WO2024221726A1

WO2024221726A1 - Physical random access channel system access

Info

Publication number: WO2024221726A1
Application number: PCT/CN2023/120886
Authority: WO
Inventors: Peng Hao
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2023-09-22
Filing date: 2023-09-22
Publication date: 2024-10-31
Anticipated expiration: 2026-03-22

Abstract

In wireless communication, there may be different protocols for setting up and synchronizing the communication between the basestation and the UE. Initial access may include a time period ahead of downlink (DL) timing. One example is a physical random access channel (PRACH) transmission. In other examples, PRACH transmission may also be used for a timing advance (TA) update. The system access timing may enable an efficient PRACH design and system access, which reduces PRACH overhead and efficiently supports larger cell coverage.

Description

PHYSICAL RANDOM ACCESS CHANNEL SYSTEM ACCESS

TECHNICAL FIELD

This document is directed generally to wireless communications. More specifically, wireless communication is improved by a configuration design and system access, such as through a physical random access channel (PRACH) configuration.

BACKGROUND

Wireless communication technologies are moving the world toward an increasingly connected and networked society. Wireless communications rely on efficient network resource management and allocation between user mobile stations and wireless access network nodes (including but not limited to wireless base stations) . A new generation network is expected to provide high speed, low latency and ultra-reliable communication capabilities and fulfil the requirements from different industries and users, including artificial intelligence (AI) requirements. As a result, user mobile stations or user equipment (UE) are becoming more complex and the amount of data communicated continually increases. Likewise, the quantity and variety of devices communicating over the network is also increasing. The initial access communications that are used for connecting UE with the network is also increasing in complexity. In order to improve communications and meet reliability requirements for the vertical industry as well as support the new generation network service, communication improvements should be made.

SUMMARY

This document relates to methods, systems, and devices for wireless communication, including initial access communication may be through different protocols for setting up and synchronizing the communication between the basestation and the UE. Initial access may include a time period ahead of downlink (DL) timing. One example is a physical random access channel (PRACH) transmission. In other examples, PRACH transmission may also be used for a timing advance (TA) update. The system access timing may enable an efficient PRACH design and system access, which reduces PRACH overhead and efficiently supports larger cell coverage.

In one embodiment, a method for wireless communication includes sending a signal with a protocol a time period ahead of a downlink (DL) timing; and applying a timing advance for uplink (UL) signals based on the time period.

In one embodiment, a method for wireless communication includes selecting, by a user equipment (UE) a time period from a set of time periods and sending signals based on the selected time period.

In one embodiment, a method for wireless communication includes estimating an area index for sending uplink (UL) signals; and sending signals based on the area index.

In one embodiment, a method for wireless communication includes indicating one or more Physical Random Access Channel (PRACH) protocol configurations; and indicating one or more sets of time periods or one or more cell division strategies, wherein each of the PRACH protocol configurations are associated with one set of time periods or associated with one cell division strategy.

In one embodiment, a wireless communications apparatus comprises a processor and a memory, and the processor is configured to read code from the memory and implement any of the embodiments discussed above.

In one embodiment, a computer program product comprises a computer-readable program medium code stored thereupon, the code, when executed by a processor, causes the processor to implement any of the embodiments discussed above.

In some embodiments, there is a wireless communications apparatus comprising a processor and a memory, wherein the processor is configured to read code from the memory and implement any methods recited in any of the embodiments. In some embodiments, a computer program product comprising a computer-readable program medium code stored thereupon, the code, when executed by a processor, causing the processor to implement any method recited in any of the embodiments. The above and other aspects and their implementations are described in greater detail in the drawings, the descriptions, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example basestation;

FIG. 2 shows an example random access (RA) messaging environment;

FIG. 3 shows one embodiment of initial access signaling;

FIG. 4 shows an embodiment of a random access channel (RACH) preamble format;

FIG. 5 shows an embodiment of a physical random access channel (PRACH) timing;

FIG. 6A shows an embodiment of positioning of user equipment (UE) relative to a basestation;

FIG. 6B shows another embodiment of positioning of user equipment (UE) relative to a basestation;

FIG. 7 shows an embodiment of a timing diagram for a physical random access channel (PRACH) ;

FIG. 8 shows another embodiment of a timing diagram for a physical random access channel (PRACH) ;

FIG. 9 shows an embodiment of frequency locations for a physical random access channel (PRACH) configuration; and

FIG. 10 shows another embodiment of a timing diagram for a physical random access channel (PRACH) .

DETAILED DESCRIPTION

The present disclosure will now be described in detail hereinafter with reference to the accompanied drawings, which form a part of the present disclosure, and which show, by way of illustration, specific examples of embodiments. Please note that the present disclosure may, however, be embodied in a variety of different forms and, therefore, the covered or claimed subject matter is intended to be construed as not being limited to any of the embodiments to be set forth below.

Throughout the specification and claims, terms may have nuanced meanings suggested or implied in context beyond an explicitly stated meaning. Likewise, the phrase “in one embodiment” or “in some embodiments” as used herein does not necessarily refer to the same embodiment and the phrase “in another embodiment” or “in other embodiments” as used herein does not necessarily refer to a different embodiment. The phrase “in one implementation” or “in some implementations” as used herein does not necessarily refer to the same implementation and the phrase “in another implementation” or “in other implementations” as used herein does not necessarily refer to a different implementation. It is intended, for example, that claimed subject matter includes combinations of exemplary embodiments or implementations in whole or in part.

In general, terminology may be understood at least in part from usage in context. For example, terms, such as “and” , “or” , or “and/or, ” as used herein may include a variety of meanings that may 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” or “at least one” as used herein, depending at least in part upon context, may be used to describe any feature, structure, or characteristic in a singular sense or may be used to describe combinations of features, structures or characteristics in a plural sense. Similarly, terms, such as “a” , “an” , or “the” , again, may be understood to convey a singular usage or to convey a plural usage, depending at least in part upon context. In addition, the term “based on” or “determined by” may be understood as not necessarily intended to convey an exclusive set of factors and may, instead, allow for existence of additional factors not necessarily expressly described, again, depending at least in part on context.

The wireless communications described herein may be through radio access including new radio (NR) access. Radio resource control (RRC) is a protocol layer between user equipment (UE) and the network (e.g. basestation or gNB) at the IP level (Network Layer) . There may be various Radio Resource Control (RRC) states, such as RRC connected (RRC_CONNECTED) , RRC inactive (RRC_INACTIVE) , and RRC idle (RRC_IDLE) state. As described, UE can transmit data through a Random Access Channel (RACH) protocol scheme or a Configured Grant (CG) scheme or grant scheme. The RACH scheme is merely one example of a protocol scheme for communications and other examples, including but not limited to CG, are possible. The RACH scheme may be used for the initial access process for setting up communications, including synchronization, of the UE and the basestation. FIGs. 1-2 show example radio access network (RAN) nodes (e.g. basestations) and user equipment and messaging environments. Initial access may refer to a process for the UE and the basestation to establish uplink synchronization. One example of this initial access may include Random Access Channel (RACH) process or protocol. This process may include obtaining an identification for radio access communication. RACH may include the first message from the UE to the basestation upon being powered on. RACH is a shared channel used by wireless terminals to access the mobile network (TDMA/FDMA, and CDMA based network) for call set-up and data transmission. Whenever a UE wants to make a MO (Mobile Originating) call it schedules the RACH. RACH is a transport-layer channel, while the corresponding physical- layer channel is PRACH. In some embodiments, RACH may be part of the initial access for communication between the UE and the network (e.g. basestation) . In some embodiments, there may be a timing advance (TA) update communication which may be after the initial access process.

In addition to providing uplink synchronization, RACH can also be used to obtain the resource for messaging (e.g. RRC Connection Request) . The timing between devices may be necessary for proper communication. Accordingly, there may be communications/updates for the timing between the UE and basestation is established for the communication. As described below in the embodiments, initial access may also include a time period ahead of downlink (DL) timing. Accordingly, the embodiments may apply this method to physical random access channel (PRACH) transmission. In some embodiments described below, PRACH transmission may also be used for a timing advance (TA) update which may not be considered initial access in some embodiments, where TA update is after the initial access. In other embodiments, initial access may include both PRACH transmission and TA update. The embodiments may enable an efficient PRACH design and system access, which may reduce PRACH overhead and efficiently support larger cell coverage.

FIG. 1 shows an example basestation 102. The basestation may also be referred to as a wireless network node. The basestation 102 may be further identified to as a nodeB (NB, e.g., an eNB or gNB) in a mobile telecommunications context. The example basestation may include radio Tx/Rx circuitry 113 to receive and transmit signaling with user equipment (UEs) 104. The basestation may also include network interface circuitry 116 to couple the basestation to the core network 110, e.g., optical or wireline interconnects, Ethernet, and/or other data transmission mediums/protocols.

The basestation may also include system circuitry 122. System circuitry 122 may include processor (s) 124 and/or memory 126. Memory 126 may include operations 128 and control parameters 130. Operations 128 may include instructions for execution on one or more of the processors 124 to support the functioning the basestation. For example, the operations may handle random access transmission requests from multiple UEs. The control parameters 130 may include parameters or support execution of the operations 128. For example, control parameters may include network protocol settings, random access messaging format rules, bandwidth parameters, radio frequency mapping assignments, and/or other parameters.

FIG. 2 shows an example random access messaging environment 200. In the random access messaging environment a UE 104 may communicate with a basestation 102 over a random access channel 252. In this example, the UE 104 supports one or more Subscriber Identity Modules (SIMs) , such as the SIM1 202. Electrical and physical interface 206 connects SIM1 202 to the rest of the user equipment hardware, for example, through the system bus 210.

The mobile device 200 includes communication interfaces 212, system logic 214, and a user interface 218. The system logic (system circuitry) 214 may include any combination of hardware, software, firmware, or other logic. The system logic 214 may be implemented, for example, with one or more systems on a chip (SoC) , application specific integrated circuits (ASIC) , discrete analog and digital circuits, and other circuitry. The system logic 214 is part of the implementation of any desired functionality in the UE 104. In that regard, the system logic 214 may include logic that facilitates, as examples, decoding and playing music and video, e.g., MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV decoding and playback; running applications; accepting user inputs; saving and retrieving application data; establishing, maintaining, and terminating cellular phone calls or data connections for, as one example, Internet connectivity; establishing, maintaining, and terminating wireless network connections, Bluetooth connections, or other connections; and displaying relevant information on the user interface 218. The user interface 218 and the inputs 228 may include a graphical user interface, touch sensitive display, haptic feedback or other haptic output, voice or facial recognition inputs, buttons, switches, speakers and other user interface elements. Additional examples of the inputs 228 include microphones, video and still image cameras, temperature sensors, vibration sensors, rotation and orientation sensors, headset and microphone input /output jacks, Universal Serial Bus (USB) connectors, memory card slots, radiation sensors (e.g., IR sensors) , and other types of inputs.

The system logic 214 may include one or more processors 216 and memories 220. The memory 220 stores, for example, control instructions 222 that the processor 216 executes to carry out desired functionality for the UE 104. The control parameters 224 provide and specify configuration and operating options for the control instructions 222. The memory 220 may also store any BT, WiFi, 3G, 4G, 5G or other data 226 that the UE 104 will send, or has received, through the communication interfaces 212. In various implementations, the system power may be supplied by a power storage device, such as a battery 282.

In the communication interfaces 212, Radio Frequency (RF) transmit (Tx) and receive (Rx) circuitry 230 handles transmission and reception of signals through one or more antennas 232. The communication interface 212 may include one or more transceivers. The transceivers may be wireless transceivers that include modulation /demodulation circuitry, digital to analog converters (DACs) , shaping tables, analog to digital converters (ADCs) , filters, waveform shapers, filters, pre-amplifiers, power amplifiers and/or other logic for transmitting and receiving through one or more antennas, or (for some devices) through a physical (e.g., wireline) medium.

The transmitted and received signals may adhere to any of a diverse array of formats, protocols, modulations (e.g., QPSK, 16-QAM, 64-QAM, or 256-QAM) , frequency channels, bit rates, and encodings. As one specific example, the communication interfaces 212 may include transceivers that support transmission and reception under the 2G, 3G, BT, WiFi, Universal Mobile Telecommunications System (UMTS) , High Speed Packet Access (HSPA) +, 4G /Long Term Evolution (LTE) , and 5G standards. The techniques described below, however, are applicable to other wireless communications technologies whether arising from the 3rd Generation Partnership Project (3GPP) , GSM Association, 3GPP2, IEEE, or other partnerships or standards bodies.

In wireless communication, initial access communication may be through different protocols. In one example, RACH is the initial access communication for setting up and synchronizing the communication between the basestation and the UE. As described below in the embodiments, initial access may also include a time period ahead of downlink (DL) timing. Accordingly, the embodiments may apply this method to physical random access channel (PRACH) transmission. In some embodiments described below, PRACH transmission may also be used for a timing advance (TA) update which may not be considered initial access in some embodiments, where TA update is after the initial access. In other embodiments, initial access may include both PRACH transmission and TA update.

FIG. 3 shows one embodiment of initial access signaling. The basestation determines a PRACH configuration. The configuration in block 302 may be generated as described below by the basestation. The UE can transmit an initial access signal to the basestation. The initial access signal could be sent when the UE is first powered on and is used for initializing and synchronizing the communication between that UE and the basestation. The initial access signal may utilize the established configuration for establishing the communication between the UE and the basestation in block 304. In other words, the configuration may be used for the initial access communication which is initiated in block 302. The configuration of the initial access is further described below. While the communication is described as initial access, RACH is one example of such communication and is described in examples below.

FIG. 4 shows an embodiment of a random access channel (RACH) preamble format 400. The initial access configuration 302 from FIG. 3 may include modifications or changes to the RACH preamble format 400. In some embodiments, the RACH preamble format 400 may include cyclic prefix (CP) 402, a preamble sequence 404, and/or a guard time (GT) 406. Further changes to the preamble are described below. The modified or configured RACH format, including the preamble may be referred to as an enhanced format or enhanced preamble.

FIG. 5 shows an embodiment of a physical random access channel (PRACH) timing. In a wireless communication system (e.g. 4G LTE or 5G NR system) , a Physical Random Access Channel (PRACH) may be based on cell coverage. PRACH is used by UEs to request an uplink allocation from the basestation. As shown in FIG. 5, the Cyclic Prefix (CP) and Guard Period (GP) cover the round trip delay of PRACH. Their length is at least 2R/c where R is cell radius (see e.g. FIGs. 6A-6B illustrating R) and c is the light speed (i.e. 3*108 m/s) . With multiple paths of radio channels, the CP and/or GP length may be 2R/c+ds where ds is a parameter for margin or delay spread of radio channel. GP may be generated by implementation and depend on coverage. In some embodiments, the ds parameter may be removed from GP. For larger cell coverage, the PRACH overhead may be increased. The embodiments described herein enable an efficient PRACH design and system access, which reduces PRACH overhead and efficiently supports larger cell coverage.

FIG. 6A shows an embodiment of positioning of user equipment (UE) relative to a basestation. The radius R illustrates a distance from a basestation. The basestation may indicate the cell range (e.g. ‘R = w meter’ ) and the number of areas in a cell (e.g. ‘N=3’ ) . In this example, the cell is divided into three areas (e.g. area n=0, 1, 2) based on the distance (d) to the basestation. The distance to the basestation in area n=0 is d<=R/3. The distance to the basestation in area n = 1 is R/3<=d<=2R/3. The distance to the basestation in area n = 2 is 2R/3<=d<=R. UE A, UE B, or UE C estimates which area it locates in and derives the area index n (i.e. n = 0, 1, 2 for UE A, UE B and UE C, respectively) . UE can send the area index it estimates to the basestation.

FIG. 6B shows another embodiment of positioning of user equipment (UE) relative to a basestation. This embodiment illustrates a non-uniform area division as compared with the area division in FIG. 6A, which had a uniform area division. In FIG. 6B, the area for n=1 is larger than the area for n=0. In other words, there are two different cell division strategies shown in FIG. 6A and FIG. 6B. For either strategy, the value of N (the number of area indices n) may be increased or decreased. As shown in FIG. 6A, the cell is divided into three areas (i.e. N=3) with the increment of R/3 for a uniform division. In some embodiments, the value of N can be larger or smaller and the distance d is adjusted accordingly. For the embodiment shown in FIG. 6B, two areas in the cell are used where d<=R/3 for area n=0 and R/3<=d<=R for area n=1. In some embodiments, the value of N can be larger or smaller and the distance d is adjusted accordingly.

FIG. 7 shows an embodiment of a timing diagram for a physical random access channel (PRACH) . This example is based on the embodiment shown in FIG. 6A where N=3. The starting position of PRACH is at the beginning of slot i. UE x (e.g. UE A, UE B, or UE C shown in FIG. 6A) will send PRACH at n*2R/ (3*c) ahead of a starting position of PRACH on the basis of DL timing. For example, the timing of sending the PRACH may be:

● UE A will send PRACH at time point t0 (illustrated in “DL timing zone for area 0” based on DL synch of UE A) which is the starting position of PRACH based on UE A’s DL timing (n=0 for UE A) . In other words, this is the beginning of slot i based on UE A’s DL timing;

● UE B will send PRACH at time point t1-2R/3C since the area index n for UE B is 1. The starting position of PRACH is “t1” based on UE B’s DL timing. This is the beginning of slot i based on UE B’s DL timing; and

● UE C will send PRACH at time point t2-4R/3C since the area index n for UE C is 2. The starting position of PRACH is “t2” based on UE C’s DL timing. This is the beginning of slot i based on UE C’s DL timing.

The CP length of PRACH may be determined by 2R/ (N*c) + ds where c is light speed (3*108 meter/second) and ds is a parameter indicated by the basestation. N is the total number of the areas (N=3 in this example) .

FIG. 8 shows another embodiment of a timing diagram for a physical random access channel (PRACH) . FIG. 8 is an alternative transmission timing diagram for an uplink signal other than PRACH. In this example, the uplink signal is Physical Uplink Shared Channel (PUSCH) , and is based on the embodiment shown in FIG. 6A where N=3. The transmission timing for PUSCH of UE A is t0-TA0, of UE B is t1- (TA1+2R/ (3*c) ) , and for UE C is t2- (TA2+4R/ (3*c) ) . TA0, TA1 and TA2 are the timing advance signals for UE A, UE B, and UE C respectively which are obtained via detection of PRACH by the basestation and sent to UE A, UE B, and UE C, respectively.

FIG. 9 shows an embodiment of frequency locations for a physical random access channel (PRACH) configuration. There may be two PRACH configurations (i.e. PRACH configuration0 and PRACH configuration1) , which includes PRACH format information and time, as well as frequency resource information. As shown in FIG. 9, the PRACH format for PRACH configuration0 is “PRACH format 0” and the corresponding PRACH is transmitted in slot1 and slot3. The frequency location for PRACH configuration0 is f1. The PRACH format for PRACH configuration1 is “PRACH format 1” and the corresponding PRACH is transmitted in slot2 and slot4. The frequency location for PRACH configuration0 is f2. The basestation broadcasts the two PRACH configurations and two values of N, i.e. N = 2 and N =3 corresponding to PRACH configuration1 and 0 respectively. In this example, N is the number of areas that one cell is divided into. The CP length of PRACH format in PRACH configuration 0 is less than that of PRACH format in PRACH configuration 1 as the former and latter one are associated to N = 3 and N=2, respectively. Accordingly, the UEs selecting PRACH configuration 0 have a higher location estimation capability (i.e. more precise estimation) than those selecting PRACH configuration1. In other words, a change in N changes the capability ability.

In embodiments described above, a formula was used to derive the transmission position of PRACH and other UL channels. In an alternative embodiment, the basestation may send different values without this formula calculation. Several X values may be indicated by basestation, where each X value corresponds to one RSRP range. UE measures RSRP and selects X value according to one X value according to its RSRP measurement and association between RSPPs and X values. In other words, the RSRP range may be used instead of area index n.

In another embodiment, the basestation may send the cell radius R to UE. In this embodiment, the basestation may over-estimate the size as compared with actual cell coverage (i.e. R is larger than actual cell coverage) . The UE measures Reference Signal Received Power (RSRP) and takes RSRP as well as the basestation’s transmission power indicated by basestation as an input to determine the area estimation, such as the value of “n. ” This input may be for an Artificial Intelligence (AI) or Machine-Learning (ML) algorithm for the area estimation. In an alternative embodiment, the basestation sends cell edge RSRP to UE. The UE measures RSRP and takes RSRP as well as cell edge RSRP as an input of the AI/ML algorithm to determine the area estimation result (i.e. value of area index n) .

FIG. 10 shows another embodiment of a timing diagram for a physical random access channel (PRACH) . This embodiment is similar to the embodiment shown in FIG. 7, except how the UE receives the timing values. In FIG. 7, the UE calculates the timing value with a formula, but in FIG. 10, the value is broadcast by basestation. In this embodiment, the basestation broadcasts three X values as a set (in the example of N=3, i.e. X0, X1 and X2, which correspond to n=0, 1 and 2 respectively) where X0 is assumed to be 0 in this embodiment. For the cell shown in FIG. 6A, the PRACH transmission position in FIG. 10 may include:

● UE A will send PRACH at time point t0-X0 which is the starting position of PRACH based on UE A’s DL timing (n=0 for UE A) . This is the beginning of slot i based on UE A’s DL timing.

● UE B will send PRACH at time point t1-X1 since the area index n for UE B is 1. The value of t1 is the starting position of PRACH based on UE B’s DL timing. This is the beginning of slot i based on UE B’s DL timing.

● UE C will send PRACH at time point t2-X2 since the area index n for UE C is 2. The value of t2 is the starting position of PRACH based on UE C’s DL timing. This is the beginning of slot i based on UE C’s DL timing.

In some embodiments, there may be more than one set of X values. For example, another set which comprise two X values, may be used in the case of N=2.

As described, UE sends PRACH to the basestation at the time point which is X seconds ahead of a starting position of PRACH on the basis of DL timing. In one embodiment, X = n*M where n is estimated area index and M is a time value. In one embodiment, M = 2R/ (N*C) , where R and N are indicated by the basestation, or M is indicated by the basestation, c is light speed. In some embodiments, one or several X values is indicated by the basestation. For example, each X value is associated to one RSRP range, or each X value is associated to one area index (i.e. ‘n’ ) .

In some embodiments, the UE uses a timing advance (TA) as TA + X, to be applied to a UL channel or signals where TA is indicated by the basestation.

In some embodiments, the UE sends an area index n to the basestation, or UE sends the X value it selected to basestation. The area index n may be estimated by UE with the parameters indicated by the basestation at least including R, RSRP, transmission power, and/or area division strategies (i.e. N) . The area index n or the X value may be sent via msg3 in PUSCH or preamble sequence of PRACH during random access procedure.

In some embodiments, the UE selects one PRACH configuration. Several PRACH configurations are broadcasted by the basestation, where each is associated to one area estimation capability. The PRACH configuration may indicate the PRACH format. The CP length of PRACH is obtained by leveraging parameters N, R and/or ds. The selection may be based on UE’s location estimation capability including whether or not area estimation is supported or based on the preciseness of area estimation. In other words, a larger N, or a higher preciseness may be used for selection. For example, N=1 may mean UE is incapable of area estimation.

In one embodiment, the UE estimates an area index via one or more of:

● the cell radius, the RSRP at cell edge, or the RSRP range for each area;

● the basestation's transmission power or PSD; or

● area division strategies (uniform/non-uniform with different values of N) .

In some embodiments, a UL channel or signal transmission may include: 1) the UE sending PRACH to the basestation at the time point which is X seconds ahead of a starting position of PRACH on the basis of DL timing, and/or 2) the UE taking TA + X as the timing advance applied to UL channel or signals. TA may be indicated by the basestation.

In one embodiment, the value of X may be X = n*M, wherein ‘n’ is an area index, which is estimated by UE by leveraging one or more following parameters:

● ‘R’ is cell range indication;

● RSRP is Reference Signal Receiving Power (e.g. the RSRP at cell edge) ;

● area division strategy, i.e. how a cell is divided into multiple area;

● ‘N’ is number of areas in a cell; or

● DL transmission power, or DL power spectrum density (PSD) .

As described, the UE may send the area index 'n' to the basestation. The area index ‘n’ may be sent in msg3 via PUSCH during random access procedure. The value of M may be M = 2R/ (N*C) where ‘R’ is cell range indication and ‘N’ is the number of areas in the cell. N and R are indicated by the basestation, or M is indicated by the basestation.

In some embodiments, one or several X values may be indicated by the basestation. Each X value is associated to one RSRP range or each X value is associated to one area index, i.e. ‘n’ . The UE may send the X value it selected to basestation. The X value may be sent via msg3 in PUSCH or preamble sequence of PRACH during random access procedure.

In some embodiments, the PRACH is based on one PRACH configuration. The PRACH configuration is selected by UE from several PRACH configurations indicated by the basestation. Each PRACH configuration is associated to one location estimation capability or one value of ‘N’ or one area division strategy. The PRACH configuration may indicate at least one of the following: PRACH format, time and/or frequency resources for PRACH. The CP length of PRACH is based on one or more the following parameters N, R and/or ds. The CP length = 2R/ (N*C) +ds or 2R/ (N*C) , or the CP length is equal to that of one PRACH format, which is closest to 2R/ (N*C) +ds or 2R/ (N*C) . The selection may be based on UE’s location estimation capability, whether or not area estimation is supported, or regardless of the preciseness of area estimation. This preciseness may be measured by the value of N (i.e. the larger the value of N is, the higher the preciseness is) . In other words, N=1 means UE is incapable of area estimation.

In some embodiments, the UE estimates the area index and utilizes the area index to send UL channel/signals. The UE estimates the area index ‘n’a nd sends the index to the basestation and/or uses the index to send uplink channels and/or signals. Alternatively, the UE selects an X value from a X value set indicated by the basestation and the UE sends the selected X value to basestation. Each X value may correspond to a RSRP range. There can be several X value sets indicated by the basestation. Each set corresponds to one cell division strategy (i.e. one N value) . The area index ‘n’ or the selected X value is sent in msg3 via PUSCH during a random access procedure. The index is estimated by UE by leveraging one or more following parameters:

● ‘R’ is cell range indication;

● RSRP is Reference Signal Receiving Power (e.g. the RSRP at cell edge) ;

● area division strategy, i.e. how a cell is divided into multiple area;

● ‘N’ is number of areas in a cell; or

● DL transmission power, or DL power spectrum density (PSD) .

The UE sends the PRACH to the basestation at the time point which is X seconds ahead of the starting position of PRACH on the basis of DL timing. The UE takes TA + X as the timing advance applied to UL channel or signals, where TA is indicated by the basestation, where X = n*M or one or several X values are indicated by the basestation. The value of M may be M = 2R/ (N*C) where ‘R’ is cell range indication and ‘N’ is the number of areas in the cell. N and R may be indicated by the basestation, or just M is indicated by the basestation.

In some embodiments, the PRACH is based on one PRACH configuration selected by UE from several PRACH configurations indicated by the basestation. Each PRACH configuration is associated to one location estimation capability or one value of ‘N’ or one area division strategy. The PRACH configuration may include at least one of the following: PRACH format, time and/or frequency resources for PRACH. The CP length of PRACH is based on one or more the following parameters N, R and/or ds. In some embodiments, CP length = 2R/ (N*C) +ds or 2R/ (N*C) . The CP length is equal to that of one PRACH format, which is closest to 2R/ (N*C) +ds or 2R/ (N*C) . The selection is based on UE’s location estimation capability, including whether or not area estimation is supported, or the preciseness of area estimation. The preciseness may be measured by the value of N (i.e. the larger the value of N is, the higher the preciseness is) . N=1 means UE is incapable of area estimation.

The system and process described above may be encoded in a signal bearing medium, a computer readable medium such as a memory, programmed within a device such as one or more integrated circuits, one or more processors or processed by a controller or a computer. That data may be analyzed in a computer system and used to generate a spectrum. If the methods are performed by software, the software may reside in a memory resident to or interfaced to a storage device, synchronizer, a communication interface, or non-volatile or volatile memory in communication with a transmitter. A circuit or electronic device designed to send data to another location. The memory may include an ordered listing of executable instructions for implementing logical functions. A logical function or any system element described may be implemented through optic circuitry, digital circuitry, through source code, through analog circuitry, through an analog source such as an analog electrical, audio, or video signal or a combination. The software may be embodied in any computer-readable or signal-bearing medium, for use by, or in connection with an instruction executable system, apparatus, or device. Such a system may include a computer-based system, a processor-containing system, or another system that may selectively fetch instructions from an instruction executable system, apparatus, or device that may also execute instructions.

A “computer-readable medium, ” “machine readable medium, ” “propagated-signal” medium, and/or “signal-bearing medium” may comprise any device that includes stores, communicates, propagates, or transports software for use by or in connection with an instruction executable system, apparatus, or device. The machine-readable medium may selectively be, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. A non-exhaustive list of examples of a machine-readable medium would include: an electrical connection “electronic” having one or more wires, a portable magnetic or optical disk, a volatile memory such as a Random Access Memory “RAM” , a Read-Only Memory “ROM” , an Erasable Programmable Read-Only Memory (EPROM or Flash memory) , or an optical fiber. A machine-readable medium may also include a tangible medium upon which software is printed, as the software may be electronically stored as an image or in another format (e.g., through an optical scan) , then compiled, and/or interpreted or otherwise processed. The processed medium may then be stored in a computer and/or machine memory.

The illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Additionally, the illustrations are merely representational and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive.

One or more embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the description.

The phrase "coupled with" is defined to mean directly connected to or indirectly connected through one or more intermediate components. Such intermediate components may include both hardware and software-based components. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional, different or fewer components may be provided.

The above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true spirit and scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description. While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.

Claims

A method for wireless communication, comprising:

sending a signal with a protocol a time period ahead of a downlink (DL) timing; and

applying a timing advance for uplink (UL) signals based on the time period.
The method of claim 1, wherein the time period is based on a location.
The method of claim 1, wherein the time period comprises X seconds, where X equals n*M, where n is an area index and M is a value for time.
The method of claim 3, wherein M = 2R/ (N*c) , where R is a cell range indication, N is a number of areas in a cell, and c is the speed of light.
The method of claim 3, wherein M is indicated by a basestation, the method further comprising:

receiving, from the basestation, a value for M.
The method of claim 3, wherein the sending is from a user equipment (UE) to a basestation, the method further comprising:

estimating n by the UE based on at least one of: R, reference signal receiving power (RSRP) , an area division strategy, N, or a DL transmission power.
The method of claim 3, further comprising:

sending n from the UE to the basestation.
The method of claim 7, wherein the sending from the UE to the basestation is via a Physical Uplink Shared Channel (PUSCH) during a random access procedure.
The method of claim 1, wherein a Cyclic Prefix (CP) length of a Physical Random Access Channel (PRACH) protocol is based on at least one of following parameters: N, R, and/or ds.
The method of claim 9, wherein the CP length equals at least one of the following: 2R/ (N*c) + ds or 2R/ (N*c) or the value close to 2R/ (N*c) + ds or 2R/ (N*c) .
The method of claim 1, wherein the time period is based on a reference signal receiving power (RSRP) range or the area index n.
The method of claim 11, wherein the time period is from a time period set which is indicated by a basestation, wherein each of the time period in the time period set corresponds to one RSRP range.
The method of claim 1, wherein the protocol comprises a Physical Random Access Channel (PRACH) protocol.
The method of claim 13, wherein the PRACH protocol is based on a PRACH configuration.
The method of claim 14, further comprising:

selecting the PRACH configuration from one of several indicated configurations.
The method of claim 15, wherein the PRACH configuration at least indicates a PRACH format, or time and/or frequency resources for the PRACH.
The method of claim 15, wherein the selecting is based on a location estimation capability of a user equipment (UE) .
The method of claim 1, wherein the sending is from a user equipment (UE) to a basestation and the applying is by the UE.
The method of claim 18, wherein the signal establishes communication between the UE and the basestation.
The method of claim 1, further comprising:

receiving, at the UE from the basestation, an indication of the timing advance; and

applying the timing advance to an uplink (UL) channel or signal.
The method of claim 20, further comprising:

sending the UL channel transmission.
A method for wireless communication, comprising:

selecting, by a user equipment (UE) a time period from a set of time periods; and

sending signals based on the selected time period.
The method of claim 22, wherein the time period set is indicated by the basestation and the UE sends a selected one of the time period from the time period set.
The method of claim 23, wherein the selected time period is sent in msg3 via PUSCH during a random access procedure.
The method of claim 22, wherein the time period is from a time period set which is indicated by a basestation, wherein each of the time periods in the time period set corresponds to one RSRP range.
The method of claim 22, further comprising:

sending a Physical Random Access Channel (PRACH) protocol to the basestation which is X seconds ahead of a starting position of PRACH based on a downlink (DL) timing.
The method of claim 26, wherein the PRACH protocol is based on a PRACH configuration selected by the UE from a set of PRACH configurations indicated by the basestation.
The method of claim 27, wherein the PRACH configuration at least indicates a PRACH format, or time and/or frequency resources for the PRACH.
The method of claim 22, wherein time period X is based on a reference signal receiving power (RSRP) range or the area index n.
The method of claim 22, wherein a Cyclic Prefix (CP) length of the PRACH is based on N, R, and/or ds.
The method of claim 30, wherein the CP length equals at least one of the following: 2R/ (N*c) + ds or 2R/ (N*c) or the value close to 2R/ (N*c) + ds or 2R/ (N*c) .
A method for wireless communication, comprising:

estimating an area index for sending uplink (UL) signals; and

sending signals based on the area index.
The method of claim 32, wherein the sending comprises sending the area index.
The method of claim 32, wherein the sending is from a user equipment (UE) to a basestation via a Physical Uplink Shared Channel (PUSCH) during a random access procedure.
The method of claim 32, further comprising:

sending a signal with protocol a time period ahead of a downlink (DL) timing; and

applying a timing advance for uplink (UL) signals based on the time period.
The method of claim 35, wherein the protocol comprises a Physical Random Access Channel (PRACH) protocol that is based on a PRACH configuration.
The method of claim 32, wherein the time period comprises X seconds, where X equals n*M, where n is an area index and M is a value for time.
The method of claim 37, wherein M = 2R/ (N*c) , where R is a cell range indication, N is a number of areas in a cell, and c is the speed of light.
The method of claim 37, wherein M is indicated by the basestation, the method further comprising:

receiving, from the basestation, a value for M.
The method of claim 32, further comprising:

estimating area index by the UE based on at least one of: R, reference signal receiving power (RSRP) , an area division strategy, N, or a DL transmission power.
The method of claim 32, further comprising:

sending area index from the UE to the basestation.
A method for wireless communication comprising:

indicating one or more Physical Random Access Channel (PRACH) protocol configurations; and

indicating one or more sets of time periods or one or more cell division strategies, wherein each of the PRACH protocol configurations are associated with one set of time periods or associated with one cell division strategy.
The method of claim 42, wherein one time period from the set of time periods corresponds to a reference signal receiving power (RSRP) range.
The method of claim 42, wherein each of the cell division strategies refers to how many areas the cell is divided into.
The method of claim 42, wherein the cell is divided uniformly or non-uniformly.
The method of claim 44, further comprising:

receiving an area index n or time period.
The method of claim 46, wherein the index is estimated by a user equipment (UE) by leveraging one or more of: a cell range (R) , reference signal receiving power (RSRP) , an area division strategy, a number of areas in a cell (N) , or a downlink (DL) transmission power.
The method of claim 42, wherein the time period corresponds to an RSRP range.
The method of claim 42, further comprising:

receiving a PRACH, which corresponds to one of the PRACH protocol configurations.
The method of claim 49, wherein a Cyclic Prefix (CP) length of the PRACH is based on at least one of following parameters: a number of areas in a cell (N) , a cell range (R) , and/or ds.
The method of claim 50, wherein the CP length equals at least one of the following: 2R/ (N*c) + ds or 2R/ (N*c) or the value close to 2R/ (N*c) + ds or 2R/ (N*c) .
A wireless communications apparatus comprising a processor and a memory, wherein the processor is configured to read code from the memory and implement a method recited in any of claims 1 to 51.
A computer program product comprising a computer-readable program medium code stored thereupon, the code, when executed by a processor, causing the processor to implement a method recited in any of claims 1 to 51.