Coverage enhancement method

Abstract

Methods, devices, and non-transitory computer readable media are provided for determining a pre-compensated timing advance (TA) value for a PRACH between a user equipment (UE) and a base station. A distance between the UE and the base station is determined. Wireless channel model information is received from a base station. And receiving the transmitting power of the base station. Reference signal received power (RSRP) measurements are obtained, and path loss information is calculated based on the transmit power and the RSRP measurements. The pre-compensated TA value is determined based on the determined distance to the base station. And transmitting the PRACH to the base station by using the pre-compensated TA value.

Description

TECHNICAL FIELD

[0001] The present subject matter relates generally to wireless communications. In particular, the present subject matter relates to methods, devices and systems for enhancing cell coverage in initial access procedure of a wireless communication network. BACKGROUND

[0002] In conventional terrestrial cellular communication systems, an important function of the random access procedure (RACH) is to estimate the two-way propagation delay (round-trip delay) between the user equipment (UE) and the base station (e.g., gNB). The UE can transmit data to the base station by compensating for the propagation delay so that the data arrives at the base station at a time that is in a synchronized state. By compensating for the propagation delay, the UE can perform the transmission so that the arrival time with respect to a reference time for all users is within the protection range of the cyclic prefix (CP) and thus the orthogonal frequency division multiple access (OFDMA) can be maintained for all users. Therefore, by compensating for at least the propagation delay, the uplink reception of multiple users of the communication system of the orthogonal frequency division multiple access (OFDM) technology can be orthogonal and can not interfere with each other.

[0003] Conventional terrestrial cellular mobile communication systems, such as Long-Term Evolution (LTE) or New Radio (NR), can support up to 100km or 300km cell coverage distance for Physical Random Access Channel (PRACH) by extending the length of the random access preamble and the length of the random access signal guard time (e.g., by choosing an appropriate CP length) in combination with special base station reception techniques. However, for typical Fixed Wireless Access (FWA) scenarios or other possible scenarios, the wireless propagation environment is almost Line of Sight (LOS), the preamble length is no longer the bottleneck for coverage, and instead the CP length becomes the limiting factor. Due to the adoption of the short PRACH format shown in Table 1, the coverage of PRACH is limited by the CP length. The longest CP length provided by the short PRACH format (e.g., short PRACH format C2) in the table is the length of one PRACH OFDM symbol or the length of one preamble, i.e., 2048K·2^(-μ), the maximum coverage is about 9200m at subcarrier spacing SCS = 15KHz. If 120KHz SCS is used in FR2 frequency band, the coverage distance will be scaled down to 1160m.

[0004] Table 1: Short PRACH formats for SCS = 15KHz

[0005]

[0006] SUMMARY

[0007] The present subject matter relates to a method, device and system for improving measurement techniques in wireless communications. The present subject matter relates to determining a pre-compensated Timing Advance (TA) estimate for PRACH transmission when the TA or round trip latency introduced by the distance between a base station and a terminal exceeds the CP length of PRACH.

[0008] In some embodiments, a method for determining a pre-compensated Timing Advance (TA) value for PRACH between a user equipment (UE) and a base station includes determining a distance between the UE and the base station, determining the pre-compensated TA value based on the determined distance to the base station, and transmitting a PRACH to the base station using the pre-compensated TA value.

[0009] In some embodiments, a method of determining, by a base station, whether a user equipment (UE) is using pre-compensated timing advance (TA) includes defining a plurality of PRACH resource partitions, the PRACH resource partitions including pre-compensated TA partitions and non-pre-compensated TA partitions; detecting a PRACH received from the UE based on a selected PRACH resource partition; and determining whether the UE is using pre-compensated TA based on the selected PRACH resource partition.

[0010] In other embodiments, a wireless communication device can include a memory that stores instructions and a processing circuit in communication with the memory. When the processing circuit executes the instructions, the processing circuit is configured to perform the above-described method.

[0011] In other embodiments, a wireless communication device can include a memory that stores instructions and a processing circuit in communication with the memory. When the processing circuit executes the instructions, the processing circuit is configured to perform the above-described method.

[0012] In other embodiments, a computer-readable medium includes instructions that, when executed by a computer, cause the computer to perform the above-described method.

[0013] The above and other aspects and implementations thereof are more fully described in the following detailed description along with the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 Embodiments of a wireless communication system including one wireless base station and one or more user equipments are shown.

[0015] Figure 2 Embodiments of a base station are shown.

[0016] Figure 3 Embodiments of a user equipment (UE) are shown.

[0017] Figure 4 Embodiments of how a base station detects a PRACH are shown.

[0018] Figure 5 Embodiments of a timing diagram of how a UE determines a pre-compensated TA value are shown.

[0019] Figure 6 Embodiments of a timing diagram of how a UE can determine a pre-compensated TA value are shown.

[0020] Figure 7 Embodiments of determining an RSRP threshold in a base station and determining a timing advance (TA) in a user equipment are shown.

[0021] Figure 8A A flowchart of how a UE indicates pre-compensated TA to a base station is shown.

[0022] Figure 8B A flow diagram showing indicating a pre-compensated TA value from a UE to a base station is shown. DETAILED DESCRIPTION

[0023] The subject matter will be described in detail, with reference to the attached figures, which are incorporated in and constitute a part of this specification, and wherein like reference numerals indicate corresponding elements throughout the several views. It should be noted that the subject matter can be implemented in a variety of different forms and that the disclosed implementation in no way limits its scope. The subject matter is intended to cover all adaptations or variations of implementations described herein.

[0024] Throughout the specification and claims, the term "comprising" or variations such as "comprise" or "comprises" will be understood to imply a non-exclusive inclusion. Like terms have like definitions so that for example, "a", "an", or "the" are often used interchangeably with "one or more" or "one or more of each of. As used herein, the articles "a", "an", and "the" are used herein to refer to one or to more than one (i.e., to "one or more") of the associated noun terms. In this manner, the singular also includes the plural unless expressly stated otherwise. Unless otherwise noted, terms like "if" can be construed to mean "when" or "upon" or "in response to determining" or some similar timing. Similarly, the term "based on" can be construed to mean "based at least on" or "based at least in part on."

[0025] In general, the terms used will be construed to have a meaning consistent with their intended context. For example, terms such as "and", "or", or "and / or" as used herein may include a wide variety of meanings that can depend upon the context in which such terms are used. Typically, "or" if used to associate a list, such as A, B, or C, is intended to mean A, B, and C, here used in the inclusive sense, as well as A, B or C, here used in the exclusive sense. In addition, the term "one or more" or "at least one" as used herein, depending on the context, can be used to describe any feature, structure, or characteristic in the singular or can be used to describe combinations of features, structures or characteristics. Similarly, terms such as "a", "an", or "the" again, depending on the context, can be understood to convey a singular usage or to convey a plural usage. Further, the term "based on" or "determined based on" can be understood as not necessarily requiring exclusive consideration to convey a set of factors, but can allow for additional factors not explicitly described, again depending on the context.

[0026] Figure 1 A schematic diagram showing an exemplary wireless communication system 100 including a plurality of communication nodes (or simply nodes) configured to communicate wirelessly with each other is shown. Typically, the communication nodes include at least one user equipment 102 and at least one radio access node 104. Figure 1The example wireless communication system 100 in FIG. 1 is shown comprising two user devices 102 (including a first user device 102(1) and a second user device 102(2)) and one wireless access node 104. However, the wireless communication system 100 can also comprise other various examples, including any combination of one or more user devices 102 and / or one or more wireless access nodes 104.

[0027] Generally, a user device as described herein (e.g., the user devices 102) can include a single electronic device or apparatus capable of wireless communication over a network, or multiple (e.g., of a network) electronic devices or apparatuses. A user device can include or otherwise be referred to as a user terminal, user terminal device, or user equipment (UE). Additionally, a user device can be or include, but is not limited to, a mobile device such as a mobile phone, a smart phone, a smart watch, a tablet, a laptop, a vehicle or other vehicle (human-powered, motorized or engine-powered, such as a car, an airplane, a train, a ship, or a bicycle, as non-limiting examples), or a stationary device such as a desktop computer or other computing device that is not typically moved for long periods of time, such as an appliance, other relatively heavy device (including an Internet of Things (IoT) device, or a computing device used in a business or industrial setting, among other non-limiting examples). In different embodiments, the user devices 102 can include a transceiver circuit 106 coupled to an antenna 108 to enable wireless communication with the wireless access node 104. The transceiver circuit 106 can also be coupled to a processor 110, which can also be coupled to a memory 112 or other storage device. The memory 112 can store therein instructions or code that, when read and executed by the processor 110, cause the processor 110 to implement various methods described herein.

[0028] Furthermore, generally, a wireless access node as described herein, such as the wireless access node 104, can comprise a single electronic device or apparatus or multiple (e.g., of a network) electronic devices or apparatuses, and can comprise one or more base stations or other wireless network access points capable of wireless communication with one or more user devices and / or with one or more other wireless access nodes 104 over a network. For example, in various embodiments, the wireless access node 104 can comprise a 4G LTE base station, a 5G NR base station, a 5G central unit base station, a 5G distributed unit base station, a next generation Node B (gNB), an enhanced Node B (eNB), or other similar or next generation (e.g., 6G) base station. The wireless access node 104 can comprise a transceiver circuit 114 coupled to an antenna 116, which can comprise an antenna tower 118 in different approaches, to enable wireless communication with the user device 102 or another wireless access node 104. The transceiver circuit 114 can also be coupled to one or more processors 120, which can also be coupled to a memory 122 or other storage device. The memory 122 can store instructions or code that, when read and executed by the processor 120, cause the processor 120 to implement one or more methods described herein.

[0029] In various embodiments, two communication nodes in the wireless communication system 100, such as the user device 102 and the wireless access node 104, two user devices 102 without the wireless access node 104, or two wireless access nodes 104 without the user device 102, can be configured to wirelessly communicate with each other in or through a mobile network and / or wireless access network according to one or more standards and / or specifications. Generally, the standards and / or specifications can define rules or procedures in which the communication nodes can wirelessly communicate, which can include those for millimeter (mm) wave band communication and / or using multiple antenna schemes and beamforming functionality in different embodiments. Additionally or alternatively, the standards and / or specifications can define radio access technologies and / or cellular technologies, such as Fourth Generation (4G) Long Term Evolution (LTE), Fifth Generation (5G) New Radio (NR), or New Radio Unlicensed (NR-U), among other non-limiting examples.

[0030] Furthermore, in the wireless communication system 100, the communication nodes are configured to communicate wireless signals between each other. Generally, a communication between two communication nodes in the wireless communication system 100 can be or include a transmission or a reception, and typically both, simultaneously, depending on the perspective of the particular node in the communication. For example, for a particular communication between a first node and a second node, where the first node transmits a signal to the second node and the second node receives a signal from the first node, the first node can be referred to as a source or transmitting node / device, the second node can be referred to as a destination or receiving node / device, and the communication can be considered a transmission by the first node and a reception by the second node. Of course, since the communication nodes in the wireless communication system 100 can transmit and receive signals, a single communication node can be both a transmitting / source node and a receiving / destination node, or switch between being a source / transmitting node and a destination / receiving node, simultaneously.

[0031] Furthermore, a particular signal can be characterized or defined as an uplink (UL) signal, a downlink (DL) signal, or a sidelink (SL) signal. An uplink signal is a signal transmitted from a user equipment 102 to a radio access node 104. A downlink signal is a signal transmitted from a radio access node 104 to a user equipment 102. A sidelink signal is a signal transmitted from one user equipment 102 to another user equipment 102, or from one radio access node 104 to another radio access node 104. Furthermore, for a sidelink transmission, a first / source user equipment 102 transmits a sidelink signal directly to a second / destination user equipment 102 without the need to forward the sidelink signal to a radio access node 104.

[0032] Furthermore, a signal transmitted between communication nodes in the system 100 can be characterized or defined as a data signal or a control signal. Generally, a data signal is a signal that includes or carries data, such as multimedia data (e.g., voice and / or image data), and a control signal is a signal that carries control information that configures the communication nodes to communicate with each other in a particular manner, or otherwise controls how the communication nodes communicate with each other, data signals. Furthermore, certain signals can be defined or characterized by a combination of data / control and uplink / downlink / sidelink, including uplink control signals, uplink data signals, downlink control signals, downlink data signals, sidelink control signals, and sidelink data signals.

[0033] For at least some specifications such as 5G NR, data and control signals are transmitted and / or carried on physical channels. Generally, a physical channel corresponds to a set of time-frequency resources used for transmitting signals. Different types of physical channels can be used to transmit different types of signals. For example, a physical data channel (or data only channel) is used to transmit data signals, and a physical control channel (or control only channel) is used to transmit control signals. Exemplary types of physical data channels include, but are not limited to, a physical downlink shared channel (PDSCH) used to communicate downlink data signals, a physical uplink shared channel (PUSCH) used to communicate uplink data signals, and a physical sidelink shared channel (PSSCH) used to communicate sidelink data signals. Further, exemplary types of physical control channels include, but are not limited to, a physical downlink control channel (PDCCH) used to communicate downlink control signals, a physical uplink control channel (PUCCH) used to communicate uplink control signals, and a physical sidelink control channel (PSCCH) used to communicate sidelink control signals. For simplicity, unless otherwise specified, a particular type of physical channel is also used herein to refer to signals transmitted on that particular type of physical channel and / or transmissions on that particular type of transmission. For example, PDSCH refers to the physical downlink shared channel itself, downlink data signals transmitted on the PDSCH, or downlink data transmissions. Thus, a communication node transmitting or receiving PDSCH means that the communication node is transmitting or receiving signals on the PDSCH.

[0034] Further, for at least some specifications, such as 5G NR, and / or at least some types of control signals, the control signals transmitted by the communication nodes can include control information including information necessary for transmission of one or more data signals and / or scheduling of one or more data channels (or one or more transmissions on a data channel) between the communication nodes. For example, such control information can include information necessary for correct reception, decoding, and demodulation of data signals received on a physical data channel during a data transmission and / or an uplink scheduling grant informing a user equipment about resources and transmission format for an uplink data transmission. In some embodiments, the control information includes Downlink Control Information (DCI) transmitted in the downlink direction from the radio access node 104 to the user equipment 102. In other embodiments, the control information includes Uplink Control Information (UCI) transmitted in the uplink direction from the user equipment 102 to the radio access node 104 or Sidelink Control Information (SCI) transmitted in the sidelink direction from one user equipment 102(1) to another user equipment 102(2).

[0035] Additionally, in the wireless communication system 100, the time slot format for a plurality of time slots (occasions) or frames can be configured by the radio access node 104 or specified by a protocol. In some embodiments, a time slot can be indicated or designated as a downlink time slot, a flexible time slot, or an uplink time slot. Further, in different embodiments, an Orthogonal Frequency Divisional Multiplexing (OFDM) symbol can be indicated or designated as a downlink symbol, a flexible symbol, or an uplink symbol.

[0036] Figure 2 An embodiment of a base station 200 is shown. The example base station 200 can include radio transmit / receive (Tx / Rx) circuitry 208 to transmit / receive communications with UEs and / or other base stations. The base station 200 can also include network interface circuitry 209 to communicate the base station 200 with other base stations and / or a core network, e.g., optical or wired interconnections, Ethernet, and / or other data transmission media / protocols. The base station 200 can optionally include an input / output (I / O) interface 206 to communicate with an operator, etc.

[0037] The base station 200 can also include system circuitry 204. The system circuitry 204 can include a processor 221 and / or a memory 222. The memory 222 can include an operating system 224, instructions 226, and parameters 228. The instructions 226 can be configured for one or more processors 124 to perform the functions of the base station 200. The parameters 228 can contain parameters used to support execution of the instructions 226. For example, the parameters can include network protocol settings, bandwidth parameters, radio frequency mapping assignments, and / or other parameters.

[0038] Figure 3 An embodiment of a terminal device 300 (e.g., a user equipment, UE) is shown. The UE 300 can be a mobile device, such as a smartphone or a mobile communication module disposed in a vehicle. The UE 300 can include a communication interface 302, system circuitry 304, an input / output interface (I / O) 306, display circuitry 308, and a memory 309. The display circuitry can include a user interface 310. The system circuitry 304 can include any combination of hardware, software, firmware, or other logic / circuitry. For example, the system circuitry 304 can be implemented with one or more Systems on a Chip (SoCs), Application Specific Integrated Circuits (ASICs), discrete analog and digital circuitry, and other circuitry. The system circuitry 304 can be part of any desired functionality implementation in the UE 300. In this regard, the system circuitry 304 can include, as an embodiment, logic to facilitate decoding and playing music and videos, e.g., MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV decoding and playback; running applications; accepting user input; saving and retrieving application data; establishing, maintaining, and terminating cellular telephone calls or data connections, e.g., for Internet connectivity; establishing, maintaining, and terminating wireless network connections, Bluetooth connections, or other connections; and displaying relevant information on the user interface 310. The user interface 310 and the input / output (I / O) interface 306 can include a graphical user interface, a touch-sensitive display, tactile feedback or other haptic output, voice or facial recognition input, buttons, switches, a speaker, and other user interface elements. Other examples of the I / O interface 306 can include a microphone, a video and still image camera, a temperature sensor, a vibration sensor, a rotation and orientation sensor, earphone and microphone input / output jacks, a Universal Serial Bus (USB) connector, a memory card slot, a radiation sensor (e.g., an IR sensor), and other types of input.

[0039] Referring to Figure 3The communication interface 302 can include radio frequency (RF) transmit (Tx) and receive (Rx) circuitry 316 that handles transmission and reception of signals through one or more antennas 314. The communication interface 302 can include one or more transceivers. A transceiver can be a wireless transceiver that includes modulation / demodulation circuitry, digital to analog (DAC) converters, shaping tables, analog to digital (ADC) converters, filters, waveform shapers, preamplifiers, power amplifiers, and / or other logic used to transmit and receive through one or more antennas or, for some devices, through physical (e.g., wired) media. The signals transmitted and received can conform to any of a number of formats, protocols, modulation schemes (e.g., QPSK, 16-QAM, 64-QAM, or 256-QAM), frequency channels, bit rates, and coding. As a specific example, the communication interface 302 can include transceivers that support transmission and reception in accordance with 2G, 3G, BT, WiFi, Universal Mobile Telecommunications System (UMTS), High Speed Packet Access (HSPA)+, 4G / Long Term Evolution (LTE), and 5G standards. However, the technology described below can be applied to other wireless communication technologies, whether produced by the Third Generation Partnership Project (3GPP), GSM Association, 3GPP2, IEEE, or other partnership or standards body.

[0040] Referring to Figure 3 The system circuitry 304 can include one or more processors 321 and memory 322. The memory 322 stores, for example, an operating system 324, instructions 326, and parameters 328. The processor 321 is configured to execute the instructions 326 to perform the desired functions of the UE 300. The parameters 328 can provide and specify configuration and operational options for the instructions 326. The memory 322 can also store any BT, WiFi, 3G, 4G, 5G, or other data that the UE 300 will transmit through or has received via the communication interface 302. In different implementations, system power for the UE 300 can be supplied by a power storage device such as a battery or a transformer.

[0041] The subject matter describes several example implementations that can be partially or entirely implemented on the base station 200 and / or the UE 300 described with reference to Figures 1-5

[0042] ​The legacy NR system introduces basic schemes to support initial access in FR1 (<6GHz band) and FR2 (>6GHz band). The schemes include different Physical Random Access Channel (PRACH) format and PRACH resource configuration, and the definition of the relationship between Synchronization Signal Block (SSB) and PRACH, the mechanism of PRACH retransmission, the mechanism of PRACH power control, etc.

[0043] RACH Occasion (RO) is the time and frequency domain resource for PRACH transmission. There is a predefined association between SSB and RO, but the association in the basic PRACH procedure is not optimized for PRACH repeated transmission. As a result, the RO for PRACH repetition will be scattered to different association periods, resulting in an unacceptably long delay for the RACH procedure.

[0044] Figure 4 An exemplary behavior is shown to illustrate how the gNB 200 detects the PRACH. The gNB 200 can assume that the PRACH detection window covers all four preamble time zones where the PRACH should arrive. Figure 4 Four reception states are described. In the first reception state 401, the UE 300 can be very close to the gNB 200, where the Round Trip Delay (RTD) is equal to zero. In the second reception state 402, the UE 300 can be in the middle of the gNB coverage, with the RTD between 0 and one CP length (0 < RTD < 1CP). In the third reception state 403, the UE 300 can be far away from the gNB 200, at the cell edge, with the RTD equal to the CP length (RTD = 1CP). In the fourth reception state 404, the UE 300 can be outside the gNB coverage, with the additional delay possibly causing incomplete PRACH detection, and the gNB 200 can be at risk of failing to successfully detect the PRACH.

[0045] Currently, PRACH early transmission, i.e., open-loop pre-compensation of TA, can be used to solve the coverage bottleneck of PRACH due to the CP length limitation of random access. For example, based on the location information of the UE determined via a Global Navigation Satellite System (GNSS) and the base station location information broadcast by the base station 200, the UE 300 can determine the distance between the UE 300 and the base station 200, and can calculate a coarse TA value to initiate an uplink transmission. In this way, the random access signal can be sent in advance according to the pre-compensation TA value, so that the arrival of the PRACH falls within the detection window. This can eliminate the coverage bottleneck of PRACH and enhance the coverage of PRACH.

[0046] However, when the UE 300 does not have GNSS capability, a problem arises, which means that the UE 300 cannot know its own location and cannot calculate the relative distance between the base station 200 and the UE 300. In such a case, the pre-determined pre-compensation TA value for PRACH transmission cannot be determined. Therefore, according to the present subject matter, an alternative method of determining a coarse TA is described.

[0047] UE determines TA value through RSRP measurement value and channel model assumption

[0048] The Reference Signal Received Power (RSRP) measurement value is a mandatory function for the UE 300 in terms of expressing the signal level and quality.

[0049] The one-way propagation distance can be derived from a large-scale channel model and path loss. For example, a typical statistical large-scale channel model for a Rural Macrocell (RMa) Line of Sight (LOS) scenario can be illustrated by the following equation:

[0050]

[0051] PL1 = 20 log 10 (40πd 3D f c / 3) + min(0.03h 1.72 , 10) log 10 (d 3D ) - min(0.044h 1.72 , 14.77) + 0.002 log 10 (h)d 3D ;

[0052] PL2 = PL1(d BP ) + 40 log10 (d 3D / d BP ).

[0053] Figure 5 A timing diagram 600 is shown to illustrate how the UE 300 can determine a pre-compensated TA value from RSRP measurement values and wireless channel model information. In S501, the UE 300 can receive the base station transmit power 501 and the wireless channel model information 502 from the base station 200.

[0054] The UE 300 can obtain the wireless channel model information from the base station 200 using a variety of techniques. In one embodiment technique, the UE 300 can obtain from the base station 200 the name or index of a predefined channel model; such as UMa LOS of the 3GPP channel model series. In addition, the UE 300 can obtain from the broadcast of the base station 200 the height of the base station 200 and other parameters of the equation.

[0055] More channel models can be found in the 3GPP technical report TS 38.901, which discloses channel models including RMa LOS / NLOS, UMa LOS / NLS, UMi LOS / NLOS, Indoor LOS / NLOS, etc. Other channel models found in scientific journals and related literature can also be used.

[0056] In another embodiment technique, the UE 300 can obtain from the base station 200 the characteristic parameters of a wireless channel model. For example, if a generic large-scale channel model is predefined as The base station 200 can only need to indicate to the UE 300 the propagation coefficient n and / or PL(d0). PL(d0) can be understood as the path loss for a reference distance.

[0057] In another embodiment technique, the UE 300 can always assume that the large-scale channel model is the well-known free-space propagation model; therefore, no other indication can be needed from the base station 200.

[0058] Generally, the more information provided by the base station 200, the more accurate the distance estimation in S507 can be.

[0059] Optionally, the base station 200 can configure the penetration loss in S502. A UE 300 located inside a building, whose distance to the base station 200 is derived from the path loss and the radio channel model information, and without considering the additional penetration loss, can estimate its distance to the base station 200 to be further than the actual distance. The UE 300 in the extreme coverage scenario described previously (e.g., inside a building) can be a fixed location terminal such as a Fixed Wireless Access (FWA) terminal or a Customer Premise Equipment (CPE) terminal. The UE 300 can always assume the additional penetration loss in the radio channel model and use it for distance estimation. The additional penetration loss can be pre-configured by the operator at terminal deployment (i.e., provide the penetration loss information), or can be configured (S502) by the base station through Over-the-Air Technology (OTA) techniques.

[0060] The UE 300 can obtain the RSRP measurement in S503 and calculate the path loss in S504 according to the following equation:

[0061] Path loss = Transmit power - RSRP measurement.

[0062] For example, the RSRP measurement of the base station 200 (S503) and the transmit power 501 can be obtained via System Information (SI).

[0063] If the base station 200 does not configure the penetration loss in S502, the UE 300 can optionally obtain a pre-configured penetration loss in S505 based on the assumption made on the radio channel model information 502, as explained previously. It is noted that steps S502 and S505 can not exist at the same time, only one of the options is implemented.

[0064] The accuracy of the distance estimation based on the path loss (equivalent to the RSRP measurement) and the radio channel model information can be significantly negatively impacted by whether the terminal is inside a building or outside a building. Building walls, glass, and other building materials can absorb, reflect, or refract the wireless signal, thus degrading the received power of the signal for a UE 300 located inside a building. Statistically, the additional attenuation of the wireless signal due to building materials can be between 8 dB to 25 dB. This attenuation problem can be addressed by incorporating the penetration loss into the path loss estimation in a subsequent step S506, which can improve the accuracy of the distance estimation in S507 and the determined pre-compensation TA value in S508.

[0065] The penetration loss obtained by S502 and / or S505 can be added to the path loss calculated in S504 to improve the accuracy of the path loss estimation in S506.

[0066] After the path loss is calculated, in S507, the UE 300 can determine the distance between the UE 300 and the base station 200 according to the radio channel model information (502) and the path loss.

[0067] In summary, the pre-compensated TA value for PRACH transmission can be determined in advance. The UE 300 can determine the TA value for PRACH transmission based on its distance to the base station 200; for example, TA value = 2 x (distance to base station / speed of light). The distance between the base station 200 and the UE 300 can be derived from the path loss and the radio channel model. The path loss can be calculated based on the transmit power 501 and the RSRP measurement value (S503) from the UE 300.

[0068] UE determines coarse TA value through RSRP measurement value and RSRP threshold

[0069] In the prior art, the distance between the base station 200 and the UE 300 can be estimated at the UE side based on the RSRP measurement value and the radio channel model information. In Figure 6 In the second method 600 shown in the prior art, the base station side can determine a plurality of RSRP thresholds in S601 based on the typical distance between the base station 200 and the UE 300 and the radio channel model information.

[0070] Figure 7 The process 700 of determining the RSRP threshold (S601) in the base station 200 and the pre-compensated TA value in the UE 300 is shown in the prior art.

[0071] As Figure 7As shown, a typical distance 705 between the base station 200 and the UE 300 can be associated with the CP length and preamble length of a PRACH format. A first distance can be determined by 0.5 x CP length, i.e. the distance light travels in half the time of the CP length. A second distance can be determined by 0.5 x (CP length + one preamble length), i.e. the distance light travels in half the time of the CP length plus one preamble length. A third distance can be determined by 0.5 x (CP length + two preamble lengths), i.e. the distance light travels in half the time of the CP length plus two preamble lengths. More distances can be derived in a similar manner according to the above examples. The determined distances can closely correspond to the PRACH reception window start point, which can be at the start of the first preamble, the start of the second preamble, the start of the third preamble, etc. Because the typical distance between the base station 200 and the UE 300 can be considered as a one-way distance 705, while the PRACH latency is a two-way latency, the factor 0.5 is used.

[0072] The above first, second and third distances are related to the specific implementation of the base station 200. It should be appreciated that the typical distance between the base station 200 and the UE 300 can also be determined by other principles, depending on the implementation of the base station 200.

[0073] Continuing to refer to Figure 7 After determining the multiple distances, the corresponding path losses 710 can be determined based on the wireless channel model. Subsequently, the RSRP threshold 715 can be calculated in S601 Figure 6 based on RSRP threshold = transmit power - path loss.

[0074] Returning to Figure 6 The additional penetration loss due to the UE 300 being located inside a building can be accounted for and can be optionally merged with the RSRP threshold in S602. For example, if the penetration loss is 25 dB, and the original RSRP threshold based on distance is -90 dB, the merged RSRP threshold can be represented as -90 - 25 = -115 dB. This is in contrast to the above method of Figure 5 In the method of Figure 5 , the UE 300 can optionally determine the penetration loss in S505. However, in the absence of performing S602, the above method of Figure 5 can also be employed in which the UE 300 determines the penetration loss.

[0075] In S603, the base station 200 can configure multiple sets of RSRP thresholds for the UE 300, and send these RSRP thresholds to the UE. The UE 300 can select a set of RSRP thresholds according to the UE type, the UE common deployment location, etc.

[0076] The base station 200 can also configure RSRP threshold offsets for the "in-building" scenario based on a base set of RSRP thresholds for the "out-of-building" scenario by the UE 300, and optionally indicate the set of RSRP threshold offsets to the UE 300 in S604.

[0077] In S605, the UE 300 can obtain the RSRP measurement via SI.

[0078] Optionally, in S606, the UE 300 can select one of the multiple RSRP threshold offsets and combine it with the RSRP threshold received in S603. For example, if the penetration loss is 25 dB, the offset is also 25 dB; if the original RSRP threshold based on distance is -90 dB, the combined RSRP threshold can be expressed as -90-25 = -115 dB. It is noted that steps S602 and S606 can not exist at the same time, only one of them is implemented.

[0079] In S607, the RSRP measurement of S605 can be compared with each of the multiple RSRP thresholds. If the RSRP measurement of S605 is less than one threshold, the UE 300 can select the corresponding distance in S608. As in the above method 600, the pre-compensation TA value for PRACH can be determined in S609 based on the distance determined in S608. If the above example (first, second, third) distances are used, the pre-compensation TA value can correspond to one CP length, one CP length plus one preamble length, or one CP length plus two preamble lengths, corresponding to the first RSRP threshold, the second RSRP threshold, or the third RSRP threshold, respectively.

[0080] Alternatively, based on similar principles, path loss thresholds can be determined in the base station 200 instead of RSRP thresholds, and similarly provided to the UE 300 for comparison and TA determination.

[0081] In summary, the pre-compensation TA value for PRACH transmission can be determined in advance. The UE 300 can determine the PRACH TA value by comparing the RSRP measurement with the RSRP threshold (S607). The RSRP threshold can be determined in the base station 200 (S601) and received by the UE 300 from the base station 200 (S603). The RSRP threshold can be determined by the base station 200 based on the transmission power and multiple path losses (S601), and provided to the UE 300 (S603). The UE 300 can determine the RSRP measurement (S605) and compare it with the RSRP threshold (S607). The UE 300 can determine the TA value based on the comparison (S608) and use the TA value for PRACH transmission (S609). Figure 7). The multiple path losses 710 can be determined based on the multiple distances 705 and the wireless channel model information. In typical embodiments, the multiple distances 705 between the base station 200 and the UE 300 can be based on the CP length and the preamble length of the PRACH format. The distance can be the distance that light travels in the time of the CP length + N preamble length. The base station 200 can provide the RSRP threshold offset or multiple sets of RSRP threshold to the UE 300 (S604) to address the additional penetration loss due to the UE 300 being inside a building.

[0082] Pre-compensation TA value indication embodiments

[0083] Performing PRACH transmission based on pre-compensation TA value is the behavior of the UE 300, but the base station 200 can not know whether the UE 300 is using pre-compensation TA transmission or not, nor the TA value size of the PRACH transmission. The pre-compensation TA value can be valid in the UE 300 and can be applied to the subsequent PUSCH, such as msg3 PUSCH, scheduled PUSCH, etc. However, if the base station 200 does not know whether the UE 300 is using pre-compensation TA transmission or the corresponding pre-compensation TA value, the base station 200 can not be able to determine the UL transmission delay due to the long distance between the base station 200 and the UE 300. Therefore, these timing issues should be addressed in subsequent Figure 8A and 8B described in the third method.

[0084] The first timing issue is that the base station 200 does not know whether pre-compensation TA is being used or not, nor the corresponding pre-compensation TA value. This uncertainty can lead to scheduling an incorrect HARQ process for data transmission. The second timing issue is that the base station 200 can not know when to receive the PUSCH from the UE 300. The third timing issue is that the scheduling timing can be too strict or the UE 300 does not have enough time to prepare the PUSCH.

[0085] To address the above issues, the UE 300 can indicate to the base station 200 during the initial access procedure or in the early stage of RRC connection whether pre-compensation is being used, and if so, the pre-compensation TA value can also be indicated, which will be described below.

[0086] Referring to Figure 8AIn the first technique 800, PRACH resources can be partitioned to distinguish different types of RACH procedures or RACH features. For example, a first resource partition 801 for non-pre-compensated TA and a second resource partition 802 for pre-compensated TA can be defined. When the UE 300 decides the RACH type, the UE 300 can select the corresponding PRACH resource (i.e., 801 or 802) in S805. When the base station 200 detects the PRACH, the base station 200 can know (S810) whether the UE 300 is using pre-compensated TA based on the selected PRACH resource 801 / 802. As shown in Figure 8A Figure 8, the first resource partition 801 means no pre-compensated TA is used, while the second resource partition 802 means pre-compensated TA is used. Similar principles can be employed to implicitly indicate to the base station 200 that the UE 300 is transmitting PRACH using pre-compensated TA.

[0087] A new set of PRACH resources can be defined in the base station 200 for pre-compensated TA. If the UE 300 performs pre-compensated TA processing according to the previously disclosed techniques, the UE 300 can select a specific PRACH resource for PRACH transmission with pre-compensated TA. In this way, the base station 200 will know that the UE 300 is transmitting using pre-compensated TA.

[0088] Furthermore, the UE 300 can continue to indicate the fine (compared to the coarse value) pre-compensated TA value in the msg3 PUSCH. When the RACH procedure ends, the base station 200 can obtain all information about the pre-compensated TA. Alternatively, the pre-compensated TA value can be provided in a subsequent PUSCH (instead of the msg3 PUSCH in the early stage of RRC connection). If the UE 300 does not need pre-compensated TA processing, there is no need to provide the pre-compensated TA value in the subsequent PUSCH. Therefore, this method maintains backward compatibility with the legacy procedure.

[0089] Referring to Figure 8BUnlike the first technique 800 where only one set of PRACH resources is defined for the pre-compensation TA, in the second technique 850, the defined PRACH resources can be partitioned into multiple sets, each corresponding to a different TA value of the PRACH pre-compensation TA. For example, a first resource partition corresponding to a first pre-compensation TA value 851 and a second resource partition corresponding to a second pre-compensation TA value 852 can be defined. The UE 300 can determine the pre-compensation TA value by selecting a set of partitioned PRACH resources (S855), and the base station 200 can directly learn the (coarse) pre-compensation TA value from the PRACH transmission (S860). As with the first technique, a fine (as opposed to coarse) pre-compensation TA value can be provided in a subsequent PUSCH (e.g., msg3 PUSCH). The fine pre-compensation TA value can have a higher granularity and / or accuracy than the coarse pre-compensation TA value.

[0090] In summary, the third method 800 / 850 implicitly indicates to the base station 200 whether a pre-compensation TA is being used after determining the pre-compensation TA value based on the first or second method (500 / 600) described above, and if so, can further indicate the pre-compensation TA value. The PRACH resource partitioning can be used to indicate whether a pre-compensation TA is being used, and if so, can further indicate a coarse pre-compensation TA value to the base station 200. A subsequent PUSCH (e.g., msg3 PUSCH or scheduled PUSCH) can further indicate a fine pre-compensation TA value.

[0091] The above description and drawings provide specific exemplary embodiments and implementations. However, the described subject matter can be embodied in various different forms and, therefore, the claimed subject matter is not limited to any exemplary embodiments set forth herein. Reasonable and intended variations are intended to be covered by the claimed subject matter. For example, the subject matter can be embodied as an article of manufacture, a method, a device, a component, a system, or a non-transitory computer-readable medium storing computer code. Accordingly, embodiments can be embodied in the form of hardware, software, firmware, a storage medium or any combination thereof. For example, the above-described method embodiments can be implemented by a component, device or system including a memory and a processor by executing computer code stored in the memory.

[0092] Throughout the specification and claims, the term "may" can convey the possible inclusion of one or more elements, and a possibility that one or more elements are not included. The term "including" as used herein, means "comprising" in the sense of open-endedness. Likewise, the phrase "in one embodiment / implementation" as used herein does not necessarily refer to the same embodiment and the phrase "in another embodiment / implementation" as used herein does not necessarily refer to a different embodiment. For example, a claimed subject matter can be implemented in a single embodiment / implementation, or can be implemented in multiple embodiments / implementation, or a combination thereof.

[0093] Generally, the terminology can be understood at least in part from usage of the singular throughout the present description. For example, terms, such as "and", "or", or "and / or", as used herein, can include a variety of meanings that can depend at least in part upon the context in which such terms are used. Typically, "or" if used to associate a list, such as A, B or C, is intended to mean A, B, and C, here used in the inclusive sense, as well as A, B or C, here used in the exclusive sense. In addition, the term "one or more" as used herein, at least in part, depending on the context, can be taken to describe any feature, structure or characteristic in the singular or can be taken to describe combinations of features, structures or characteristics in the plural. Similarly, the terms, such as "a", "an", or "the", again, can be understood to mean a singular usage or plural usage, at least in part, depending on the context in which such terms are used. Additionally, the term "based on" can be understood as not necessarily requiring explicit description of a set of factors based on which a decision is made, and can instead allow for a decision to be made based on additional factors that are not explicitly described.

[0094] Reference to features, advantages, or similar terms in the present document does not mean that all of the features and advantages that can be implemented in the solution should be or are included in any single implementation of the solution. Rather, the language is understood to mean that certain features, advantages or characteristics that are described in connection with one or more embodiments can be included in at least one embodiment of the solution. It will thus be understood that the discussion of features and advantages, and similar language, in relation to one or more embodiments can but need not refer to the same embodiment.

[0095] Furthermore, the described features, advantages, and characteristics of the solution can be combined in any suitable manner in one or more embodiments. One of ordinary skill in the related art will recognize that the solution can be practiced without one or more of the specific features or advantages of a particular embodiment. In other embodiments, additional features and advantages can be realized that are not described in connection with a certain embodiment but that are possible within the scope of the solution.

[0096] The subject matter of the present disclosure can also relate to or include the following aspects:

[0097] The first aspect includes a method for determining a pre-compensation timing advance (TA) value of a PRACH between a user equipment (UE) and a base station, comprising: determining a distance between the UE and the base station; determining the pre-compensation TA value based on the determined distance to the base station; transmitting the PRACH to the base station using the pre-compensation TA value.

[0098] The second aspect includes the method according to the first aspect, further comprising: receiving wireless channel model information; receiving a transmit power of the base station.

[0099] The third aspect includes the method of any of the preceding aspects, further comprising: obtaining a reference signal received power (RSRP) measurement; calculating path loss information based on the transmit power and the RSRP measurement.

[0100] The fourth aspect includes the method of any of the preceding aspects, wherein the radio channel model information comprises one or more of: a name or index of a predefined channel model; a height of the base station; a characteristic parameter of the radio channel model information; a propagation coefficient; or a path loss of a reference distance.

[0101] The fifth aspect includes the method of any of the preceding aspects, wherein the radio channel model information comprises a free space propagation model.

[0102] The sixth aspect includes the method of any of the preceding aspects, wherein the radio channel model information is received from the base station.

[0103] The seventh aspect includes the method of any of the preceding aspects, further comprising: obtaining penetration loss information.

[0104] The eighth aspect includes the method of any of the preceding aspects, wherein the penetration loss information is configured by the base station and received from the base station.

[0105] The ninth aspect includes the method of any of the preceding aspects, wherein the penetration loss information is determined by the UE based on the radio channel model information.

[0106] The tenth aspect includes the method of any of the preceding aspects, further comprising: obtaining a reference signal received power (RSRP) measurement; calculating path loss information based on the transmit power and the RSRP measurement; merging the penetration loss information with the path loss information.

[0107] The eleventh aspect includes the method of any of the preceding aspects, wherein the distance between the UE and the base station is determined based on the path loss information and the radio channel model information.

[0108] The twelfth aspect includes the method of any of the preceding aspects, further comprising: receiving a plurality of path loss thresholds or a plurality of RSRP thresholds from the base station; obtaining an RSRP measurement; comparing the RSRP measurement with the plurality of RSRP thresholds, wherein the distance between the UE and the base station is determined based on the comparison result.

[0109] The thirteenth aspect includes the method of any of the preceding aspects, further comprising: receiving a plurality of path loss thresholds from the base station; obtaining an RSRP measurement; determining a path loss based on the RSRP measurement and the transmit power; comparing the path loss with the plurality of path loss thresholds, wherein the distance between the UE and the base station is determined based on the comparison result.

[0110] The fourteenth aspect includes the method of any of the preceding aspects, wherein the RSRP threshold is based on a plurality of distances, the plurality of distances being based on a cyclic prefix (CP).

[0111] The fifteenth aspect includes the method of any of the preceding aspects, wherein the plurality of distances includes a first distance and a second distance, at least one of the first distance and the second distance being further based on a preamble length.

[0112] The sixteenth aspect includes the method of any of the preceding aspects, wherein the determined pre-compensation TA value corresponds to one of: one CP length; one CP length plus one preamble length of the PRACH; or one CP length plus two preamble lengths of the PRACH.

[0113] The seventeenth aspect includes the method of any of the preceding aspects, further comprising: receiving a set of RSRP threshold offsets due to penetration loss.

[0114] The eighteenth aspect includes the method of any of the preceding aspects, further comprising: selecting one of a plurality of RSRP threshold offsets; merging the plurality of threshold offsets with a plurality of path loss thresholds or a plurality of RSRP thresholds.

[0115] The nineteenth aspect includes a method for determining, by a base station, whether a pre-compensation timing advance (TA) is being used by a user equipment (UE), comprising: defining a plurality of PRACH resource partitions including pre-compensation timing advance (TA) partitions and non-pre-compensation TA partitions; detecting a PRACH received from the UE based on a selected PRACH resource partition; determining whether the UE is using a pre-compensation TA based on the selected PRACH resource partition.

[0116] The twentieth aspect includes the method of any of the preceding aspects, wherein the pre-compensation TA employs a coarse TA value; and the method further comprises: receiving a msg3 PUSCH or a scheduled PUSCH including a fine TA value, the fine TA value having a higher granularity than the coarse TA value.

[0117] The twenty-first aspect includes the method of any of the preceding aspects, wherein each of the plurality of PRACH resource partitions further includes a plurality of different pre-compensation TA values.

[0118] The twenty-second aspect includes the method of any of the preceding aspects, further comprising: determining, based on the selected PRACH resource partition, a pre-compensation TA value being used by the UE.

[0119] The twenty-third aspect includes the method of any of the preceding aspects, wherein the pre-compensation TA value is a coarse TA value; and the method further includes receiving a msg3 PUSCH or a scheduled PUSCH including a fine TA value, the fine TA value having a higher granularity than the coarse TA value.

[0120] The twenty-fourth aspect includes a non-transitory computer-readable medium comprising instructions to, when executed by one or more processors, cause performance of the method of any of the preceding aspects.

[0121] The twenty-fifth aspect includes an apparatus for wireless communication, comprising a processor; and a memory in communication with the processor, the memory storing a plurality of instructions executable by the processor to cause the apparatus to perform the method of aspects 1-23.

Claims

1. A method for determining a pre-compensation timing advance (TA) value of a physical random access channel (PRACH) between a user equipment (UE) and a base station, comprising: determining a distance between the UE and the base station; determining the pre-compensation TA value based on the determined distance to the base station; transmitting a PRACH to the base station using the pre-compensation TA value. 2.The method of claim 1, further comprising: receiving wireless channel model information; receiving a transmit power of the base station. 3.The method of claim 2, further comprising: obtaining a reference signal received power (RSRP) measurement; calculating path loss information based on the transmit power and the RSRP measurement.

4. The method of claim 2, wherein, the wireless channel model information comprises one or more of: a name or an index of a predefined channel model; a height of the base station; a characteristic parameter of the wireless channel model information; a propagation coefficient; or a path loss of a reference distance.

5. The method of claim 2, wherein, the wireless channel model information comprises a free space propagation model.

6. The method of claim 2, wherein, the wireless channel model information is received from the base station. 7.The method of claim 2, further comprising: obtaining penetration loss information.

8. The method of claim 7, wherein, the penetration loss information is configured by the base station and received from the base station.

9. The method of claim 7, wherein, the penetration loss information is determined by the UE based on the wireless channel model information. 10.The method of claim 7, further comprising: obtaining a reference signal received power (RSRP) measurement; calculating path loss information based on the transmit power and the RSRP measurement; combining the penetration loss information with the path loss information.

11. The method of claim 3, wherein, the distance between the UE and the base station is determined based on the path loss information and the wireless channel model information. 12.The method of claim 1, further comprising: receiving a plurality of path loss thresholds or a plurality of RSRP thresholds from the base station; obtaining an RSRP measurement; comparing the RSRP measurement with the plurality of RSRP thresholds, wherein the distance between the UE and the base station is determined based on a comparison result. 13.The method of claim 2, further comprising: receiving a plurality of path loss thresholds from the base station; obtaining an RSRP measurement; determining a path loss based on the RSRP measurement and the transmit power; comparing the path loss with the plurality of path loss thresholds, wherein the distance between the UE and the base station is determined based on a comparison result. 14.The method of claim 12, wherein: the plurality of RSRP thresholds are based on a plurality of distances, the plurality of distances are based on a cyclic prefix (CP). 15.The method of claim 14, wherein: the plurality of distances comprise a first distance and a second distance, at least one of the first distance and the second distance is further based on a preamble length.

16. The method of claim 14, wherein, the determined pre-compensation TA value is equivalent to one of: one CP length; one CP length plus one preamble length of a PRACH; or one CP length plus two preamble lengths of a PRACH. 17.The method of claim 12, further comprising: receiving a set of RSRP threshold offsets due to penetration loss.

18. The method of claim 17, further comprising: selecting one of a plurality of RSRP threshold offsets; combining the plurality of RSRP threshold offsets with the plurality of path loss thresholds or the plurality of RSRP thresholds.

19. A method for determining, by a base station, whether a user equipment (UE) is using pre-compensated timing advance (TA), comprising: defining a plurality of PRACH resource partitions, the PRACH resource partitions comprising pre-compensated TA partitions and non-pre-compensated TA partitions; detecting a PRACH received from the UE based on a selected PRACH resource partition; determining whether the UE is using pre-compensated TA based on the selected PRACH resource partition.

20. The method of claim 19, wherein, the pre-compensated TA employs a coarse TA value; and the method further comprising: receiving a msg3 PUSCH or a scheduled PUSCH comprising a fine TA value, the fine TA value having a higher granularity than the coarse TA value.

21. The method of claim 19, wherein, each of the plurality of PRACH resource partitions further comprises a plurality of different pre-compensated TA values.

22. The method of claim 21, further comprising: determining a pre-compensated TA value being used by the UE based on the selected PRACH resource partition.

23. The method of claim 22, wherein, the pre-compensated TA value is a coarse TA value; and the method further comprising: receiving a msg3 PUSCH or a scheduled PUSCH comprising a fine TA value, the fine TA value having a higher granularity than the coarse TA value.

24. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors, are adapted to carry out the method of claim 1 or 19.

25. An apparatus for wireless communication, comprising: a processor; a memory in communication with the processor, the memory storing a plurality of instructions executable by the processor to cause the apparatus to implement the method of claim 1 or 19.

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