Random access by bandwidth switching

Abstract

To provide improved random access operations from which various communication systems may benefit.SOLUTION: Certain embodiments may benefit from improved random access in which multiple bandwidth parts are configured to user equipment within one cell. A method, in certain embodiments, may include triggering a random access procedure at user equipment. The method may also include switching at the user equipment from a first uplink bandwidth part that does not support a random access channel to a second uplink bandwidth part that has the random access channel configured after the triggering of the random access procedure. The switching may be autonomously performed by the user equipment. In addition, the method may include performing the random access procedure at the user equipment using the random access channel configured at the second uplink bandwidth part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] Various communication systems may benefit from improved random access operation. For example, certain embodiments may benefit from improved random access where multiple bandwidth portions are configured to user equipment in a cell. [Background technology]

[0002] In Third Generation Partnership Project (3GPP) technologies such as Long Term Evolution (LTE) and LTE-A, a user equipment (UE) can start accessing network services once the UE is synchronized with the network. A random access procedure is typically used to synchronize the UE with the network in the uplink direction via a physical random access channel (PRACH). The random access procedure may be a contention-based random access procedure or a non-contention / contention-free random access procedure.

[0003] When multiple UEs attempt to access the network at the same time, a contention-based random access procedure can be used. The contention-based random access procedure can be used to resolve potential collisions between multiple UEs and also to synchronize the UE with the network. This contention-based random access procedure can include four separate messages transmitted between the UE and the network. The UE first sends a first message having a random access channel preamble including a random access radio network temporary identifier (RA-RNTI). The network entity then decodes the received RA-RNTI and responds by sending a random access response in a second message. The random access response typically includes a temporary cell-radio network temporary identifier (C-RNTI), a timing advance value, and an uplink grant resource.

[0004] The UE uses its timing advance value to synchronize with the network and sends a Radio Resource Control (RRC) connection request in a third message using the temporary C-RNTI. The UE also includes a random value or a Temporary Mobile Subscriber Identity (TMSI) in the third message, which can be used by the network to determine a new C-RNTI if the temporary C-RNTI has been assigned to multiple UEs. The network entity can then respond with a Contention Resolution message or an RRC Connection Setup message that includes the new C-RNTI. The new C-RNTI is used by both the UE and the network entity to exchange data with each other while the UE remains in the Connected RRC state.

[0005] The system bandwidth of a given cell, used by network entities and UEs for both downlink and uplink transmissions, may be divided into one or more bandwidth portions. For paired spectrum, a downlink bandwidth portion and an uplink bandwidth portion (BWP) are configured separately and respectively for each serving cell UE. Paired spectrum is characterized by a block of spectrum in a lower frequency band associated with a block of spectrum in an upper frequency band using Frequency Division Duplexing (FDD). On the other hand, for unpaired spectrum utilizing Time Division Duplexing (TDD), the downlink BWP and uplink BWP are configured jointly as a pair but share the same center frequency.

[0006] In the primary cell, for example, a random access channel can be configured in each uplink BWP, and each downlink BWP must have a common search space (CSS) for random access response. If some BWPs of the primary cell are not configured with a RACH, at least the initial BWP supports a random access channel. In 3GPP 5G or New Radio (NR) technology, the number of scheduling requests can be counted. When the number of scheduling requests is equal to or greater than the scheduling request transmission maximum value, the user equipment can initiate a random access procedure similar to LTE or LTE-A. Summary of the Invention

[0007] According to a particular embodiment, the device may include at least one memory including computer program code and at least one processor. The at least one memory and the computer program code may be configured by the at least one processor to cause the device to at least trigger a random access procedure in the user equipment. The at least one memory and the computer program code may also be configured by the at least one processor to cause the device to at least switch from a first uplink bandwidth portion not supporting a random access channel to a second uplink bandwidth portion in which the random access channel is configured after triggering of the random access procedure. The switching may be performed autonomously by the device. Additionally, the at least one memory and the computer program code may be configured by the at least one processor to cause the device to at least perform a random access procedure with a random access channel configured in the second uplink bandwidth portion.

[0008] A method of certain embodiments may include triggering a random access procedure at a user equipment. The method may also include switching at the user equipment from a first uplink bandwidth portion that does not support a random access channel to a second uplink bandwidth portion in which the random access channel is configured after triggering of the random access procedure. The switching may be performed autonomously by the user equipment. In addition, the method may include performing at the user equipment the random access procedure using the random access channel configured in the second uplink bandwidth portion.

[0009] An apparatus of a particular embodiment may include means including means for triggering a random access procedure at the user equipment. The apparatus also includes means for switching at the user equipment from a first uplink bandwidth portion that does not support a random access channel to a second uplink bandwidth portion in which the random access channel is configured after triggering the random access procedure. The switching may be performed autonomously by the user equipment. Additionally, the apparatus may include means for performing, at the user equipment, the random access procedure using the random access channel configured in the second uplink bandwidth portion.

[0010] According to certain embodiments, the apparatus may include a non-transitory computer-readable medium encoded with instructions that, when executed in hardware, perform a process. The process may include triggering a random access procedure at the user equipment. The process may also include switching at the user equipment from a first uplink bandwidth portion that does not support a random access channel to a second uplink bandwidth portion in which the random access channel is configured after triggering the random access procedure. The switching may be performed autonomously by the user equipment. Additionally, the process may include performing, at the user equipment, a random access procedure with a random access channel configured in the second uplink bandwidth portion.

[0011] According to certain other embodiments, a computer program product may be coded with instructions for performing a process. The process may include triggering a random access procedure at the user equipment. The process may also include switching at the user equipment from a first uplink bandwidth portion that does not support a random access channel to a second uplink bandwidth portion in which the random access channel is configured after triggering of the random access procedure. The switching may be performed autonomously by the user equipment. Additionally, the process may include performing at the user equipment a random access procedure using a random access channel configured in the second uplink bandwidth portion.

[0012] For a proper understanding of the present invention, reference should be made to the accompanying drawings. [Brief description of the drawings]

[0013] [Figure 1] 1 illustrates an example of a flowchart in accordance with certain embodiments. [Diagram 2] 1 illustrates an example of a system in accordance with certain embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Certain embodiments may include beam failure detection. When a beam failure is detected, the UE may send a beam recovery request. A beam recovery request may be triggered or initiated when the number of consecutive detected beam failure instances exceeds a given threshold. The threshold may be defined, for example, as a block error rate (BLER). Some embodiments may have one or more thresholds. In a multiple threshold embodiment, for example, one threshold may be for a synchronization signal block (SSB), while the other threshold may be for a channel state information reference signal (CSI-RS). In NR technology, a network entity, for example, a 5G or NR NodeB (gNB), may uniquely identify a user equipment from a beam failure recovery request using a PRACH sequence provided by the network to the UE.

[0015] To determine the dedicated PRACH resource for beam failure recovery, certain parameters related to the UE may be configured. For example, preamble sequence related parameters, such as root sequence, cyclic shift and / or preamble index, may be set. In another example, the maximum number of transmissions, the maximum number of power rampings, the target received power, the retransmission power ramping step size and / or the beam failure recovery timer of the UE may be configured. In some embodiments, dedicated PRACH resource parameters may also be configured, such as frequency location information, time location and / or associated SSB or CSI-RS information. Once the beam failure trigger is met, the UE may transmit a dedicated PRACH preamble to recover the link via a random access procedure.

[0016] In some embodiments, only a subset of the total uplink bandwidth portion may support a random access procedure via the PRACH, also referred to below as the random access channel (RACH). Thus, the UE may be restricted to performing a random access procedure towards a primary cell (PCell) or a primary secondary cell (PSCell) only in the subset of the uplink bandwidth portion. Certain embodiments may enable a UE in RRC connected mode to handle UE-based triggering of a random access procedure when the network is not aware of such an event. In other words, the UE may be able to autonomously trigger a random access procedure even if the current active BWP, which may be referred to as the first uplink BWP, does not support a random access channel.

[0017] For example, when a random access procedure is triggered by the UE and the currently active BWP does not support a random access channel, certain embodiments allow the UE to autonomously switch to another uplink BWP, which may be referred to as a second uplink BWP in which the random access channel is configured. The UE performing the switch autonomously may mean that the switch can be performed without any knowledge or involvement from the network. Since the currently active BWP does not support and / or is not configured for RACH, the network may not be aware that the UE is attempting to initiate a random access procedure. The first uplink BWP and the second uplink BWP may be different.

[0018] FIG. 1 illustrates an example of a flow chart according to a particular embodiment. In particular, FIG. 1 illustrates an example of a user equipment performing a method or process. In step 110, the UE may trigger a random access procedure. The random access procedure may be triggered via a RACH. The UE may be in an RRC connected state during the triggering of the random access procedure. As shown in step 150, the UE may switch from a first uplink BWP that does not support a random access channel to a second uplink BWP in which a random access channel is configured. In other words, the second uplink BWP may already have a configured RACH.

[0019] In certain embodiments where multiple uplink BWPs support the random access channel, a network entity, such as a gNB, can determine in which uplink BWP the UE should initiate the random access channel. Multiple BWPs may be configured in the UE in a single cell. The network entity may be included in, for example, a PCell or a PSCell. The network entity can transmit the uplink BWP decision as part of a configuration instruction to the UE. As shown in step 120, the UE can receive a configuration instruction from the network entity. Based on the configured instruction, the UE can select a second uplink BWP from the multiple BWPs, as shown in step 130. In some other embodiments, the UE can receive configuration information from the network entity prior to the triggering of the random access procedure in step 110, as shown in step 120.

[0020] In other embodiments, the alternative or second uplink bandwidth portion may be determined by the UE without configuration directed from a network entity as shown in step 140. For example, the second uplink bandwidth portion may be determined by the UE based on at least one of the numerology and / or the frequency of the random access channel. The numerology may be a subcarrier spacing. NR technology supports multiple numerology options associated with multiple subcarrier spacings. The subcarrier spacing may be, for example, 15, 30, 60, 120, and 240 kilohertz (kHz). The UE may determine the second BWP based on any of the multiple numerology options and / or the frequency utilized by the BWP. In some embodiments, the UE may be configured with at least a default BWP from the multiple BWPs. The UE may determine the second BWP based on whether it is the default BWP.

[0021] As described above, in step 140, the user equipment selects a second uplink BWP. In some embodiments, the second BWP can be selected based on the UE implementation and / or may be selected based on a default and / or initial BWP. The default and / or initial BWP can be configured for other purposes, such as energy saving, and can be used as a fallback for the RACH. Selection based on the UE implementation can mean that it is up to the UE implementation to select the BWP of the cell configuring the RACH. In yet another embodiment, the UE can select the second BWP based on the logical channel that triggers the random access procedure or the priority of the logical channel. For example, some logical channels can be restricted to be mapped to uplink channels with a particular subcarrier spacing, and thus a BWP with a RACH supporting the particular subcarrier spacing to which the logical channel is restricted can be preferred.

[0022] Once the second BWP portion is selected, the user equipment may switch from the first uplink bandwidth portion that does not support a random access channel, as shown in step 140, to the second uplink bandwidth portion in which a random access channel is configured, as shown in step 150. The switch from the first uplink bandwidth portion to the second uplink bandwidth portion may be performed autonomously by the user equipment. In some embodiments, the network may not even be aware that the UE is performing a random access procedure. The switch illustrated in step 150 may include the UE autonomously deactivating the first uplink BWP and activating the second uplink BWP.

[0023] In certain embodiments, one or more uplink carriers may share the same uplink timing alignment and may be grouped into the same timing advance group (TAG). To prevent the UE from transmitting any uplink signals other than those associated with the random access procedure, a time alignment timer (TAT) may be considered expired. In some embodiments, a TAT may be associated with a TAG that includes the first BWP and the second BWP. In other words, to prevent the UE from transmitting any signals on the first BWP, a TAT associated with a TAG that includes the first BWP and / or the second BWP may be considered expired. Thus, the UE is not able to transmit any signals on the first BWP until it receives a new timing advance value from the network. The new timing advance value may be received through a random access procedure in which the time alignment timer is started again. The signal that the UE may attempt to transmit, for example, on the first BWP may be in response to a downlink assignment or an uplink grant received at the UE from a network entity that is unaware of the ongoing random access procedure.

[0024] In step 160, the UE may switch the active downlink BWP together with the switch from the first uplink bandwidth portion to the second uplink bandwidth portion shown in step 150. For example, when the triggered random access procedure is a contention-based random access procedure, the active downlink BWP is switched together with the switch from the first uplink BWP to the second uplink BWP. For example, the contention-based random access procedure may be triggered when a maximum number of media access control (MAC) layer scheduling requests is reached. The switch of the active downlink BWP together with the second uplink BWP may be performed so that the downlink BWP corresponds to the BWP in which the UE expects to receive a random access response from the network entity. Since it may not be possible for the network to identify the UE from the received preamble, the random access response may need to be transmitted in a known downlink BWP. Such a downlink BWP may be at least one of the downlink BWPs with a CSS.

[0025] On the other hand, certain embodiments may utilize a contention-free random access procedure, which may be triggered, for example, after a beam failure is detected by the UE or after a beam recovery request is sent by the UE. In the contention-free random access procedure, similar to the contention-based random access procedure, the UE may switch the active downlink BWP together with the switching of the first uplink bandwidth portion to the second uplink bandwidth portion. However, in other embodiments, the UE may keep the current downlink BWP of the contention-free random access procedure regardless of the switching of the first uplink BWP.

[0026] In certain embodiments, whether the UE switches or keeps the downlink BWP in a contention-free random access procedure can be configured by the network or a network entity therein. The network in such embodiments may identify the UE from the received preamble and may be able to respond with the previous downlink BWP. Some embodiments in which the network decides to keep or switch the downlink BWP may be used in paired spectrum where the downlink and uplink BWPs are configured or switched separately. In some embodiments, the previous downlink BWP can have a CSS, while in some other embodiments of the previous downlink BWP, the BWP can only have a UE-specific search space (USS).

[0027] In step 170, the UE may receive a contention resolution message from the network entity as part of the random access procedure. The contention resolution message is the fourth message of the contention-based random access procedure. A switch of at least one of the uplink BWP and / or the downlink BWP may occur upon receipt of the contention resolution message at the UE. In some embodiments, the contention resolution message is sent directly towards the C-RNTI of the UE, in which case a switch of at least one of the uplink BWP and / or the downlink BWP may be performed. In step 180, the UE may perform the random access procedure using a random access channel configured with the second uplink bandwidth portion. The described embodiments help to prevent erroneous network scheduling when the UE has already triggered the random access procedure. This reduces the amount of resources used by the network, thereby enhancing the capabilities of the network as a whole and of the network entities included therein.

[0028] FIG. 2 illustrates a system according to a particular embodiment. It should be understood that each block of FIG. 1 can be implemented by various means, such as hardware, software, firmware, one or more processors and / or circuits, or a combination thereof. In one embodiment, the system can include several devices, such as a network entity 220 or a UE 210. Although the system can include more than one UE 210 and more than one network entity 220, only one network entity is shown for illustrative purposes. The network entity may be a network node, an access node, a base station, an evolved NodeB (eNB), a gNB, a server, a host, or any of the other access or network nodes described herein.

[0029] Each of these devices may include at least one processor, controller, or module, shown as 211 and 221, respectively. At least one memory may be provided in each device, shown as 212 and 222, respectively. The memory may include computer program instructions or computer code contained therein. One or more transceivers 213 and 223 may be provided, and each device may also include an antenna, shown as 214 and 224, respectively. Although only one antenna is shown, many antennas and multiple antenna elements may be provided in each device. Higher category UEs generally include multiple antenna panels. Other configurations of these devices may also be provided, for example. For example, the network entity 220 and the UE 210 may be additionally configured for wired communication in addition to wireless communication, in which case the antennas 214 and 224 may exemplify any form of communication hardware, not just antennas.

[0030] Each of the transceivers 213 and 223 may independently be a unit or device that can be configured as a transmitter, a receiver or both a transmitter and a receiver, or both for transmission and reception. In other embodiments, the UAV or the network entity may have at least one separate receiver or transmitter. The transmitter and / or the receiver (as far as the radio part is concerned) may also be implemented as a remote radio head, not in the device itself, but for example located on a mast. The operations and functionality may be performed in a flexible manner in different entities such as nodes, hosts or servers. In other words, the division of labor may vary from case to case. One possible use is to have the network nodes distribute local content. One or more functionalities may also be implemented as software virtual application(s) that may run on the server.

[0031] The user device or user equipment may be a mobile station (MS) such as a mobile phone, a smartphone or a multimedia device, a computer such as a tablet with wireless communication capabilities, a personal data or personal digital assistant (PDA) with wireless communication capabilities, a portable media player with wireless communication capabilities, a digital camera, a pocket video camera, a navigation unit, or any combination thereof. In other embodiments, the UE may be a machine type communication (MTC) device or an Internet of Things device, which may not require human interaction such as a sensor, meter or actuator. The methods and / or processes illustrated in FIG. 1 may be performed by user equipment 210.

[0032] In some embodiments, an apparatus, e.g., user equipment 210 or network entity 220, may include means for performing the embodiments described above with respect to Fig. 1. In certain embodiments, at least one memory containing computer program code may be configured by at least one processor to cause the apparatus to perform at least any of the processes described herein. The apparatus may be, for example, user equipment 210 or network entity 220.

[0033] Processors 211 and 221 may be implemented by any computational or data processing device, such as a central processing unit (CPU), digital signal processor (DSP), application specific integrated circuit (ASIC), programmable logic device (PLD), field programmable gate array (FPGA), digitally enhanced circuit or equivalent device, or a combination thereof. The processors may be implemented as a single controller or multiple controllers or processors.

[0034] For firmware or software, an implementation may include at least one chipset module or unit (e.g., procedure, function, etc.). The memories 212 and 222 may each be any suitable storage device, such as a non-transitory computer-readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memory may be combined with a single integrated circuit as the processor or may be separate therefrom. Furthermore, the computer program instructions may be stored in the memory that can be processed by the processor and may be any suitable form of computer program code, such as a compiled or interpreted computer program written in any suitable programming language. The memory or data storage entity is usually internal, but may be external or a combination thereof, for example, when additional storage capacity is obtained from a service provider. The memory may be fixed or removable.

[0035] The memory and computer program instructions may be configured to cause a hardware apparatus, such as the network entity 220 or the UE 210, to execute any of the above processes (see, e.g., FIG. 1) by a processor for a particular device. Thus, in certain embodiments, the non-transitory computer-readable medium may be coded with computer instructions or one or more computer programs (e.g., added or updated software routines, applets, or macros) that, when executed in the hardware, can execute a process, e.g., one of the processes described herein. The computer program may be coded in a programming language, which may be a high-level programming language, e.g., object-C, C++, C#, Java, etc., or a low-level programming language, e.g., machine language or assembler. Alternatively, certain embodiments may be executed entirely in the hardware.

[0036] 2 illustrates a system including network entity 220 and UE 210, certain embodiments may be applicable to other configurations and configurations including additional elements, as illustrated and described herein. For example, there may be multiple user equipment devices and multiple network entities, or there may be other nodes providing similar functionality, such as nodes that combine the functionality of the user equipment and network entities, such as relay nodes. UE 210 may also have various configurations for communications other than with communication network entity 220. For example, UE 210 may be configured for device-to-device, machine-to-machine, and / or vehicle-to-vehicle transmissions.

[0037] The above-mentioned embodiments may provide significant improvements to the functionality of the network and / or to the functionality of the user equipment and the network entities included in the network. In particular, certain embodiments may enable the user equipment to perform a random access procedure even when the active or first uplink BWP does not support a random access channel. The UE may switch the first uplink BWP to a second BWP in which a random access channel is configured. Doing so helps to prevent errors in which the network may schedule a UE that has already failed a scheduling request and / or has already triggered a random access procedure.

[0038] Preventing such erroneous scheduling helps to reduce resources utilized by the network, thereby significantly improving the efficiency and throughput of the network as a whole. This increased efficiency not only improves the capabilities of the network entities included in the network, but also significantly improves the capabilities of user equipment by preventing unnecessary transmissions. For example, reducing unnecessary transmissions by the network can help reduce the amount of battery drained by user equipment.

[0039] The features, structures, or characteristics of a particular embodiment described throughout this specification may be incorporated in any suitable manner into one or more embodiments. For example, the use of the phrases "certain embodiments," "some embodiments," "other embodiments," or other similar language throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the present invention. Thus, the appearance of the phrases "certain embodiments," "some embodiments," "other embodiments," or other similar language throughout this specification does not necessarily refer to the same group of embodiments, but rather the described feature, structure, or characteristic may be incorporated in any suitable manner into one or more embodiments.

[0040] Those skilled in the art will readily appreciate that the invention described above can be implemented with steps in a different order and / or with hardware elements in a different configuration than that disclosed. Thus, while the invention has been described based on these preferred embodiments, it will be apparent to those skilled in the art that certain modifications, variations and alternative constructions will be apparent and will remain within the scope of the invention. Although many of the above-described embodiments relate to 3GPP® 5G or NR technology, the embodiments may also be applied to any other 3GPP® technology, such as Fourth Generation (4G), Third Generation (3G), LTE, LTE-A and / or Internet of Things.

[0041] Partial glossary 3GPP(registered trademark) Third Generation Partnership Project 5G fifth generation NR New Radio Technology gNB NR Node B UE User Equipment LTE Long Term Evolution LTE-A Advanced LTE PRACH Physical Random Access Channel RA-RNTI Random Access Radio Network Temporary Identifier C-RNTI Cell Radio Network Temporary Identifier RRC Radio Resource Control TMSI Temporary Mobile Subscriber Identifier FDD Frequency Division Duplex BWP Bandwidth section TDD Time Division Duplex CSS Common Search Space USS UE specific search space BLER Block Error Rate SSB sync signal block CSI-RS Channel State Information Reference Signal PCell Primary Cell PSCell Primary Secondary Cell TAG Timing Advance Group

Claims

1. triggering a random access procedure in a user equipment configured with a first uplink bandwidth portion not supporting a random access channel for the random access procedure and a second uplink bandwidth portion supporting the random access channel for the random access procedure; switching, at the user equipment, from the first uplink bandwidth portion to the second uplink bandwidth portion after the triggering of the random access procedure, wherein the switching is performed autonomously by the user equipment; performing, at the user equipment, the random access procedure using the random access channel configured with the second uplink bandwidth portion; Equipped with 4. The method of claim 3, wherein the switching comprises the user equipment autonomously deactivating the first uplink bandwidth portion and enabling the second uplink bandwidth portion.

2. The method of claim 1 , wherein a time alignment timer is considered to have expired.

3. 3. The method of claim 2, wherein the time alignment timer is associated with a timing advance group comprising at least one of the first uplink bandwidth portion and the second uplink bandwidth portion.

4. 4. The method of claim 1, further comprising: at the user equipment, switching an active downlink bandwidth portion together with the switching from the first uplink bandwidth portion to the second uplink bandwidth portion.

5. 5. The method of claim 4, wherein the switching of the active downlink bandwidth portion occurs when the triggered random access procedure is at least one of a contention-based random access procedure or a contention-free random access procedure.

6. receiving, at the user equipment, a configuration indication from a network entity; selecting the second uplink bandwidth portion from a plurality of bandwidth portions based on the configuration indication; The method of claim 1 , further comprising:

7. The method of claim 6 , wherein the network entity is included in a primary cell or a secondary cell.

8. The method according to claim 1 , wherein the first uplink bandwidth portion and the second uplink bandwidth portion are configured in the user equipment within a single cell.

9. 9. The method of claim 1, further comprising: selecting, at the user equipment, the second uplink bandwidth portion based on at least one of an implementation of the user equipment, a default bandwidth portion, a logical channel that triggers the random access procedure, or a priority of the logical channel.

10. 10. The method of claim 1, further comprising selecting, by the user equipment, the second uplink bandwidth portion based on at least one of a frequency of the random access channel or a frequency of the random access channel.

11. The method according to claim 1 , wherein the user equipment is in a radio resource control connected state during the triggering of the random access procedure.

12. 12. The method according to claim 1, wherein the triggering of the random access procedure occurs after a beam obstruction is detected by the user equipment.

13. A method according to any one of claims 1 to 6, wherein within a cell, the user equipment is configured with a plurality of uplink bandwidth portions supporting the random access channel.

14. The method according to claim 1 , wherein the second uplink bandwidth portion is an initial bandwidth portion.

15. At least one processor; and at least one memory containing computer program code, the at least one memory and the computer program code are configured to cause the at least one processor to execute at least a process on the user equipment; The process comprises: triggering a random access procedure in the user equipment configured with a first uplink bandwidth portion that does not support a random access channel for the random access procedure and a second uplink bandwidth portion that supports the random access channel for the random access procedure; switching, at the user equipment, from the first uplink bandwidth portion to the second uplink bandwidth portion after the triggering of the random access procedure, wherein the switching is performed autonomously by the user equipment; performing, at the user equipment, the random access procedure using the random access channel configured with the second uplink bandwidth portion; Equipped with The switching comprises the user equipment autonomously deactivating the first uplink bandwidth portion and enabling the second uplink bandwidth portion.

16. The user equipment of claim 15, wherein a time alignment timer is considered to have expired.

17. 17. The user equipment of claim 16, wherein the time alignment timer is associated with a timing advance group comprising at least one of the first uplink bandwidth portion and the second uplink bandwidth portion.

18. The at least one memory and the computer program code are transmitted by the at least one processor to the user equipment, at least 18. A user equipment according to any of claims 15 to 17, configured to cause a switch in active downlink bandwidth portion with said switch from said first uplink bandwidth portion to said second uplink bandwidth portion.

19. 20. The user equipment of claim 18, wherein the switching of the active downlink bandwidth portion occurs when the triggered random access procedure is at least one of a contention based random access procedure or a contention free random access procedure.

20. The at least one memory and the computer program code are transmitted by the at least one processor to the user equipment, at least receiving configuration instructions from a network entity; 20. A user equipment according to any of claims 15 to 19, configured to cause the second uplink bandwidth portion to be selected from a plurality of bandwidth portions based on the configuration indication.

21. The user equipment of claim 20 , wherein the network entity is included in a primary cell or a secondary cell.

22. 22. A user equipment according to any of claims 15 to 21, wherein the first uplink bandwidth portion and the second uplink bandwidth portion are configured in the user equipment within a single cell.

23. The at least one memory and the computer program code are transmitted by the at least one processor to the user equipment, at least 23. A user equipment according to claim 15, configured to cause the second uplink bandwidth portion to be selected based on at least one of an implementation of the user equipment, a default bandwidth portion, a logical channel that triggers the random access procedure, or a priority of the logical channel.

24. The at least one memory and the computer program code are transmitted by the at least one processor to the user equipment, at least 24. A user equipment according to any of claims 15 to 23, configured to cause the second uplink bandwidth portion to be selected based on at least one of a numerology or a frequency of the random access channel.

25. 25. A user equipment according to any of claims 15 to 24, wherein the user equipment is in a RADIO RESOURCE CONTROL CONNECTED state during the initiation of the random access procedure.

26. A user equipment as described in any of claims 15 to 20, wherein within a cell, the user equipment is configured with a plurality of uplink bandwidth portions supporting the random access channel.

27. 27. The user equipment of claim 15, wherein the second uplink bandwidth portion is an initial bandwidth portion.

28. code for triggering a random access procedure in a user equipment configured with a first uplink bandwidth portion that does not support a random access channel for a random access procedure and a second uplink bandwidth portion that supports the random access channel for the random access procedure; code for switching, at the user equipment, from the first uplink bandwidth portion to the second uplink bandwidth portion after the triggering of the random access procedure, the switching being performed autonomously by the user equipment; code for performing, at the user equipment, the random access procedure using the random access channel configured with the second uplink bandwidth portion; a computer program code including:

23. The method of claim 22, wherein the switching comprises the user equipment autonomously deactivating the first uplink bandwidth portion and enabling the second uplink bandwidth portion.

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