Maintaining ue link adaptation configuration during intra-cell handover

Abstract

A method of operating a network node includes establishing a first connection to a UE in a cell of the network node and performing link adaptation of the first connection. In connection with performing link adaptation of the first connection, the network node stores a value associated with at least one state variable that is used for performing link adaptation of the first connection, and in response to an intra-cell handover of the UE from the first connection in the cell to a second connection in the cell, the network node applies the value associated with the at least one state variable to link adaptation of the second connection. Related network nodes are also disclosed.

Description

[0001] MAINTAINING UE LINK ADAPTATION CONFIGURATION DURING INTRACELL HANDOVER

[0002] TECHNICAL FIELD

[0003] The present application relates to wireless communication networks, and in particular to wireless communication networks that support intra-cell handover.

[0004] BACKGROUND

[0005] The 5th generation (5G) wireless New Radio (NR) standard has been widely implemented. It is well known that 5G is designed for higher transmission speeds, greater reliability, and increased access. With the rapid increase in the number of 5G users, NR system performance and efficiency have become more and more important.

[0006] Figure 1 illustrates a simplified communication system including a base station 100 and a user equipment (UE) 200. The base station 100 transmits downlink (DL) communications to the UE 200 and receives uplink (UL) communications from the UE 200. The communication system may be a Long Term Evolution (LTE) or a NR network, but may include other types of communication networks, such as other network types compliant with 3rd Generation Partnership Project (3GPP) specifications.

[0007] As shown in Figure 1, the base station 100 transmits data to the UE 200 as well as reference signals and control information, such as resource assignments (RA) and modulation and coding scheme (MCS) indicators to enable the UE 200 to decode DL signals. The UE 200 transmits control information, such as channel quality indicator (CQI) reports to the base station 100 to provide feedback indicative of the quality of the DL channel.

[0008] The base station 100 performs various functions, including DL link adaptation and DL scheduling. In particular, the DL scheduler in the base station 100 determines DL resource assignments for the UE 100. The DL link adaptation function adjusts the MCS used for DL communications based on feedback provided by the UE 200, as described below.

[0009] Link adaptation is used in 4G and 5G mobile communications networks to select a suitable MCS to be applied to DL communications to the UE. Several criteria may be used to guide the selection of an MCS. For example, a criterion could be to maximize cell throughput and / or to achieve a given block error rate (BLER). To select an appropriate MCS in the downlink, link adaptation relies on measurements provided by the UE, namely CQIs. The base station uses the reported CQIs to assign an appropriate MCS to each user.

[0010] The feedback loop of CQI reporting / MCS selection is referred to as “inner loop” link adaptation, and is illustrated as loop 110 in Figure 2. As shown therein, the CQI reports are provided by the UE 200 to the base station 100. The base station 100 adapts the MCS used for downlink transmissions based on the CQI in an inner feedback loop 110. In practice, CQI reports may provide inaccurate or biased information. This may be due to delays in CQI reporting, missing CQI reports and other reasons. These CQI inaccuracies may affect the performance of link adaptation, which in turn results in suboptimal use of radio resources.

[0011] To correct for these inaccuracies, the base station 100 also implements an “outer loop” link adaptation strategy. The base station 100 receives acknowledgments that are submitted by a UE after every transmission, referred to as Hybrid Automatic Repeat reQuest (HARQ) feedback, illustrated in Figure 2 as HARQ feedback 120. For example, a HARQ ACK (ACK for short) is reported when a transmission is correctly decoded, and a HARQ NACK (NACK for short) is reported if the UE was not able to decode the transmission. These HARQ acknowledgments are used by an outer loop in link adaptation to compensate for inaccuracies in the CQI reports. This strategy is known as outer loop link adaptation (OLLA), because it occurs on a slower time frame compared to inner loop link adaptation. OLLA allows the system to adapt to long-term channel variations, promoting efficient data transmission and increasing overall system capacity.

[0012] OLLA is usually implemented as a controller that corrects the current SINR estimate. That is, the controller computes a compensated SINR that is equal to the current SINR estimate minus an outer loop adjustment. The controller for outer loop link adaptation is commonly designed to adjust the estimate of the SINR so that an estimate of the BLER based on the HARQ acknowledgments matches a given BLER target.

[0013] Figure 3 shows a block diagram of a communication system 10 that implements OLLA. The base station 100 may be part of a Radio Access Network (RAN) (not pictured) that is in communication with a Core Network (CN) (not pictured) and may be, for example, an eNodeB or gNodeB, which may be in communication with a core network in an LTE or NR network. The base station 100 provides the air interface for the UEs 200 and communicatively couples the UEs to a CN, for example. The base station 100 includes an outer-loop adjustment function module 16 for controlling adaptation of the wireless communication link between the base station 100 and the UEs 200.

[0014] The outer-loop adjustment function module 16 may be implemented, for example, in hardware on a processor 18 or as a combination of hardware and software. Programmatic code to implement aspects of the outer-loop adjustment function module 16, including the functions of the processor 18 can be stored in a memory 20. The outerloop adjustment function module 16 may utilize a communication interface 22 to determine characteristics of the communication link, such as the channel quality between the base station 100 and the UEs 200 The communication interface 22 may also be used for data communication between the base station 100 and the UE 200.

[0015] Figure 4 illustrates a conventional method by a outer-loop adjustment function module 16 of a base station 100 for adjusting the MCS applied to DL communications with a UE using OLLA. Initially, such as when a UE 200 first becomes connected to a base station 100, an outer loop adjustment value OL_Adj that is associated to the UE is set at 0 (block 402). When the base station 100 receives transport block (TB) transmission feedback (e.g., HARQ feedback) from the UE (block 404), the base station determines based on the feedback whether transmission of the TB was successful or not.

[0016] If transmission of the TB was successful, the outer-loop adjustment function module 16 adjusts the OL Adj value upwards by adding an upward adjustment (up step) to the value of OL Adj for the UE (block 408). Likewise, if transmission of the TB was unsuccessful, the outer-loop adjustment function module 16 adjusts the OL Adj value downwards by subtracting a downward adjustment (down step) from the value of OL Adj for the UE (block 410).

[0017] A conventional algorithm for measuring channel quality uses fixed upward and downward step sizes for outer-loop adjustment for all the modulation modes. For example, the upward step size (up_step) may be calculated based on a target block error rate (BLER) and the downward step size (down step). In some approaches, the step sizes may be adjustable.

[0018] The outer-loop adjustment function module 16 adjusts a channel quality measure by the outer-loop adjustment value (block 412). For example, the outer-loop adjustment value may be added to the channel quality measure to obtain an adjusted channel quality measure.

[0019] The base station 100 then adjusts the MCS applied to DL transmissions to the UE based on the adjusted channel quality measure (block 414). Operations then return to block 404 upon receipt of the next TB transmission feedback from the UE.

[0020] SUMMARY

[0021] A method of operating a network node according to some embodiments includes establishing a first connection to a UE in a cell of the network node, and performing link adaptation of the first connection. In connection with performing link adaptation of the first connection, the network node stores a value associated with at least one state variable that is used for performing link adaptation of the first connection, and in response to an intra-cell handover of the UE from the first connection in the cell to a second connection in the cell, the network node applies the value associated with the at least one state variable to link adaptation of the second connection.

[0022] Performing link adaptation may include performing inner loop link adaptation and outer loop link adaptation. Performing inner loop link adaptation may include receiving channel state information, CSI, from the UE and adjusting a modulation and coding scheme, MCS, used for communications with the UE in response to the channel state information, and wherein performing outer loop link adaptation includes receiving hybrid automatic repeat request, HARQ, feedback from the UE and adjusting the MCS used for communications with the UE in response to the HARQ feedback.

[0023] The state variable may include one or more of: an outer loop link adaptation, OLA, value, a channel quality indicator, CQI, value, a rank indicator, RI, value, and a precoding matrix indicator, PMI, value.

[0024] The value associated with the at least one state variable may be the at least one state variable. In some embodiments, the value associated with the at least one state variable may be a value derived from the at least one state variable, he value derived from the at least one state variable may include a mean value of the at least one state variable, a median value of the at least one state variable or a filtered value of the at least one state variable. The method may further include storing the state variable in a storage unit in connection with performing link adaptation of the first connection, and in response to the intra-cell handover, retrieving the state variable from the storage unit.

[0025] The method may further include storing a UE identifier together with the state variable, wherein retrieving the state variable includes retrieving the state variable based on the UE identifier.

[0026] In some embodiments, link adaptation of the first connection may be performed by a baseband unit in the network node.

[0027] The UE identifier and the at least one state variable may be stored in the storage unit by a processing unit in the network node.

[0028] The processing unit may inform the baseband unit that the UE will perform the intra-cell handover, and the baseband unit may retrieve the at least one state variable from the storage unit based on the UE identifier in response to the UE establishing the second connection in connection with the intra-cell handover.

[0029] The network node may include a control unit, CU, and a distributed unit, DU, wherein the baseband unit is part of the DU.

[0030] The baseband unit may be informed of the intra-cell handover of the UE by a higher protocol layer within the network node.

[0031] The method may further include storing a time value associated with the value associated with at least one state variable. The validity of the value associated with at least one state variable may be determined based on the time value. The method may further include re-calculating the value associated with at least one state variable based on the time value. Re-calculating the value associated with at least one state variable may be performed when a time represented by the time value has passed.

[0032] The connection to the network node may include a connection to a baseband unit of the network node. The connection to the network node includes a radio resource control, RRC, connection to the base station.

[0033] An apparatus for performing link adaptation of a connection according to some embodiments includes a processor and a memory. The memory contains instructions executable by the processor whereby the apparatus is operative to establish a first connection to a user equipment, UE, in a cell of the network node, perform link adaptation of the first connection, in connection with performing link adaptation of the first connection, store a value associated with at least one state variable that is used for performing link adaptation of the first connection, and in response to an intra-cell handover of the UE from the first connection in the cell to a second connection in the cell, apply the value associated with the at least one state variable to link adaptation of the second connection.

[0034] An apparatus according to some embodiments is adapted to establish a first connection to a user equipment, UE, in a cell of the network node, perform link adaptation of the first connection, in connection with performing link adaptation of the first connection, store a value associated with at least one state variable that is used for performing link adaptation of the first connection, and in response to an intra-cell handover of the UE from the first connection in the cell to a second connection in the cell, apply the value associated with the at least one state variable to link adaptation of the second connection.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 illustrates a simplified communication system including a base station and a user equipment.

[0037] Figure 2 illustrates a feedback loop of CQI reporting / MCS selection.

[0038] Figure 3 shows a block diagram of a communication system that implements outer loop link adaptation.

[0039] Figure 4 illustrates a conventional method by an outer-loop adjustment function module of a base station for adjusting the MCS applied to downlink communications with a UE using outer loop link adaptation.

[0040] Figure 5 illustrates the value of the outer loop adjustment state variable associated with a UE before and after an intra-cell handover.

[0041] Figures 6A and 6B illustrate network nodes according to some embodiments that may store and re-use baseband configurations of a UE after an intra-cell handover.

[0042] Figure 7 illustrates operations of a network node according to some embodiments.

[0043] Figure 8 shows an example of a communication system in accordance with some embodiments.

[0044] Figure 9 shows a UE in accordance with some embodiments.

[0045] Figure 10 shows a network node in accordance with some embodiments. Figure 11 is a block diagram of a host in accordance with various aspects described herein.

[0046] Figure 12 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized.

[0047] Figure 13 shows a communication diagram of a host communicating via a network node with a UE over a partially wireless connection in accordance with some embodiments.

[0048] DETAILED DESCRIPTION OF EMBODIMENTS

[0049] As discussed above, link adaptation (LA) algorithms are designed to meet an average block error rate (BLER) target. LA algorithms in a base station exploit a control loop to adjust the signal to interference plus noise (SINR) estimate recovered from CQI, and hence the modulation and coding scheme (MCS), in an attempt to meet a long-term BLER target.

[0050] Link adaptation may be applied to both the physical downlink shared channel (PDSCH) and the physical uplink shared channel (PUSCH), and consists of an inner loop MCS selector that targets a fixed Block Error Rate (BLER) of 10% for all HARQ transmissions and an outer loop channel quality corrector based on HARQ ACK / NACK feedback to enforce the BLER target.

[0051] For the PDSCH, channel state information (CSI) reported by UE (including CQI, and a rank indicator, RI) is commonly used as channel quality input for link adaptation.

[0052] For the PUSCH, received SINR is measured in the base station and used as the channel quality input for link adaptation.

[0053] There currently exist certain challenges regarding link adaptation. In many cases, the outer loop adjustment may not be optimal for end user performance. For example, when a UE that is connected using dual connectivity (DC) performs an intra-cell handover (HO), the UE may hand over to the same NR cell due to a change in the Master eNB (MeNB), synchronization between gNB and UE, or some other reason. From the point of view of the base station, configurations used by the UE, which may have been processed for a long time such that the outer loop has converged according to BLER target, will be erased, requiring the outer loop compensation process to start over again. In practice, it is likely that after an intra-cell HO, the UE is in the same physical location as it was before the HO and would therefore experience similar radio conditions relative to the base station. Thus, the configurations of Channel State Information (CSI) such as channel quality indicator (CQI), rank indicator (RI), precoding matrix indicator (PMI), as well as link adaptation values, such as the outer loop adjustment value (OLA), before the handover may still be valid for the UE after the intra-cell HO occurs.

[0054] When the LA process is restarted, the state variables used for LA are reset to default values. After such reset, it takes a finite amount of time for the values of the state variables to converge again. Before the LA process converges, the UE may experience undesired levels of BLER or reduced throughput due to overly conservative selections of MCS. Some embodiments described herein are based on a recognition that it may be possible to improve both the UL and DL network performance by decreasing or eliminating this convergence period after an intra-cell HO.

[0055] Figure 5 is a graph that illustrates the value of the OLA state variable associated with a UE before and after an intra-cell HO. In particular, Figure 5(a) illustrates the physical cell identity (PCI) of the cell to which the UE is connected to, Figure 5(b) illustrates the Cell-Radio Network Temporary Identifier (C-RNTI) used by the UE to access the cell, and Figure 5(c) illustrates the value of the OLA state variable used for the connection before and after a handover occurs at time t = 0. As can be seen in Figure 5, after the HO, the PCI stays the same (indicating 1 that the UE stays connected to the same cell), but the UE accesses the cell with a different C-RNTI, indicating that an intra-cell HO has occurred at time t = 0, and the UE now has a different logical connection to the cell.

[0056] It can be observed that before the HO, the OLA value had converged to about -3. However, after the HO, the OLA value is reset to 0 (the default value) and then gradually adjusts downward and converges at the previous level. During the adjustment period, the performance of the link may be degraded. Similar behavior could occur for other state variables associated with the UE that are used for LA or other functions, such as CQI, RI, PMI, etc.

[0057] According to some embodiments, a base station (in some embodiments a distributed unit, DU, of a gNB in a NR system) stores values related to state variables associated with each UE that is connected to a cell of the base station. The state variables may, for example, represent a baseband configuration associated with a UE. In particular, the state variables may include baseband configurations of CSI and LA for each UE, such as CQI, RI, PMI, OLA, etc. A value that is stored may be the latest or most recently used value of the state variable itself, or a value derived from the value of the state variable, such as a mean or median of a state variable, or a filtered version of the state variable (e.g., the average of the last n samples of the state variable).

[0058] Once a UE is recognized as performing intra-cell HO, the baseband configurations of the UE are stored in a storage unit, such as a memory or buffer, along with a unique identity (ID) of the UE which is used as an index. After the UE is detected to have accessed the cell again within a predetermined time period, the base station retrieves the baseband configuration from the storage unit. Then, instead of treating the UE as a brand new entrant to the cell (with a default baseband configuration), the stored baseband configuration is applied to the link adaptation loop for the UE.

[0059] Accordingly, the value of state variables that are immediately applied to the LA loop when the UE re-connects to the cell may be more representative of the radio condition of the UE, and may therefore take less time to converge than would be needed if the initial or default values were used.

[0060] If there is no stored baseband configuration with a matching ID when a UE access the cell, the LA process for the UE would start with initial values and eventually converge to stable values.

[0061] Some embodiments allow a gNB to store baseband configurations for LA for UEs that can be used after an intra-cell HO of the UE. This may which shorten the convergence time for link adaptation, which may increase efficiency and improve system performance.

[0062] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0063] Figure 6A illustrates a network node 600 according to some embodiments that may store and re-use baseband configurations of a UE after an intra-cell HO. In particular, the network node 600 may be a DU of a gNB in a NR radio access network (RAN). The network node 600 includes a baseband unit 620 that handles baseband processing of communication signals transmitted to and received from a UE 605, a storage unit 624 that stores baseband configurations for use after intra-cell handover, and a processing unit 622 that manages the storage, retrieval and use of baseband configurations by the network node 600.

[0064] When the UE 605 performs an initial access to a cell controlled by the network node, the UE 605 connects to the network node 600 via the baseband unit 620 with a first connection 625 A including an uplink connection (UL) and a downlink connection (DL). In particular, the connection 625A may be a radio resource control (RRC) connection to the network node 600.

[0065] The baseband unit 620 manages the LA process with the UE 605. To support LA, the baseband unit 620 uses a baseband configuration 610 associated with the connection 625 A to the UE 605. The baseband configuration may include CSI received from the UE 605, such as CQI, RI and PMI, as well as state variables related to the first connection 625A, such as an OLA. The values in the baseband configuration 610 are generally referred to as state variables (SV), and are associated with the UE 605 and the connection 625A.

[0066] The baseband unit 620 may optionally store an identifier (ID) of the UE in association with the state variables SV. The ID may be provided by higher protocol layers within the network node 600, such as the RRC layer and higher. The baseband configuration 610 may be stored in a UE information unit 615A that is established to support the connection 625A.

[0067] The baseband unit 620 may transmit the state variables SV and the ID to the processing unit 622, which may store the state variables SV and ID in the storage unit 624. In some embodiments, the baseband unit 620 may only transmit the state variables SV to the processing unit 622, and the processing unit 622 may determine the ID of the UE 605 to which the state variables SV are associated.

[0068] The processing unit 622 may store values SV‘ associated with the state variables SV in the storage unit 624 in a record 630 along with the ID of the UE 605. The values SV‘ associated with the state variables SV that are stored in the storage unit 624 may be the values of the state variables SV themselves, or may be values derived from the state variables SV, such as mean or median of the state variables, or filtered versions of the state variable (e.g., the average of the last n samples of the state variable).

[0069] In some embodiments, the baseband unit may generate the values SV’ from the state variables SV and transmit the values SV’ to the processing unit 622.

[0070] The processing unit 622 may store a time value TV associated with the state variables SV. For example, the time value TV may be a timestamp indicative of a time when the state variables SV were recorded or stored or last modified. In some embodiments, the time value TV may be a time interval (e.g., number of milliseconds) during which the state variables are valid or usable. For example, after the expiration of such time interval, it may be assumed that the state variables SV are no longer accurate and should not be used as initial state variables after an intra-cell handover. In some embodiments, the validity of the state variable SV or the value SV may be determined based on the time value. The state variable SV or the value SV may be re-calculated based on the time value, such as when a time represented by the time value has passed (e.g., when more than a predetermined number of seconds have passed since the timestamp, or when the time interval has expired, etc.)

[0071] The SV associated with the state variables SV may be periodically stored in the storage unit 624, or may be stored by the processing unit 622 in response to determining that the UE 605 will perform an intra-cell handover, or in response to an indication by higher protocol layers to store the values SV’.

[0072] Following an intra-cell handover 635, the UE 605 becomes connected to the cell operated by the network node 600 via a second connection 625B with the baseband unit 620. The processing unit 622 checks the ID of the UE 605 that establishes the second connection 625B and determines that a record 630 corresponding to the UE 605 is stored in the storage unit 624. The processing unit 622 transmits the values SV’ to the baseband unit 620, which stores the values SV’ in a UE information unit 615B and uses the values SV’ as state variables for the second connection 625B rather than using default values of state variables for the second connection 625B.

[0073] Figure 6B illustrates a network node 600 according to some embodiments that may store and re-use baseband configurations of a UE after an intra-cell HO. In particular, the network node 600 includes a control unit (CU) 640 and one or more distributed units (DU) 650A, 650B. Each DU 650A, 650B implements functionality of a baseband unit that handles baseband processing of communication signals transmitted to and received from a UE 605. The CU 640 includes a storage unit 644 that stores configurations for use after intra-cell handover, and a processing unit 642 that manages the storage, retrieval and use of baseband configurations by the network node 600.

[0074] When the UE 605 performs an initial access to a cell controlled by the network node, the UE 605 connects to the network node 600 via the DU 650A with a first connection 625A, such as an RRC connection, including an uplink connection (UL) and a downlink connection (DL).

[0075] The DU 650A manages the LA process with the UE 605. To support LA, the DU 650A uses a baseband configuration 610 associated with the connection 625 A to the UE 605. The baseband configuration may include CSI received from the UE 605, such as CQI, RI and PMI, as well as state variables related to the first connection 625A, such as an OLA.

[0076] The DU 650A 620 may optionally store an identifier (ID) of the UE in association with the state variables SV. The baseband configuration 610 may be stored in a UE information unit 615A that is established to support the connection 625A.

[0077] The DU 650A may transmit the state variables SV and the ID to the CU 640, which may store the state variables SV and ID in the storage unit 644. In some embodiments, the DU 650A may only transmit the state variables SV to the CU 640, and the CU 640 may determine the ID of the UE 605 to which the state variables SV are associated.

[0078] The CU 640 may store values SV‘ associated with the state variables SV in the storage unit 644 in a record 630 along with the ID of the UE 605. The values SV‘ associated with the state variables SV that are stored in the storage unit 624 may be the values of the state variables SV themselves, or may be values derived from the state variables SV, such as mean or median of the state variables, or filtered versions of the state variable (e.g., the average of the last n samples of the state variable).

[0079] In some embodiments, the DU 650A may generate the values SV’ from the state variables SV and transmit the values SV’ to the CU 640.

[0080] The CU 640 may store a time value TV associated with the state variables SV. For example, the time value TV may be a timestamp indicative of a time when the state variables SV were recorded or stored or last modified. In some embodiments, the time value TV may be a time interval (e.g., number of milliseconds) during which the state variables are valid or usable. For example, after the expiration of such time interval, it may be assumed that the state variables SV are no longer accurate and should not be used as initial state variables after an intra-cell handover.

[0081] The SV‘ associated with the state variables SV may be periodically stored in the storage unit 644, or may be stored by the processing unit 642 in response to determining that the UE 605 will perform an intra-cell handover, or in response to an indication by higher protocol layers to store the values SV’.

[0082] Following an intra-cell handover 630, the UE 605 becomes connected to the cell operated by the network node 600 via a second connection 625B with the DU 650B. The CU 640 checks the ID of the UE 605 that establishes the second connection 625B and determines that a record 630 corresponding to the UE 605 is stored in the storage unit 624. The CU 640 transmits the values SV’ to the DU 650B, which uses the values SV’ as state variables for the second connection 625B rather than using default values of state variables for the second connection 625B.

[0083] Figure 7 illustrates operations of a network node according to some embodiments.

[0084] Referring to Figure 7, a method of operating a network node includes establishing a first connection to a UE in a cell of the network node (block 702). The network node performs link adaptation of the first connection (block 704). In connection with performing link adaptation of the first connection, the network node stores a value associated with at least one state variable that is used for performing link adaptation of the first connection.

[0085] The network node detects an intra-cell handover of the UE from the first connection in the cell to a second connection in the cell (block 708). In response to the intra-cell handover of the UE, the network node may optionally store the value associated with the at least one state variable (block 708). The network node applies the value associated with the at least one state variable to link adaptation of the second connection (block 710).

[0086] Performing link adaptation includes performing inner loop link adaptation and outer loop link adaptation, wherein performing inner loop link adaptation includes receiving channel state information, CSI, from the UE and adjusting a modulation and coding scheme, MCS, used for communications with the UE in response to the channel state information, and performing outer loop link adaptation includes receiving hybrid automatic repeat request, HARQ, feedback from the UE and adjusting the MCS used for communications with the UE in response to the HARQ feedback.

[0087] The state variable may include one or more of: an outer loop link adaptation, OLA, value, a channel quality indicator, CQI, value, a rank indicator, RI, value, and a precoding matrix indicator, PMI, value. The value associated with the at least one state variable may be the at least one state variable.

[0088] The value associated with the at least one state variable may be a value that is derived from the at least one state variable. For example, the value derived from the at least one state variable may be a mean value of the at least one state variable, a median value of the at least one state variable or a fdtered value of the at least one state variable.

[0089] The method may further include storing the state variable in a storage unit in connection with performing link adaptation of the first connection, and in response to the intra-cell handover, retrieving the state variable from the storage unit.

[0090] The method may further include storing a UE identifier together with the state variable, wherein retrieving the state variable includes retrieving the state variable based on the UE identifier.

[0091] The link adaptation of the first connection may be performed by a baseband unit in the network node.

[0092] The UE identifier and the at least one state variable may be stored in the storage unit by a processing unit in the network node.

[0093] The processing unit may inform the baseband unit that the UE will perform the intra-cell handover, and the baseband unit may retrieve the at least one state variable from the storage unit based on the UE identifier in response to the UE establishing the second connection in connection with the intra-cell handover.

[0094] The network node may include a control unit, CU, and a distributed unit, DU. The baseband unit may be part of the DU. The baseband unit may be informed of the intra-cell handover of the UE by a higher protocol layer within the network node.

[0095] Figure 8 shows an example of a communication system 800 in accordance with some embodiments.

[0096] In the example, the communication system 800 includes a telecommunication network 802 that includes an access network 804, such as a radio access network (RAN), and a core network 806, which includes one or more core network nodes 808. The access network 804 includes one or more access network nodes, such as network nodes 810a and 810b (one or more of which may be generally referred to as network nodes 810), or any other similar 3rdGeneration Partnership Project (3GPP) access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunication network 802 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network 802 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network 802, including one or more network nodes 810 and / or core network nodes 808.

[0097] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU-CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an O-2 interface defined by the O-RAN Alliance or comparable technologies. The network nodes 810 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 812a, 812b, 812c, and 812d (one or more of which may be generally referred to as UEs 812) to the core network 806 over one or more wireless connections.

[0098] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 800 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 800 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0099] The UEs 812 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 810 and other communication devices. Similarly, the network nodes 810 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 812 and / or with other network nodes or equipment in the telecommunication network 802 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 802.

[0100] In the depicted example, the core network 806 connects the network nodes 810 to one or more hosts, such as host 816. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 806 includes one more core network nodes (e.g., core network node 808) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 808. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0101] The host 816 may be under the ownership or control of a service provider other than an operator or provider of the access network 804 and / or the telecommunication network 802, and may be operated by the service provider or on behalf of the service provider. The host 816 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0102] As a whole, the communication system 800 of Figure 8 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Uong Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0103] In some examples, the telecommunication network 802 is a cellular network that implements 3 GPP standardized features. Accordingly, the telecommunications network 802 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 802. For example, the telecommunications network 802 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC)ZMassive loT services to yet further UEs.

[0104] In some examples, the UEs 812 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 804 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 804. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0105] In the example, the hub 814 communicates with the access network 804 to facilitate indirect communication between one or more UEs (e.g., UE 812c and / or 812d) and network nodes (e.g., network node 810b). In some examples, the hub 814 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 814 may be a broadband router enabling access to the core network 806 for the UEs. As another example, the hub 814 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 810, or by executable code, script, process, or other instructions in the hub 814. As another example, the hub 814 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 814 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 814 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 814 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 814 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0106] The hub 814 may have a constant / persistent or intermittent connection to the network node 810b. The hub 814 may also allow for a different communication scheme and / or schedule between the hub 814 and UEs (e.g., UE 812c and / or 812d), and between the hub 814 and the core network 806. In other examples, the hub 814 is connected to the core network 806 and / or one or more UEs via a wired connection. Moreover, the hub 814 may be configured to connect to an M2M service provider over the access network 804 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 810 while still connected via the hub 814 via a wired or wireless connection. In some embodiments, the hub 814 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 810b. In other embodiments, the hub 814 may be a nondedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 810b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0107] Figure 9 shows a UE 900 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0108] A UE may support device -to-de vice (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0109] The UE 900 includes processing circuitry 902 that is operatively coupled via a bus 904 to an input / output interface 906, a power source 908, a memory 910, a communication interface 912, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 9. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0110] The processing circuitry 902 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 910. The processing circuitry 902 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 902 may include multiple central processing units (CPUs).

[0111] In the example, the input / output interface 906 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 900. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0112] In some embodiments, the power source 908 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 908 may further include power circuitry for delivering power from the power source 908 itself, and / or an external power source, to the various parts of the UE 900 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 908. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 908 to make the power suitable for the respective components of the UE 900 to which power is supplied.

[0113] The memory 910 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 910 includes one or more application programs 914, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 916. The memory 910 may store, for use by the UE 900, any of a variety of various operating systems or combinations of operating systems.

[0114] The memory 910 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini -dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 910 may allow the UE 900 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 910, which may be or comprise a device-readable storage medium.

[0115] The processing circuitry 902 may be configured to communicate with an access network or other network using the communication interface 912. The communication interface 912 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 922. The communication interface 912 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 918 and / or a receiver 920 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 918 and receiver 920 may be coupled to one or more antennas (e.g., antenna 922) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0116] In the illustrated embodiment, communication functions of the communication interface 912 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / intemet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0117] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 912, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0118] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0119] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 900 shown in Figure 9.

[0120] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0121] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0122] Figure 10 shows a network node 1000 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)), O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU).

[0123] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units, distributed units (e.g., in an O-RAN access node) and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0124] Other examples of network nodes include multiple transmission point (multi- TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi- cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0125] The network node 1000 includes a processing circuitry 1002, a memory 1004, a communication interface 1006, and a power source 1008. The network node 1000 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 1000 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 1000 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1004 for different RATs) and some components may be reused (e.g., a same antenna 1010 may be shared by different RATs). The network node 1000 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1000, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1000.

[0126] The processing circuitry 1002 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 1000 components, such as the memory 1004, to provide network node 1000 functionality.

[0127] In some embodiments, the processing circuitry 1002 includes a system on a chip (SOC). In some embodiments, the processing circuitry 1002 includes one or more of radio frequency (RF) transceiver circuitry 1012 and baseband processing circuitry 1014. In some embodiments, the radio frequency (RF) transceiver circuitry 1012 and the baseband processing circuitry 1014 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 1012 and baseband processing circuitry 1014 may be on the same chip or set of chips, boards, or units.

[0128] The memory 1004 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device- readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 1002. The memory 1004 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 1002 and utilized by the network node 1000. The memory 1004 may be used to store any calculations made by the processing circuitry 1002 and / or any data received via the communication interface 1006. In some embodiments, the processing circuitry 1002 and memory 1004 is integrated.

[0129] The communication interface 1006 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 1006 comprises port(s) / terminal(s) 1016 to send and receive data, for example to and from a network over a wired connection. The communication interface 1006 also includes radio front-end circuitry 1018 that may be coupled to, or in certain embodiments a part of, the antenna 1010. Radio front-end circuitry 1018 comprises fdters 1020 and amplifiers 1022. The radio front-end circuitry 1018 may be connected to an antenna 1010 and processing circuitry 1002. The radio front-end circuitry may be configured to condition signals communicated between antenna 1010 and processing circuitry 1002. The radio front-end circuitry 1018 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio frontend circuitry 1018 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1020 and / or amplifiers 1022. The radio signal may then be transmitted via the antenna 1010. Similarly, when receiving data, the antenna 1010 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1018. The digital data may be passed to the processing circuitry 1002. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0130] In certain alternative embodiments, the network node 1000 does not include separate radio front-end circuitry 1018, instead, the processing circuitry 1002 includes radio front-end circuitry and is connected to the antenna 1010. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1012 is part of the communication interface 1006. In still other embodiments, the communication interface 1006 includes one or more ports or terminals 1016, the radio front-end circuitry 1018, and the RF transceiver circuitry 1012, as part of a radio unit (not shown), and the communication interface 1006 communicates with the baseband processing circuitry 1014, which is part of a digital unit (not shown).

[0131] The antenna 1010 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 1010 may be coupled to the radio front-end circuitry 1018 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1010 is separate from the network node 1000 and connectable to the network node 1000 through an interface or port.

[0132] The antenna 1010, communication interface 1006, and / or the processing circuitry 1002 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 1010, the communication interface 1006, and / or the processing circuitry 1002 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0133] The power source 1008 provides power to the various components of network node 1000 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1008 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1000 with power for performing the functionality described herein. For example, the network node 1000 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 1008. As a further example, the power source 1008 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0134] Embodiments of the network node 1000 may include additional components beyond those shown in Figure 10 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 1000 may include user interface equipment to allow input of information into the network node 1000 and to allow output of information from the network node 1000. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1000.

[0135] Figure 11 is a block diagram of a host 1100, which may be an embodiment of the host 816 of Figure 8, in accordance with various aspects described herein. As used herein, the host 1100 may be or comprise various combinations hardware and / or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host 1100 may provide one or more services to one or more UEs.

[0136] The host 1100 includes processing circuitry 1102 that is operatively coupled via a bus 1104 to an input / output interface 1106, a network interface 1108, a power source 1110, and a memory 1112. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 9 and 10, such that the descriptions thereof are generally applicable to the corresponding components of host 1100.

[0137] The memory 1112 may include one or more computer programs including one or more host application programs 1114 and data 1116, which may include user data, e.g., data generated by a UE for the host 1100 or data generated by the host 1100 for a UE. Embodiments of the host 1100 may utilize only a subset or all of the components shown. The host application programs 1114 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FLAC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems). The host application programs 1114 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 1100 may select and / or indicate a different host for over-the-top services for a UE. The host application programs 1114 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.

[0138] Figure 12 is a block diagram illustrating a virtualization environment 1200 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1200 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 1200 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an 0-2 interface.

[0139] Applications 1202 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0140] Hardware 1204 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1206 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1208a and 1208b (one or more of which may be generally referred to as VMs 1208), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 1206 may present a virtual operating platform that appears like networking hardware to the VMs 1208.

[0141] The VMs 1208 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1206. Different embodiments of the instance of a virtual appliance 1202 may be implemented on one or more of VMs 1208, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment. In the context of NFV, a VM 1208 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, nonvirtualized machine. Each of the VMs 1208, and that part of hardware 1204 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1208 on top of the hardware 1204 and corresponds to the application 1202.

[0142] Hardware 1204 may be implemented in a standalone network node with generic or specific components. Hardware 1204 may implement some functions via virtualization. Alternatively, hardware 1204 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1210, which, among others, oversees lifecycle management of applications 1202. In some embodiments, hardware 1204 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1212 which may alternatively be used for communication between hardware nodes and radio units.

[0143] Figure 13 shows a communication diagram of a host 1302 communicating via a network node 1304 with a UE 1306 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as a UE 812a of Figure 8 and / or UE 900 of Figure 9), network node (such as network node 810a of Figure 8 and / or network node 1000 of Figure 10), and host (such as host 816 of Figure 8 and / or host 1100 of Figure 11) discussed in the preceding paragraphs will now be described with reference to Figure 13.

[0144] Like host 1100, embodiments of host 1302 include hardware, such as a communication interface, processing circuitry, and memory. The host 1302 also includes software, which is stored in or accessible by the host 1302 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE 1306 connecting via an over-the-top (OTT) connection 1350 extending between the UE 1306 and host 1302. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection 1350.

[0145] The network node 1304 includes hardware enabling it to communicate with the host 1302 and UE 1306. The connection 1360 may be direct or pass through a core network (like core network 806 of Figure 8) and / or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.

[0146] The UE 1306 includes hardware and software, which is stored in or accessible by UE 1306 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via UE 1306 with the support of the host 1302. In the host 1302, an executing host application may communicate with the executing client application via the OTT connection 1350 terminating at the UE 1306 and host 1302. In providing the service to the user, the UE's client application may receive request data from the host's host application and provide user data in response to the request data. The OTT connection 1350 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through the OTT connection 1350.

[0147] The OTT connection 1350 may extend via a connection 1360 between the host 1302 and the network node 1304 and via a wireless connection 1370 between the network node 1304 and the UE 1306 to provide the connection between the host 1302 and the UE 1306. The connection 1360 and wireless connection 1370, over which the OTT connection 1350 may be provided, have been drawn abstractly to illustrate the communication between the host 1302 and the UE 1306 via the network node 1304, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

[0148] As an example of transmitting data via the OTT connection 1350, in step 1308, the host 1302 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE 1306. In other embodiments, the user data is associated with a UE 1306 that shares data with the host 1302 without explicit human interaction. In step 1310, the host 1302 initiates a transmission carrying the user data towards the UE 1306. The host 1302 may initiate the transmission responsive to a request transmitted by the UE 1306. The request may be caused by human interaction with the UE 1306 or by operation of the client application executing on the UE 1306. The transmission may pass via the network node 1304, in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step 1312, the network node 1304 transmits to the UE 1306 the user data that was carried in the transmission that the host 1302 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1314, the UE 1306 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 1306 associated with the host application executed by the host 1302.

[0149] In some examples, the UE 1306 executes a client application which provides user data to the host 1302. The user data may be provided in reaction or response to the data received from the host 1302. Accordingly, in step 1316, the UE 1306 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input / output interface of the UE 1306. Regardless of the specific manner in which the user data was provided, the UE 1306 initiates, in step 1318, transmission of the user data towards the host 1302 via the network node 1304. In step 1320, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 1304 receives user data from the UE 1306 and initiates transmission of the received user data towards the host 1302. In step 1322, the host 1302 receives the user data carried in the transmission initiated by the UE 1306.

[0150] One or more of the various embodiments improve the performance of OTT services provided to the UE 1306 using the OTT connection 1350, in which the wireless connection 1370 forms the last segment. More precisely, the teachings of these embodiments may improve the throughput performance of UE’s following intra-cell handover and thereby provide benefits such as improved responsiveness and throughput.

[0151] In an example scenario, factory status information may be collected and analyzed by the host 1302. As another example, the host 1302 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host 1302 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host 1302 may store surveillance video uploaded by a UE. As another example, the host 1302 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs. As other examples, the host 1302 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing and / or transmitting data.

[0152] In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1350 between the host 1302 and UE 1306, in response to variations in the measurement results. The measurement procedure and / or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of the host 1302 and / or UE 1306. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 1350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1350 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of the network node 1304. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency and the like, by the host 1302. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 1350 while monitoring propagation times, errors, etc.

[0153] Referring to Figures 6A, 6B, 7 and 10, some embodiments provide a network node (600, 1000) including processing circuitry (1002) and power supply circuitry (1008) configured to supply power to the processing circuitry. The network node is configured to perform operations comprising establishing (702) a first connection to a user equipment, UE, in a cell of the network node; performing (704) link adaptation of the first connection; in connection with performing link adaptation of the first connection, storing (708) a value associated with at least one state variable that is used for performing link adaptation of the first connection; and in response to an intra-cell handover of the UE from the first connection in the cell to a second connection in the cell, applying (710) the value associated with the at least one state variable to link adaptation of the second connection.

[0154] A network node (600) according to some embodiments includes a baseband unit (620) configured to establish (702) a first connection to a UE in a cell of the network node and to perform (704) link adaptation of the first connection; a storage unit (624) configured to store (708) a value associated with at least one state variable that is used for performing link adaptation of the first connection; and a processing unit (622) configured to detect an intra-cell handover of the UE from the first connection in the cell to a second connection in the cell, and in response to detecting the intra-cell handover, to retrieve the value associated with the at least one state variable and provide the value to the baseband unit.

[0155] The baseband unit may be configured to apply (710) the value associated with the at least one state variable to link adaptation of the second connection.

[0156] The network node may perform link adaptation by performing inner loop link adaptation and outer loop link adaptation. Performing inner loop link adaptation may include receiving CSI from the UE and adjusting a MCS used for communications with the UE in response to the channel state information. Performing outer loop link adaptation may include receiving HARQ feedback from the UE and adjusting the MCS used for communications with the UE in response to the HARQ feedback.

[0157] The state variable may include one or more of: an OLA value, a CQI value, a RI value, and a PMI value.

[0158] The value associated with the at least one state variable may be the at least one state variable.

[0159] The value associated with the at least one state variable may be a value derived from the at least one state variable.

[0160] The value derived from the at least one state variable may be a mean value of the at least one state variable, a median value of the at least one state variable or a filtered value of the at least one state variable.

[0161] The network node may store the state variable in a storage unit in connection with performing link adaptation of the first connection; and in response to the intra-cell handover, retrieve the state variable from the storage unit. The network node may store a UE identifier together with the state variable and retrieve the state variable based on the UE identifier.

[0162] The network node may perform link adaptation of the first connection in a baseband unit in the network node.

[0163] The UE identifier and the at least one state variable may be stored in the storage unit by a processing unit in the network node.

[0164] The processing unit may inform the baseband unit that the UE will perform the intra-cell handover, and the baseband unit may retrieve the at least one state identifier variable from the storage unit based on the UE identifier in response to the UE establishing the second connection in connection with the intra-cell handover.

[0165] The network node may include a CU and a DU. The baseband unit may be part of the DU.

[0166] The baseband unit may be informed of the intra-cell handover of the UE by a higher protocol layer within the network node.

[0167] The network node may store a time value associated with the value associated with at least one state variable and retrieves the state variable based on based on the time value.

[0168] The connection to the network node may include a connection to a baseband unit of the network node.

[0169] The connection to the network node may be a RRC connection to the base station.

[0170] A network node (600, 1000) according to some embodiments includes a distributed unit (650A, 650B) configured to establish (702) a first connection to a UE in a cell of the network node and to perform (704) link adaptation of the first connection; and a control unit (640) including a storage unit (644) and a processing unit (642). The control unit is configured to store (708) a value associated with at least one state variable that is used for performing link adaptation of the first connection and to detect an intra- cell handover of the UE from the first connection in the cell to a second connection in the cell, and in response to detecting the intra-cell handover, to retrieve the value associated with the at least one state variable and provide the value to the baseband unit.

[0171] Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non- computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0172] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer-readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

Claims

Claims1. A method of operating a network node, the method comprising: establishing (702) a first connection to a user equipment, UE, in a cell of the network node; performing (704) link adaptation of the first connection; in connection with performing link adaptation of the first connection, storing (708) a value associated with at least one state variable that is used for performing link adaptation of the first connection; and in response to an intra-cell handover of the UE from the first connection in the cell to a second connection in the cell, applying (710) the value associated with the at least one state variable to link adaptation of the second connection.

2. The method of Claim 1, wherein performing link adaptation comprises performing inner loop link adaptation and outer loop link adaptation, wherein performing inner loop link adaptation comprises receiving channel state information, CSI, from the UE and adjusting a modulation and coding scheme, MCS, used for communications with the UE in response to the channel state information, and wherein performing outer loop link adaptation comprises receiving hybrid automatic repeat request, HARQ, feedback from the UE and adjusting the MCS used for communications with the UE in response to the HARQ feedback.

3. The method of Claim 2, wherein the state variable comprises one or more of: an outer loop link adaptation, OLA, value, a channel quality indicator, CQI, value, a rank indicator, RI, value, and a precoding matrix indicator, PMI, value.

4. The method of any previous Claim, wherein the value associated with the at least one state variable comprises the at least one state variable.

5. The method of any of Claims 1 to 3, wherein the value associated with the at least one state variable comprises a value derived from the at least one state variable.

6. The method of Claim 5, wherein the value derived from the at least one statevariable comprises a mean value of the at least one state variable, a median value of the at least one state variable or a filtered value of the at least one state variable.

7. The method of any previous Claim, further comprising: storing the state variable in a storage unit in connection with performing link adaptation of the first connection; and in response to the intra-cell handover, retrieving the state variable from the storage unit.

8. The method of Claim 7, further comprising: storing a UE identifier together with the state variable, wherein retrieving the state variable comprises retrieving the state variable based on the UE identifier.

9. The method of Claim 7 or 8, wherein link adaptation of the first connection is performed by a baseband unit in the network node.

10. The method of Claim 9, wherein the UE identifier and the at least one state variable are stored in the storage unit by a processing unit in the network node.

11. The method of Claim 10, wherein the processing unit informs the baseband unit that the UE will perform the intra-cell handover, and wherein the baseband unit retrieves the at least one state variable from the storage unit based on the UE identifier in response to the UE establishing the second connection in connection with the intra-cell handover.

12. The method of Claim 9, wherein the network node comprises a control unit, CU, and a distributed unit, DU, wherein the baseband unit is part of the DU.

13. The method of Claim 9, wherein the baseband unit is informed of the intra-cell handover of the UE by a higher protocol layer within the network node.

14. The method of any previous Claim, further comprising: storing a time value associated with the value associated with at least one state variable;wherein validity of the value associated with at least one state variable is determined based on the time value.

15. The method of Claim 14, further comprising re-calculating the value associated with at least one state variable based on the time value.

16. The method of Claim 15, wherein re-calculating the value associated with at least one state variable is performed when a time represented by the time value has passed.

17. The method of any of Claims 1 to 16, wherein the connection to the network node comprises a connection to a baseband unit of the network node.

18. The method of any of Claims 1 to 17, wherein the connection to the network node comprises a radio resource control, RRC, connection to the base station.

19. An apparatus for performing link adaptation of a connection, comprising a processor and a memory, the memory containing instructions executable by the processor whereby the apparatus is operative to: establish (702) a first connection to a user equipment, UE, in a cell of the network node; perform (704) link adaptation of the first connection; in connection with performing link adaptation of the first connection, store (708) a value associated with at least one state variable that is used for performing link adaptation of the first connection; and in response to an intra-cell handover of the UE from the first connection in the cell to a second connection in the cell, apply (710) the value associated with the at least one state variable to link adaptation of the second connection.

20. The apparatus of Claim 19, wherein the apparatus is operative to perform operations according to any of Claims 2 to 18.

21. An apparatus adapted to: establish (702) a first connection to a user equipment, UE, in a cell of the networknode; perform (704) link adaptation of the first connection; in connection with performing link adaptation of the first connection, store (708) a value associated with at least one state variable that is used for performing link adaptation of the first connection; and in response to an intra-cell handover of the UE from the first connection in the cell to a second connection in the cell, apply (710) the value associated with the at least one state variable to link adaptation of the second connection.

22. The apparatus of Claim 21, wherein the apparatus is adapted to perform operations according to any of Claims 2 to 18.

Images