through an S1 interface; Sending the first control message to the MME; decoding a second control message confirming the first control message based on signaling received from the MME over the S1 interface; In response to receiving the second control message, encode an RRCConnectionRelease message for suspending the RRC connection of the UE for transmission to the UE, the RRCConnectionRelease message comprising one or more indicators, the one or more indicators being used to notify the UE to suspend the RRC connection and store an access stratum AS context, wherein during the suspension of the RRC connection, one or more suspended data radio bearers DRB remain established and inactive, and wherein the memory is configured to store the one or more indicators; and Send the RRCConnectionRelease message to the UE.

2. The device according to claim 1, wherein: The second control message includes security context information.

3. The device according to claim 2, wherein: The security context information includes a security key for the RRC connection of the UE.

4. The device according to claim 1, wherein: The one or more indicators indicate a cause of the RRCConnectionRelease message.

5. The device according to any one of claims 1 to 4, wherein: The one or more indicators indicate a cause including termination of the RRC connection.

6. A device for an Internet of Things (IoT) user equipment UE, the device comprising: Memory; and A processing circuit, the processing circuit is used to: Providing capability information of the UE; In response to an indication that the UE is operating according to a machine type communication (MTC) protocol, configuring the UE to perform a radio resource control (RRC) connection termination procedure, the RRC connection termination procedure comprising: decoding an RRCConnectionRelease message according to signaling received from an evolved Node B (eNB) to terminate the RRC connection of the UE, the RRCConnectionRelease message comprising one or more indicators for notifying the UE to terminate the RRC connection and store an access stratum (AS) security context, wherein during the termination of the RRC connection, one or more terminated data radio bearers (DRBs) remain established and inactive; In response to receiving the RRCConnectionRelease message, storing at least the AS context in the memory; In response to receiving the RRCConnectionRelease message, terminating a data radio bearer DRB for the RRC connection; and In response to receiving the RRCConnectionRelease message, entering the RRC idle mode.

7. The device according to claim 6, wherein: The one or more indicators indicate a cause of the RRCConnectionRelease message.

8. The device according to claim 6 or 7, wherein: The one or more indicators indicate a cause including termination of the RRC connection.

9. A method for a cellular Internet of Things (IoT), comprising: Obtaining capability information of user equipment UE; determining, based on the capability information, that the UE connected to an evolved Node B (eNB) is configured to operate according to a machine type communication (MTC) protocol; as well as The eNB is configured to initiate a radio resource control (RRC) connection termination procedure for an IoT user equipment (UE), wherein the RRC connection termination procedure includes: In response to determining that the UE is configured to operate according to the MTC protocol, encoding a first control message for indicating termination of the RRC connection of the UE and termination of the context of the UE for transmission to a mobility management entity MME through an S1 interface; Sending the first control message to the MME; decoding a second control message confirming the first control message based on signaling received from the MME over the S1 interface; In response to receiving the second control message, encode an RRCConnectionRelease message for suspending the RRC connection of the UE for transmission to the UE, the RRCConnectionRelease message comprising one or more indicators, the one or more indicators being used to notify the UE to suspend the RRC connection and store an access stratum AS context, wherein during the suspension of the RRC connection, one or more suspended data radio bearers DRB remain established and inactive; and Send the RRCConnectionRelease message to the UE.

10. The method according to claim 9, wherein: The second control message includes security context information.

11. The method according to claim 10, wherein: The security context information includes a security key for the RRC connection of the UE.

12. The method according to claim 9, wherein: The one or more indicators indicate a cause of the RRCConnectionRelease message.

13. The method according to any one of claims 9 to 12, wherein: The one or more indicators indicate a cause including termination of the RRC connection.

14. A method for a cellular Internet of Things (IoT), comprising: Providing capability information of user equipment UE; In response to an indication that the UE is operating according to a machine type communication (MTC) protocol, configuring the UE to perform a radio resource control (RRC) connection termination procedure, the RRC connection termination procedure comprising: decoding an RRCConnectionRelease message according to signaling received from an evolved Node B (eNB) to terminate the RRC connection of the UE, the RRCConnectionRelease message comprising one or more indicators for notifying the UE to terminate the RRC connection and store an access stratum (AS) security context, wherein during the termination of the RRC connection, one or more terminated data radio bearers (DRBs) remain established and inactive; In response to receiving the RRCConnectionRelease message, storing at least the AS context in the memory; In response to receiving the RRCConnectionRelease message, terminating a data radio bearer DRB for the RRC connection; and In response to receiving the RRCConnectionRelease message, entering the RRC idle mode.

15. The method according to claim 14, wherein: The one or more indicators indicate a cause of the RRCConnectionRelease message.

16. The method according to claim 14 or 15, wherein: The one or more indicators indicate a cause including termination of the RRC connection.

17. A system for cellular Internet of Things (IoT), configured to implement the method according to any one of claims 9 to 16.

18. A computer-readable storage medium, configured to implement the method according to any one of claims 9 to 16.

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