WO2018053255A1

WO2018053255A1 - Variable random-access channel resource configuration

Info

Publication number: WO2018053255A1
Application number: PCT/US2017/051766
Authority: WO
Inventors: Seunghee Han; Gregory Vladimirovich Morozov; Wook Bong Lee; Daewon Lee; Alexei Vladimirovich Davydov
Original assignee: Intel IP Corporation
Priority date: 2016-09-15
Filing date: 2017-09-15
Publication date: 2018-03-22

Abstract

A radio access system includes a base station (BS) configurable for facilitating multiple coverage areas in a cell. The BS is to store, in its memory, allocations of different amounts of physical random access channel (PRACH) resources in association with different ones of the multiple coverage areas. The BS is to initiate informational broadcasting that includes coverage area-specific PRACH resource configuration parameters, and to initiate monitoring of the different amounts of PRACH resources in the different ones of the multiple coverage areas. In response to receipt of a random-access preamble from a user equipment (UE) device on any PRACH resource, the BS is to initiate a random-access connection protocol with that UE device.

Description

VARIABLE RANDOM- ACCESS CHANNEL

RESOURCE CONFIGURATION

PRIOR APPLICATIONS

[0001] This Application claims the benefit of U.S. Provisional Applications No. 62/395,236 filed September 15, 2016 and 62/418,536 filed November 7, 2016, the disclosures of which are incorporated by reference herein.

TECHNICAL FIELD

[0002] Embodiments pertain to wireless communications. Some embodiments relate to wireless networks including 3 GPP (Third Generation Partnership Project) networks, 3 GPP LTE (Long Term Evolution) networks, 3 GPP LTE-A (LTE Advanced) networks, and fifth-generation (5G) networks. Other embodiments relate to Wi-Fi wireless local area networks (WLANs). Further embodiments are more generally applicable outside the purview of LTE and Wi- Fi networks. Aspects of the embodiments are directed to utilizing multiple coverage areas within a cell, including configuring random-access channel parameters, variable transmit power, and selection of coverage areas.

BACKGROUND

[0003] There is an ongoing need to increase mobile network capacity. Recent developments utilize higher-frequency radio bands. Millimeter-wave

communications, for example, use radio frequencies in the range of 30-300 GHz to provide colossal bandwidth by today's standards - on the order of 20 Gb/s, for example. The propagation characteristics of millimeter-wave radio signals differ considerably from more familiar radio signals in the 2-5 GHz range. For one, their range is significantly limited by comparison due to attenuation in the atmosphere. In addition, millimeter-wave signals experience reflections, refractions, and scattering due to walls, buildings and other objects to a much greater extent than lower-frequency signals. These physical challenges also present some useful opportunities for communication system designers. For example, the limited range of millimeter-wave transmissions make them suitable for resource-element (time slot and frequency) reuse in high-density

deployments in city blocks, office buildings, schools, stadiums, and the like, where there may be a large plurality of user equipment devices. In addition, the potential for precise directionality control provides opportunity to make extensive use of multi-user multiple input/multiple output (MU-MEVIO) techniques. Solutions are needed to make practical use of these opportunities in highly-directional wireless networks.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components.

Some embodiments are illustrated by way of example, and not limitation, in the following figures of the accompanying drawings.

[0005] FIG. 1 is a functional diagram of a 3GPP network in accordance with some embodiments.

[0006] FIG. 2 is a functional diagram of a user device 200, also referred to as user equipment (UE) in accordance with some embodiments.

[0007] FIG. 3 illustrates a base station or infrastructure equipment radio head in accordance with an example.

[0008] FIG. 4 illustrates an exemplary millimeter wave communication circuitry according to some aspects.

[0009] FIG. 5 illustrates protocol functions that may be implemented in a wireless communication device according to some aspects.

[0010] FIG. 6 illustrates protocol entities that may be implemented in wireless communication devices according to some examples.

[0011] FIG. 7 is a diagram illustrating an exemplary communication network scenario in an aspect of this disclosure.

[0012] FIG. 8 is a simplified protocol diagram illustrating BS and UE operations making use of a physical random access channel (PRACH) for initial UE boot-up according to some examples.

[0013] FIGs. 9A-9C are diagrams illustrating various examples of PRACH resource allocations that may be performed by a base station according to some embodiments. [0014] FIG. 10 is a flow diagram illustrating operations that may be performed by a base station to facilitate multiple coverage areas within the cell, in accordance with some embodiments.

[0015] FIG. 11 is a flow diagram illustrating operations that may be performed by a user device operating in a cell having multiple coverage areas to facilitate selection of a coverage area through which to connect to the base station serving the cell, according to some embodiments.

DETAILED DESCRIPTION

[0016] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. A number of examples are described in the context of 3 GPP communication systems and components thereof. It will be understood that principles of the embodiments are applicable in other types of communication systems, such as Wi-Fi or Wi-Max networks, Bluetooth or other personal-area networks (PANs), Zigbee or other home-area networks (HANs), wireless mesh networks, and the like, without limitation, unless expressly limited by a corresponding claim.

[0017] Given the benefit of the present disclosure, persons skilled in the relevant technologies will be able to engineer suitable variations to implement principles of the embodiments in other types of communication systems. For example, it will be understood that a base station of a 3GPP context is analogous, generally speaking, to a wireless access point (AP) of a WLAN context. Likewise, user equipment (UE) of a 3 GPP context is generally analogous to mobile stations (ST As) of WLANs. Various diverse embodiments may incorporate structural, logical, electrical, process, and other differences. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all presently-known, and after-arising, equivalents of those claims.

[0018] Practical deployments of cellular base stations, such as those used in evolved node B (eNB) and new-radio node B (gNB) installations, support multiple coverage areas, such as coverage areas corresponding to different beam directions, coverage areas corresponding to different transmission/reception points (TRPs), or to coverage areas corresponding to combinations of beam directions and TRPs. For a given base station, the various coverage areas may have differing user load tendencies. For example, coverage areas may vary in size due to beam dispersion, varying transmit power for different TRPs, varying topography or obstructions, or varying population densities.

[0019] Additionally, due to non-uniform distribution of the UEs within the cell, the probability of UEs selecting different beams may vary. As a result, the probability of collisions over different physical random access channel resources may vary commensurately. For example, the RACH resources associated with beams more frequently used by the UEs are likely to have higher collision probability than RACH resources associated with beams less frequently selected by the UEs.

[0020] Various aspects of the embodiments are directed to improving access to base stations using physical random access channel (PRACH) resources taking into account the differences between user equipment (UE) demand in the different coverage areas facilitated by a base station (BS). In some examples, PRACH resources are allocated non-uniformly among the various coverage areas within a cell. In a related embodiment, the allocation of the PRACH resources among the coverage areas of a BS corresponds to the relative UE loading in those coverage areas.

[0021] For instance, based on the share of the UE loading, each coverage area may be allocated a proportional share of the PRACH resources. The PRACH resource allocation may be dynamically varied in response to measured variations of UE loading.

[0022] PRACH resource allocation may be defined in terms of temporal presence, spectral presence, spatial presence, some combination of any two these presence types, or as a combination of all three types of presence. For instance, spatial-presence allocation may be defined in terms of subcarriers or other bandwidth unit occupied by allocated PRACH resources; temporal-presence allocation of the PRACH resources may be defined in terms of subframes or other time-duration unit occupied by PRACH resources; and spatial-presence allocation may be defined in terms of UE power offset or other measure of transmission range, to be associated with certain PRACH resources.

[0023] In related embodiments, a beam synchronization signal (BSS) may have its signal identity be associated with one or more PRACH resources at the base station. In turn, each UE receiving the BSS may determine one or more PRACH resources and associated random-access preamble transmission parameters based on the BSS.

[0024] Upon determining the available PRACH resources, a UE may select a suitable PRACH resource on which to transmit a random-access preamble. The selection may be according to received higher-layer PRACH resource parameters.

[0025] In another embodiment, PRACH resources that are associated with different coverage areas may be further associated with different transmit power levels (e.g., represented as power-offset values) that are communicated to UEs along with the PRACH resource information. In turn, UEs may use the transmit power level information to determine the transmit power used by the particular coverage area in which the UE receives the PRACH resources. Accordingly, the UEs may determine the path loss and apply suitable adjustments to their uplink transmit power level.

[0026] In related embodiments, UEs that may receive PRACH resources and transmit power level information from multiple coverage areas may execute a decision process to select a preferred coverage area with which to connect to the base station. For instance, a UE may select a coverage area associated with a lower transmit power so that ensuing data communications may be more energy efficient.

[0027] In a related example, the BS may vary the transmit power level information communicated along with the PRACH information, over time in response to UE loading or other situational trends.

[0028] In a related aspect, each coverage area within a cell served by a BS may be associated with a particular type of PRACH preamble to be used by UEs as they send random access (RA) preambles. Accordingly, on receipt of a particular RA preamble, the BS may know which of the coverage areas the UE wishes to utilize, and executes the remainder of the RA protocol

commensurately.

[0029] FIG. 1 is a functional diagram of a 3GPP network in accordance with some embodiments. The network comprises a radio access network (RAN) (e.g., as depicted, the E-UTRAN or evolved universal terrestrial radio access network) 101 and the core network 120 (e.g., shown as an evolved packet core (EPC)) coupled together through an SI interface 115. For convenience and brevity sake, only a portion of the core network 120, as well as the RAN 101, is shown.

[0030] The core network 120 includes a mobility management entity (MME) 122, a serving gateway (serving GW) 124, and packet data network gateway (PDN GW) 126. The RAN 101 includes one or more base stations, such as evolved Node-B (eNB) 104, new-radio Node Bs (gNB) 106, or the like, for communicating with user equipment (UE) 102. Hereinafter, the terms eNB, gNB, and base station (BS) may be used interchangeably unless a specific distinction is intended, in which case the distinction will be specifically pointed out. The BSs 104, 106 may include macro eNBs and low power (LP) eNBs. In accordance with some embodiments, the BSs 104, 106 may transmit a downlink control message to the UE 102 to indicate an allocation of physical uplink control channel (PUCCH) channel resources. The UE 102 may receive the downlink control message from the BSs 104, 106, and may transmit an uplink control message to the BSs 104, 106 in at least a portion of the PUCCH channel resources. These embodiments will be described in more detail below.

[0031] The MME 122 is similar in function to the control plane of legacy Serving GPRS Support Nodes (SGSN). The MME 122 manages mobility aspects in access such as gateway selection and tracking area list management. The serving GW 124 terminates the interface toward the RAN 101, and routes data packets between the RAN 101 and the core network 120. In addition, it may be a local mobility anchor point for inter-eNB handoffs and also may provide an anchor for inter-3GPP mobility. Other responsibilities may include lawful intercept, charging, and some policy enforcement. The serving GW 124 and the MME 122 may be implemented in one physical node or separate physical nodes. The PDN GW 126 terminates a SGi interface toward the packet data network (PDN). The PDN GW 126 routes data packets between the EPC 120 and the external PDN, and may be a key node for policy enforcement and charging data collection. It may also provide an anchor point for mobility with non-LTE accesses. The external PDN can be any kind of IP network, as well as an IP

Multimedia Subsystem (IMS) domain. The PDN GW 126 and the serving GW 124 may be implemented in one physical node or separated physical nodes.

[0032] The BSs 104, 106 (macro and micro) terminate the air interface protocol and may be the first point of contact for a UE 102. In some embodiments, a BS 104, 106 may fulfill various logical functions for the RAN 101 including but not limited to RNC (radio network controller functions) such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management. In accordance with embodiments, UE 102 may be configured to communicate with a BS 104, 106 over a multipath fading channel in accordance with an Orthogonal Frequency Division Multiple Access (OFDMA) communication technique. The OFDM signals may comprise a plurality of orthogonal subcarriers.

[0033] The SI interface 115 is the interface that separates the RAN 101 and the EPC 120. It is split into two parts: the Sl-U, which carries traffic data between the BSs 104, 106 and the serving GW 124, and the Sl-MME, which is a signaling interface between the BS 104, 106 and the MME 122. The X2 interface is the interface between BS 104, 106. The X2 interface comprises two parts, the X2-C and X2-U. The X2-C is the control plane interface between the BS 104, 106, while the X2-U is the user plane interface between the BSs 104, 106.

[0034] With cellular networks, LP cells are typically used to extend coverage to indoor areas where outdoor signals do not reach well, or to add network capacity in areas with very dense phone usage, such as train stations. As used herein, the term low power (LP) eNB or gNB refers to any suitable relatively low power eNB or gNB for implementing a narrower cell (narrower than a macro cell) such as a femtocell, a picocell, or a micro cell. Femtocell eNBs or gNBs are typically provided by a mobile network operator to its residential or enterprise customers. A femtocell is typically the size of a residential gateway or smaller and generally connects to the user's broadband line. Once plugged in, the femtocell connects to the mobile operator's mobile network and provides extra coverage in a range of typically 30 to 50 meters for residential femtocells. Thus, a LP eNB or gNB might be a femtocell eNB or gNB since it is coupled through the PDN GW 126. Similarly, a picocell is a wireless communication system typically covering a small area, such as in-building (offices, shopping malls, train stations, etc.), or more recently in-aircraft. A picocell eNB or gNB can generally connect through the X2 link to another eNB or gNB such as a macro eNB or gNB through its base station controller (BSC) functionality. Thus, LP eNB or gNB may be implemented with a picocell since it is coupled to a macro eNB via an X2 interface. Picocells or other LP BSs may incorporate some or all functionality of a macro BS. In some cases, this may be referred to as an access point base station or enterprise femtocell.

[0035] In some embodiments, a downlink resource grid may be used for downlink transmissions from a BS 104, 106 to a UE 102, while uplink transmission from the UE 102 to the BS 104, 106 may utilize similar techniques. The grid may be a time-frequency grid, called a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot. Such a time-frequency plane representation is a common practice for OFDM systems, which makes it intuitive for radio resource allocation. Each column and each row of the resource grid correspond to one OFDM symbol and one OFDM

subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one slot in a radio frame. The smallest time-frequency unit in a resource grid is denoted as a resource element (RE). Each resource grid comprises a number of resource blocks (RBs), which describe the mapping of certain physical channels to resource elements. Each resource block comprises a collection of resource elements in the frequency domain and may represent the smallest quanta of resources that currently can be allocated. There are several different physical downlink channels that are conveyed using such resource blocks. With particular relevance to this disclosure, two of these physical downlink channels are the physical downlink shared channel and the physical down link control channel.

[0036] The physical downlink shared channel (PDSCH) carries user data and higher-layer signaling to a UE 102 (FIG. 1). The physical downlink control channel (PDCCH) carries information about the transport format and resource allocations related to the PDSCH channel, among other things. It also informs the UE 102 about the transport format, resource allocation, and hybrid automatic repeat request (HARQ) information related to the uplink shared channel.

Typically, downlink scheduling (e.g., assigning control and shared channel resource blocks to UE 102 within a cell) may be performed at the BS 104, 106 based on channel quality information fed back from the UE 102 to the BS 104, 106, and then the downlink resource assignment information may be sent to the UE 102 on the control channel (PDCCH) used for (assigned to) the UE 102.

[0037] The PDCCH uses CCEs (control channel elements) to convey the control information. Before being mapped to resource elements, the PDCCH complex-valued symbols are first organized into quadruplets, which are then permuted using a sub-block inter-leaver for rate matching. Each PDCCH is transmitted using one or more of these control channel elements (CCEs), where each CCE corresponds to nine sets of four physical resource elements known as resource element groups (REGs). Four QPSK symbols are mapped to each REG. The PDCCH can be transmitted using one or more CCEs, depending on the size of downlink control information (DCI) and the channel condition. There may be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation level, L=l, 2, 4, or 8).

[0038] As used herein, the term circuitry may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), or memory (shared, dedicated, or group) that executes one or more software or firmware programs, a combinational logic circuit, or other suitable hardware components that provide

the described functionality. In some embodiments, the circuitry may be implemented in, or functions associated with the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, circuitry may include logic, at least partially operable in hardware. Embodiments described herein may be implemented into a system using any suitably configured hardware or software.

[0039] FIG. 2 is a functional diagram of a user device 200, also referred to as user equipment (UE) in accordance with some embodiments. The UE 200 may be a mobile device in some aspects and includes an application processor 205, baseband processor 210 (also referred to as a baseband module), radio front end module (RFEM) 215, memory 220, connectivity module 225, near field communication (NFC) controller 230, audio driver 235, camera driver 240, touch screen 245, display driver 250, sensors 255, removable memory 260, power management integrated circuit (PMIC) 265 and smart battery 270.

[0040] In some aspects, application processor 205 may include, for example, one or more CPU cores and one or more of cache memory, low drop-out voltage regulators (LDOs), interrupt controllers, serial interfaces such as serial peripheral interface (SPI), inter-integrated circuit (I2C) or universal programmable serial interface module, real time clock (RTC), timer-counters including interval and watchdog timers, general purpose input-output (IO), memory card controllers such as secure digital / multi-media card (SD/MMC) or similar, universal serial bus (USB) interfaces, mobile industry processor interface (MTPI) interfaces and Joint Test Access Group (JTAG) test access ports.

[0041] In some aspects, baseband module 210 may be implemented, for example, as a solder-down substrate including one or more integrated circuits, a single packaged integrated circuit soldered to a main circuit board, and/or a multi-chip module containing two or more integrated circuits.

[0042] FIG. 3 illustrates a base station or infrastructure equipment radio head 300 in accordance with an example. The base station radio head 300 may include one or more of application processor 305, baseband modules 310, one or more radio front end modules 315, memory 320, power management circuitry 325, power tee circuitry 330, network controller 335, network interface connector 340, satellite navigation receiver module 345, and user interface 350.

[0043] In some aspects, application processor 305 may include one or more CPU cores and one or more of cache memory, low drop-out voltage regulators (LDOs), interrupt controllers, serial interfaces such as SPI, I2C or universal programmable serial interface module, real time clock (RTC), timer-counters including interval and watchdog timers, general purpose IO, memory card controllers such as SD/MMC or similar, USB interfaces, MIPI interfaces and Joint Test Access Group (JTAG) test access ports.

[0044] In some aspects, baseband processor 310 may be implemented, for example, as a solder-down substrate including one or more integrated circuits, a single packaged integrated circuit soldered to a main circuit board or a multi- chip module containing two or more integrated circuits.

[0045] In some aspects, memory 320 may include one or more of volatile memory including dynamic random access memory (DRAM) and/or

synchronous dynamic random access memory (SDRAM), and nonvolatile memory (NVM) including high-speed electrically erasable memory (commonly referred to as Flash memory), phase change random access memory (PRAM), magnetoresi stive random access memory (MRAM) and/or a three-dimensional crosspoint memory. Memory 320 may be implemented as one or more of solder down packaged integrated circuits, socketed memory modules and plug-in memory cards. [0046] In some aspects, power management integrated circuitry 325 may include one or more of voltage regulators, surge protectors, power alarm detection circuitry and one or more backup power sources such as a battery or capacitor. Power alarm detection circuitry may detect one or more of brown out (under-voltage) and surge (over-voltage) conditions.

[0047] In some aspects, power tee circuitry 330 may provide for electrical power drawn from a network cable to provide both power supply and data connectivity to the base station radio head 300 using a single cable.

[0048] In some aspects, network controller 335 may provide connectivity to a network using a standard network interface protocol such as Ethernet. Network connectivity may be provided using a physical connection which is one of electrical (commonly referred to as copper interconnect), optical or wireless.

[0049] In some aspects, satellite navigation receiver module 345 may include circuitry to receive and decode signals transmitted by one or more navigation satellite constellations such as the global positioning system (GPS), Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS), Galileo and/or BeiDou. The receiver 345 may provide data to application processor 305 which may include one or more of position data or time data. Application processor 305 may use time data to synchronize operations with other radio base stations.

[0050] In some aspects, user interface 350 may include one or more of physical or virtual buttons, such as a reset button, one or more indicators such as light emitting diodes (LEDs) and a display screen.

[0051] FIG. 4 illustrates an exemplary millimeter wave communication circuitry 400 according to some aspects. Circuitry 400 is alternatively grouped according to functions. Components as shown in FIG. 4 are shown here for illustrative purposes and may include other components not shown.

[0052] Millimeter wave communication circuitry 400 may include protocol processing circuitry 405, which may implement one or more of medium access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), radio resource control (RRC) and non-access stratum (NAS) functions. Protocol processing circuitry 405 may include one or more processing cores (not shown) to execute instructions and one or more memory structures (not shown) to store program and data information. [0053] Millimeter wave communication circuitry 400 may further include digital baseband circuitry 410, which may implement physical layer (PHY) functions including one or more of hybrid automatic repeat request (HARQ) functions, scrambling and/or descrambling, coding and/or decoding, layer mapping and/or de-mapping, modulation symbol mapping, received symbol and/or bit metric determination, multi-antenna port pre-coding and/or decoding which may include one or more of space-time, space-frequency or spatial coding, reference signal generation and/or detection, preamble sequence generation and/or decoding, synchronization sequence generation and/or detection, control channel signal blind decoding, and other related functions.

[0054] Millimeter wave communication circuitry 400 may further include transmit circuitry 415, receive circuitry 420 and/or antenna array circuitry 430.

[0055] Millimeter wave communication circuitry 400 may further include radio frequency (RF) circuitry 425. In an aspect of the invention, RF circuitry 425 may include multiple parallel RF chains for one or more of transmit or receive functions, each connected to one or more antennas of the antenna array 430.

[0056] In an aspect of the disclosure, protocol processing circuitry 405 may include one or more instances of control circuitry (not shown) to provide control functions for one or more of digital baseband circuitry 410, transmit circuitry 415, receive circuitry 420, and/or radio frequency circuitry 425.

[0057] An illustration of protocol functions that may be implemented in a wireless communication device according to some aspects is illustrated in FIG. 5.

[0058] In some aspects, protocol layers may include one or more of physical layer (PHY) 510, medium access control layer (MAC) 520, radio link control layer (RLC) 530, packet data convergence protocol layer (PDCP) 540, service data adaptation protocol (SDAP) layer 547, radio resource control layer (RRC) 555, and non-access stratum (NAS) layer 557, in addition to other higher layer functions not illustrated.

[0059] According to some aspects, protocol layers may include one or more service access points that may provide communication between two or more protocol layers. [0060] According to some aspects, PHY 510 may transmit and receive physical layer signals 505 that may be received or transmitted respectively by one or more other communication devices. According to some aspects, physical layer signals 505 may comprise one or more physical channels.

[0061] According to some aspects, an instance of PHY 510 may process requests from and provide indications to an instance of MAC 520 via one or more physical layer service access points (PHY-SAP) 515. According to some aspects, requests and indications communicated via PHY-SAP 515 may comprise one or more transport channels.

[0062] According to some aspects, an instance of MAC 510 may process requests from and provide indications to an instance of RLC 530 via one or more medium access control service access points (MAC-SAP) 525. According to some aspects, requests and indications communicated via MAC-SAP 525 may comprise one or more logical channels.

[0063] According to some aspects, an instance of RLC 530 may process requests from and provide indications to an instance of PDCP 540 via one or more radio link control service access points (RLC-SAP) 535. According to some aspects, requests and indications communicated via RLC-SAP 535 may comprise one or more RLC channels.

[0064] According to some aspects, an instance of PDCP 540 may process requests from and provide indications to one or more of an instance of RRC 555 and one or more instances of SDAP 547 via one or more packet data

convergence protocol service access points (PDCP-SAP) 545. According to some aspects, requests and indications communicated via PDCP-SAP 545 may comprise one or more radio bearers.

[0065] According to some aspects, an instance of SDAP 547 may process requests from and provide indications to one or more higher layer protocol entities via one or more service data adaptation protocol service access points (SDAP-SAP) 549. According to some aspects, requests and indications communicated via SDAP-SAP 549 may comprise one or more quality of service (QoS) flows.

[0066] According to some aspects, RRC entity 555 may configure, via one or more management service access points (M-SAP), aspects of one or more protocol layers, which may include one or more instances of PHY 510, MAC 520, RLC 530, PDCP 540 and SDAP 547. According to some aspects, an instance of RRC 555 may process requests from and provide indications to one or more NAS entities via one or more RRC service access points (RRC-SAP) 556.

[0067] FIG. 6 illustrates protocol entities that may be implemented in wireless communication devices according to some examples. Wireless communication devices in these examples may include one or more of a user equipment (UE) 660, a BS, which may be termed an evolved node B (eNB), or new radio node B (gNB) 680, and a network function, which may be termed a mobility

management entity (MME), or an access and mobility management function (AMF) 694, according to some aspects.

[0068] According to some aspects, gNB 680 may be implemented as one or more of a dedicated physical device such as a macro-cell, a femto-cell or other suitable device, or in an alternative aspect, may be implemented as one or more software entities running on server computers as part of a virtual network termed a cloud radio access network (CRAN).

[0069] According to some aspects, one or more protocol entities that may be implemented in one or more of UE 660, gNB 680 and AMF 694, may be described as implementing all or part of a protocol stack in which the layers are considered to be ordered from lowest to highest in the order PHY, MAC, RLC, PDCP, RRC and NAS. According to some aspects, one or more protocol entities that may be implemented in one or more of UE 660, gNB 680 and AMF 694, may communicate with a respective peer protocol entity that may be

implemented on another device, using the services of respective lower layer protocol entities to perform such communication.

[0070] According to some aspects, UE PHY 672 and peer entity gNB PHY 690 may communicate using signals transmitted and received via a wireless medium. According to some aspects, UE MAC 670 and peer entity gNB MAC 688 may communicate using the services provided respectively by UE PHY 672 and gNB PHY 690. According to some aspects, UE RLC 668 and peer entity gNB RLC 686 may communicate using the services provided respectively by UE MAC 670 and gNB MAC 688. According to some aspects, UE PDCP 666 and peer entity gNB PDCP 684 may communicate using the services provided respectively by UE RLC 668 and 5 GNB RLC 686. According to some aspects, UE RRC 664 and gNB RRC 682 may communicate using the services provided respectively by UE PDCP 666 and gNB PDCP 684. According to some aspects, UE NAS 662 and AMF NAS 692 may communicate using the services provided respectively by UE RRC 664 and gNB RRC 682.

[0071] Examples, as described herein, may include, or may operate on, logic or a number of components, engines, modules, or circuitry which for the sake of consistency are termed modules, although it will be understood that these terms may be used interchangeably. Modules may be hardware, software, or firmware communicatively coupled to one or more processors in order to carry out the operations described herein. Modules may be hardware modules, and as such modules may be considered tangible entities capable of performing specified operations and may be configured or arranged in a certain manner. In an example, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. In an example, the whole or part of one or more hardware processors may be configured by firmware or software (e.g., instructions, an application portion, or an application) as a module that operates to perform specified operations. In an example, the software may reside on a machine-readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations. Accordingly, the term hardware module is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein.

[0072] Considering examples in which modules are temporarily configured, each of the modules need not be instantiated at any one moment in time. For example, where the modules comprise a general-purpose hardware processor core configured using software; the general-purpose hardware processor core may be configured as respective different modules at different times. Software may accordingly configure a hardware processor core, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time.

[0073] FIG. 7 is a diagram illustrating an exemplary communication network scenario in an aspect of this disclosure. As depicted, communication network scenario 700 is exemplary in nature simplified for purposes of this explanation. Cell 710 is facilitated by a multi -coverage-area base station 712, which includes transmission reception points (TRPs) 720, TRPs 722, and BS processing circuitry 714. Each set of TRPs 720, 722 is communicatively coupled with BS processing circuitry via interconnects 716 and 716, respectively. Each set of TRPs 720, 722 may provide one or more coverage areas within cell 710. For instance, as depicted, coverage areas 740A and 742A are provided by TRPs 720, and coverage area 744A is provided by TRPs 722.

[0074] The various coverage areas may be provided by geographically- distributed TRPs to ensure sufficient coverage in portions of the cell 710 that may be obstructed from a primary TRP by a building, as exemplified at 760, terrain, or other feature. In related examples, TRPs may be positioned on towers, as depicted in FIG. 7, on buildings or other structures, or indoors to provide coverage in those spaces.

[0075] Multiple TRPs may be clustered together, or may be individually distributed. TRPs may include active antenna elements, or passive antenna elements. Passive antenna elements connect via a RF-signal cable to RF transmission and reception circuitry that is situated remotely from the radiating elements at processing circuitry 714. Active antenna elements include radio circuitry situated locally with the radiating elements (e.g., on the towers), and may connect with remotely-located baseband or application processing circuitry at 714.

[0076] As an example, each TRP from among TRPs 720, 722 may utilize hybrid beamforming, in which there are N antenna ports (n= 1, 2, ... , N) at the base station and each antenna port is connected to a subarray of M antenna elements (m= 1, 2, ... , M). Each antenna element has a phase shifter controlled by the analog beamforming parameters, such as beamforming weights. In this respect, each antenna port is connected to a phased array of antenna elements in which the relative phases of the respective signals feeding the antenna elements are set in such a way that each antenna port's effective beamforming radiation pattern is reinforced in a desired direction and suppressed in undesired directions.

[0077] Broadside 750 is a reference axis from which beam directions (i.e., angles) in relation to the base station are defined. TRPs 720 provide coverage area 740A situated predominantly along beam direction 740B at angle -θ«, and coverage area 742A situated along beam direction 742B at angle Q_m- As depicted, coverage area 740A is larger than coverage area 742A. This difference in coverage area size may be attributable to different transmit power levels used by BS 712 for the different beam directions 740B, 742B. The coverage area size may also vary based on different elevational angles for different beams, as where a steeper elevational beam angle of a transmission from a tower or high-mounted TRP would tend to illuminate a smaller area on the ground, and shallower elevational angle would tend to illuminate a larger area on the ground. As depicted in example scenario 700, UE 730 may connect to BS 712 in coverage area 740 A, and UE 732 may connect in coverage area 742 A.

[0078] TRPs 722 provide coverage area 744A, which in this example is shown as a generally omnidirectional coverage area in which UEs 734 and 736 are present. Although not shown explicitly in the interest of clarity, coverage areas may overlap and a UE may be able to connect to BS 712 using a coverage area that is selected from among two or more available coverage areas.

[0079] FIG. 8 is a simplified protocol diagram illustrating BS and UE operations making use of a physical random access channel (PRACH) for initial UE boot-up. At 802, as a default operation, BS 712 periodically broadcasts a synchronization signal block, which contains information on where (in terms of time and frequency) a system information broadcast may be found. When a UE, such as UE 730, 732, 734, or 736 first boots up, it detects a synchronization signal block broadcast by the BS, such as BS 712, and uses the information that it provides to listen for the system information broadcast. The system

information broadcast supplies various configuration parameters, including the preamble format using a PRACH configuration index indicator, along with random access (RA) channel location in the frequency spectrum and timeslot. Upon receiving the system information, at 804 the UE sends a RA preamble using the PRACH according to the formatting, subchannel, and subframe parameters received from the system information broadcast. In response to receipt of the RA preamble, at 804 the BS sends a random access response (RAR) that includes, among other items, an uplink (UL) grant, timing advance (TA) command information, which the UE uses to correct for propagation delays, and a temporary cell radio network temporary identifier (C-RNTI) for the UE.

[0080] In response to the RAR, at 808 the UE sends a connection request, which may include a global unique identification (GUID) of the UE, and other pertinent information. In response to the connection request, at 810 the BS sends a connection response, which is based on contention resolution performed at the BS, and assigns a cell RNTI (C-RNTI) to the UE.

[0081] Following the connection response message, additional messages may be transmitted, such as network operator controls for example, before radio link control (RLC) is established for UE-BS connectivity.

[0082] The PRACH may have other uses. For example, the PRACH may be further used in contention-free based handover for cell switching. In these situations, the UE uses a RA procedure to transmit information to a new cell's BS. In this context, everything is known about the UE, so the BS may inform neighbor cell BS about UE as well as the RA parameters such as the preamble. Another use for the PRACH is for recovery of lost connections.

[0083] In cells having TRPs utilizing beamforming techniques according to some aspects, the initial access procedure may involve synchronization signals transmitted using different beams. Each beam may be associated with corresponding PRACH resources. Based on synchronization signal detection, the UE may chose the preferred beam and accordingly, the appropriate PRACH resource, for RA preamble transmission.

[0084] According to some embodiments, a BS, such as BS 712, may allocate different amounts of PRACH resources to the various coverage areas that the BS facilitates. FIGs. 9A-9C are diagrams illustrating various examples of PRACH resource allocations that may be performed by a base station. Each of these diagrams shows spectral-temporal resources as a grid, the horizontal rows of which represent time-duration units, such as subframes, for example, and the vertical columns of which represent PRACH bandwidth units of spectrum, such as groups of resource blocks (RBs). Thus, for example, each cell of the grid can represent a group of 72 frequency-domain subcarriers (e.g., 6 resource blocks) over a duration of a subframe.

[0085] In the embodiments of FIGs. 9A-9C, different amounts of PRACH resources are allocated to different coverage areas. In the examples depicted, PRACH resources 912, 932, and 952 are allocated to a first coverage area, PRACH resources 914, 934, and 954 are allocated to a second coverage area, and PRACH resources 916, 936, and 956 are allocated to a third coverage area. As discussed above, the coverage areas may be defined based on beam direction, TRP, or the like.

[0086] In the example of FIG. 9 A, each PRACH resource has the same bandwidth and duration (i.e., preamble length). The bandwidth of each PRACH resource is indicated at 904, and the duration is indicated at 906. In this example, three distinct PRACH resources 912 are allocated to the first coverage area, two PRACH resources 914 are allocated to the second coverage area, and one PRACH resource 916 is allocated to the third coverage area. Each PRACH resource 912-916 may be identified by the BS in terms of its subframe number and frequency offset index 902.

[0087] In the example of FIG. 9B, the PRACH resources have the same duration (i.e., preamble length) 926, but they may have varying bandwidths.

Here, each coverage area is associated with one PRACH resource; however, the PRACH resources have varying bandwidth 924. PRACH resource 932 occupies three PRACH BW units, whereas PRACH resource 934 occupies two PRACH BW units, and PRACH resource 936 occupies one PRACH unit, as depicted. Each PRACH resource 932-936 may be identified by its subframe number, frequency offset index 922, and bandwidth 924.

[0088] In the example of FIG. 9C, the PRACH resources have the same bandwidth 944, but they each have varying durations (i.e., preamble lengths) 946. As depicted, PRACH resource 952 has a duration 946 corresponding to three subframes, whereas PRACH resource 954 has a duration 946 of two subframes, and PRACH resource 956 has a duration 946 of one subframe. Each PRACH resource 952-956 may be identified by its subframe number, frequency offset index 942, and duration 946 (which may be represented as preamble type index).

[0089] In related embodiments (not shown) PRACH resources may be allocated that are defined as combinations of quantity-variable, bandwidth- variable, and duration-variable PRACH resources. In addition, PRACH resources may be allocated to different coverage areas with varying transmit power indicia particularized to the PRACH resource parameter information- containing broadcast signaling. Regardless of how the size, quantity, or transmit power of PRACH resources may be varied as among the coverage areas within a cell serviced by a base station, in the present context, the variation of PRACH resource quantity, bandwidth, duration, or transmit power level, or variation of some combination of these parameters, is referred to as a variable amount of PRACH resources.

[0090] FIG. 10 is a flow diagram illustrating operations that may be performed by a base station to facilitate multiple coverage areas within the cell, in accordance with some embodiments. As depicted, process 1000 may be performed by application processor 305 and associated circuitry of base station radio head 300 (FIG. 3), or by a system having a different architecture. Notably, process 1000 is a machine-implemented process that operates autonomously (e.g., without user interaction). In addition, it is important to note that process 1000 is a richly-featured embodiment that may be realized as described; in addition, portions of the process may be implemented while others are excluded in various embodiments. The following Additional Notes and Examples section details various combinations, without limitation, that are contemplated. It should also be noted that in various embodiments, certain process operations may be performed in a different ordering than depicted in FIG. 10.

[0091] At 1002, the BS stores a listing of multiple coverage areas that it facilitates as part of a database or other suitable data structure. As discussed above, the multiple coverage areas may be implemented with different beam directions, different TRPs, or some combination of these. At 1004, the BS generates or receives allocations of PRACH resources for each of the coverage areas. In some examples, the BS may autonomously determine the quantity, bandwidth, spectral location, duration, and transmit power for PRACH resources to be allocated to each coverage area, based on a suitable PRACH resource allocation algorithm, rule set, heuristics, or other computational decision process. In other examples, the BS may receive the allocations from an external source, such as a eNB controller, gNB controller, or the like.

[0092] At 1006, the BS stores the allocated PRACH resources in association with the corresponding coverage areas. The PRACH resource allocations may be stored in the data structure in which the listing of coverage areas is maintained, for example. Notably, different amounts of PRACH resources may be allocated to, and stored in association with, the various coverage areas.

[0093] At 1008, the BS associates each coverage area with a transmit power level, which may be represented as a power offset value in some embodiments. The power level information may be stored in association with the corresponding list of coverage areas. Notably, different power levels may be associated with the different coverage areas.

[0094] At 1010, the BS broadcasts coverage area-specific PRACH

configuration parameters and power offset information to each coverage area as part of the system broadcast information. In some embodiments, the system broadcast information includes the PRACH parameters and power offset information for every coverage area of the cell that is facilitated by the BS, such that the system broadcast information contains the same set of information for each coverage area. In another type of embodiment, the system broadcast information may be different for individual ones of the coverage areas. The

PRACH configuration parameters may be specified in terms of frequency offset, bandwidth, subframe or slot identifiers, duration, or in another suitable an unambiguous fashion (e.g., using indices that the UE may use to look up

PRACH resource parameters). The broadcast may be established using higher- layer messaging using a higher abstraction layer than the physical layer. For example, a transport channel at the medium access control (MAC) layer may be used to specify the PRACH resource parameters and transmit power information. The broadcast may be issued periodically for each coverage area, and may be associated with the synchronization signaling broadcast that UEs listen for on power-up. Notably, each coverage area may have differing PRACH resource parameters and transmit power level information broadcast into it. Among the differing PRACH resource parameters, each coverage area may specify the use of one or more preambles that differ from the preambles of other nearby coverage areas, or that differ from all other coverage areas of the cell facilitated by the BS.

[0095] At 1012, the BS monitors the allocated PRACH resources for the presence of RA preambles that may be transmitted by UEs. Notably, because the PRACH resources are non-uniformly allocated to the various coverage areas, the coverage areas are monitored to varying extent relative to one another. [0096] At 1014, in response to each RA preamble received, the BS executes a RA protocol with the corresponding UEs. An example of a RA protocol is described above with reference to FIG. 8.

[0097] In a related example, at 1016, the BS collects usage trends of the various coverage areas. For instance, as depicted, the BS may log UE

populations per coverage area. This information may be statistically aggregated and analyzed as a function of time of day to ascertain prevailing usage patterns for the individual coverage areas.

[0098] At 1018, the BS may re-allocate the PRACH resources to the various coverage areas. The re-allocation may be based on per-coverage-area UE population trends determined at 1016. At 1020, the BS may adjust the transmit power indicia for individual ones of the coverage areas. The re-allocation of PRACH resources, and the adjustment of the transmit power indicia may be performed on a periodic basis by the BS, or in response to some detected event or occurrence, such as in response to a detected change in UE population that exceeds a change threshold in some defined number of the coverage areas, for instance.

[0099] FIG. 11 is a flow diagram illustrating operations that may be performed by a user device operating in a cell having multiple coverage areas to facilitate selection of a coverage area through which to connect to the base station serving the cell, according to some embodiments. As depicted, process 1100 may be performed by application processor 205 and associated circuitry of UE 200 (FIG. 2), or by a system having a different architecture. Process 1100 is a machine- implemented process that operates autonomously (e.g., without user interaction), though it may be initiated by a user. In addition, process 1100 is a richly- featured embodiment that may be realized as described; in addition, portions of the process may be implemented while others are excluded in various

embodiments. The following Additional Notes and Examples section details various combinations, without limitation, that are contemplated. It should also be noted that in various embodiments, certain process operations may be performed in a different ordering than depicted in FIG. 11.

[0100] At 1102, the UE is powered on, and begins listening for

synchronization signaling, from which the UE determines where to listen for the system broadcast information, which includes RACH configuration information. The RACH configuration information may include coverage-area-specific time/frequency resource identifiers and transmit power information (e.g., power offset value) of the PRACH resources corresponding to the associated coverage area. The BS can provide multiple RACH configurations for multiple coverage areas in a single system information broadcast.

[0101] At 1104, upon receiving the RACH configuration information, the UE computes the transmit power of the PRACH transmission for a coverage area. As an example, the transmit power of the PRACH transmission is computed by first computing the path loss, PL, which is measured by subtracting the received signal power from the transmit power of the reference signal associated with the PRACH coverage area, and adding the power offset associated with the PRACH coverage area (communicated to the UE as part of the RACH configuration information) to the computed path loss to obtain the final transmit power:

PL k = Ptx,k - Prx,k,

PRACH Tx Power = Power offset + PL k,

Where Ptx,k is the transmit power of the reference signal associated with a coverage area k, Prx,k is the measured received power of the reference signal associated with coverage area k, with values being expressed in decibels (dB).

[0102] At 1106, the UE may compute additional transmit power values for PRACH transmissions for one or more other coverage areas that the UE may have discovered based on the received RACH configuration information pertaining to those coverage areas. The UE further discovers which of the coverage areas are available to it based on which synchronization signal blocks it may have heard.

[0103] At 1108 the UE selects a coverage area in which to transmit a RA preamble via a PRACH based on the transmit power of the PRACH

corresponding to the one or more coverage areas and the received power of the reference signaling associated with the same coverage areas. For example, if the received signal power of different reference signals associated with different coverages area is similar, the UE can choose a PRACH resource for which a smaller transmit power may be used to preserve UE battery life.

[0104] At 1110 the UE transmits PRACH in the PRACH resource

corresponding to the selected coverage area using the computed transmit power associated with the selected PRACH resource. [0105] At 1112 the UE carries out the RA protocol with the BS, including receiving a random access response (RAR) transmitted by the BS in response to the PRACH preamble, and other operations discussed above in connection with FIG. 8.

[0106] Additional notes and examples:

[0107] Example 1 is apparatus of a base station (BS) configurable for facilitating multiple coverage areas in a cell, the apparatus comprising: memory; and processing circuitry to: store, in the memory, allocations of different amounts of physical random access channel (PRACH) resources in association with different ones of the multiple coverage areas; initiate informational broadcasting that includes coverage area-specific PRACH resource configuration parameters; initiate monitoring of the different amounts of PRACH resources in the different ones of the multiple coverage areas; and in response to receipt of a random-access preamble from a user equipment (UE) device on any PRACH resource, initiate a random-access connection protocol with that UE device.

[0108] In Example 2, the subject matter of Example 1 optionally includes wherein the informational broadcasting is directed to the multiple coverage areas and includes coverage area-specific PRACH resource configuration parameters for every one of the multiple coverage areas.

[0109] In Example 3, the subject matter of any one or more of Examples 1-2 optionally include wherein the processing circuitry is to further determine the allocations of the different amounts of the PRACH resources for the different ones of the multiple coverage areas.

[0110] In Example 4, the subject matter of any one or more of Examples 1-3 optionally include wherein the allocations of the different amounts of the

PRACH resources for the different ones of the multiple coverage areas are based on measurement of UE usage trends among the multiple coverage areas.

[0111] In Example 5, the subject matter of any one or more of Examples 1-4 optionally include wherein the processing circuitry is to further store, in the memory, different transmit power levels in association with the different PRACH resources of the different ones of the multiple coverage areas.

[0112] In Example 6, the subject matter of Example 5 optionally includes wherein the RACH resource configuration parameters include a coverage area- specific transmit power level representation. [0113] In Example 7, the subject matter of any one or more of Examples 5-6 optionally include wherein the processing circuitry is to further adjust at least one of the different transmit power levels corresponding to at least one of the multiple coverage areas.

[0114] In Example 8, the subject matter of any one or more of Examples 1-7 optionally include wherein at least some of the multiple coverage areas are established in accordance with distinct beam directions transmitted by the BS.

[0115] In Example 9, the subject matter of any one or more of Examples 1-8 optionally include wherein at least some of the multiple coverage areas are established in accordance with distinct transmission/reception points (TRPs) situated in distinct locations, that are part of the BS.

[0116] In Example 10, the subject matter of any one or more of Examples 1-9 optionally include wherein at least some of the multiple coverage areas vary in size.

[0117] In Example 11, the subject matter of any one or more of Examples 1-10 optionally include wherein the allocations of different amounts of the PRACH resources include variations in quantity of the PRACH resources allocated to different ones of the multiple coverage areas.

[0118] In Example 12, the subject matter of any one or more of Examples 1-11 optionally include wherein the allocations of different amounts of the PRACH resources include variations in bandwidth of the PRACH resources allocated to different ones of the multiple coverage areas.

[0119] In Example 13, the subject matter of any one or more of Examples 1-12 optionally include wherein the allocations of different amounts of the PRACH resources include variations in duration of the PRACH resources allocated to different ones of the multiple coverage areas.

[0120] In Example 14, the subject matter of any one or more of Examples 1-13 optionally include wherein the allocations of different amounts of the PRACH resources include variations in transmit power level indication associated with the PRACH resources allocated to different ones of the multiple coverage areas.

[0121] In Example 15, the subject matter of any one or more of Examples 1-14 optionally include wherein the allocations of different amounts of the PRACH resources are non-uniformly distributed across the multiple coverage areas. [0122] In Example 16, the subject matter of any one or more of Examples 1-15 optionally include wherein the allocations of different amounts of the PRACH resources are distributed across the multiple coverage areas based on variations in size among different ones of the multiple coverage areas.

[0123] In Example 17, the subject matter of any one or more of Examples 1-16 optionally include wherein the allocations of different amounts of the PRACH resources are distributed across the multiple coverage areas based on variations UE loading within different ones of the multiple coverage areas.

[0124] In Example 18, the subject matter of any one or more of Examples 1-17 optionally include wherein the allocations of different amounts of the PRACH resources are distributed across the multiple coverage areas based on variations in transmit power level associated with different ones of the multiple coverage areas.

[0125] In Example 19, the subject matter of any one or more of Examples 1-18 optionally include at least one antenna, and radio transceiver circuitry operatively coupled with the antenna and configured to facilitate the multiple coverage areas.

[0126] Example 20 is apparatus of user equipment (UE) configured to communicate with a base station (BS) that facilitates a cell of a radio access network, the apparatus comprising: memory; and processing circuitry to: decode received informational broadcast data that includes coverage area-specific physical random access channel PRACH resource configuration parameters for a plurality of coverage areas facilitated by the BS within the cell, the PRACH resource configuration parameters including coverage area-specific transmit power indicia; compute first transmit power to be used for communicating via a first set of PRACH resources corresponding to a first coverage area of the plurality of coverage areas; compute second transmit power to be used for communicating via a second set of PRACH resources corresponding to a second coverage area of the plurality of coverage areas; determine a selected set of PRACH resources corresponding to a selected coverage area to be used for initiating communications with the BS via a random-access protocol, wherein the determination is based on a comparison of the first transmit power and the second transmit power; and initiate transmission of a PRACH signal preamble via the selected set of PRACH resources in accordance with the random-access protocol.

[0127] In Example 21, the subject matter of Example 20 optionally includes wherein information broadcast data includes coverage area-specific PRACH resource configuration parameters for every one of the multiple coverage areas.

[0128] In Example 22, the subject matter of any one or more of Examples 20-

21 optionally include wherein the PRACH resource configuration parameters include indicia of different amounts of PRACH resources corresponding to the different coverage areas.

[0129] In Example 23, the subject matter of any one or more of Examples 20-

22 optionally include wherein the processing circuitry is to further discover a set of coverage areas that are available to the UE based on the received

informational broadcast data specific to individual ones of the coverage areas.

[0130] In Example 24, the subject matter of any one or more of Examples 20- 23 optionally include wherein computation of the first transmit power and the second transmit power is each based on a transmit power of a reference signal associated with a corresponding coverage area received as part of the coverage area-specific transmit power indicia, a measured received power of the reference signal , and a power offset value received as part of the coverage area-specific transmit power indicia.

[0131] In Example 25, the subject matter of any one or more of Examples 20-

24 optionally include wherein determination of the selected set of PRACH resources corresponding to a selected coverage area is based on a lowest computed transmit power from among the first transmit power and the second transmit power.

[0132] In Example 26, the subject matter of any one or more of Examples 20-

25 optionally include at least one antenna, and radio transceiver circuitry operatively coupled with the antenna.

[0133] Example 27 is at least one machine-readable medium containing instructions that, when executed by a processor of a base station (BS) configurable for facilitating multiple coverage areas in a cell, cause the BS to: store allocations of different amounts of physical random access channel (PRACH) resources in association with different ones of the multiple coverage areas; initiate informational broadcasting that includes coverage area-specific PRACH resource configuration parameters; initiate monitoring of the different amounts of PRACH resources in the different ones of the multiple coverage areas; and in response to receipt of a random-access preamble from a user equipment (UE) device on any PRACH resource, initiate a random-access connection protocol with that UE device.

[0134] In Example 28, the subject matter of Example 27 optionally includes wherein the informational broadcasting is directed to the multiple coverage areas and includes coverage area-specific PRACH resource configuration parameters for every one of the multiple coverage areas.

[0135] In Example 29, the subject matter of any one or more of Examples 27- 28 optionally include wherein the instructions are to further cause the BS to determine the allocations of the different amounts of the PRACH resources for the different ones of the multiple coverage areas.

[0136] In Example 30, the subject matter of any one or more of Examples 27- 29 optionally include wherein the allocations of the different amounts of the

[0137] In Example 31, the subject matter of any one or more of Examples 27- 30 optionally include wherein the instructions are to further cause the BS to store different transmit power levels in association with the different PRACH resources of the different ones of the multiple coverage areas.

[0138] In Example 32, the subject matter of Example 31 optionally includes wherein the RACH resource configuration parameters include a coverage area- specific transmit power level representation.

[0139] In Example 33, the subject matter of any one or more of Examples 31- 32 optionally include wherein the instructions are to further cause the BS to adjust at least one of the different transmit power levels corresponding to at least one of the multiple coverage areas.

[0140] In Example 34, the subject matter of any one or more of Examples 27- 33 optionally include wherein at least some of the multiple coverage areas are established in accordance with distinct beam directions transmitted by the BS.

[0141] In Example 35, the subject matter of any one or more of Examples 27- 34 optionally include wherein at least some of the multiple coverage areas are established in accordance with distinct transmission/reception points (TRPs) situated in distinct locations, that are part of the BS.

[0142] In Example 36, the subject matter of any one or more of Examples 27-

35 optionally include wherein at least some of the multiple coverage areas vary in size.

[0143] In Example 37, the subject matter of any one or more of Examples 27-

36 optionally include wherein the allocations of different amounts of the PRACH resources include variations in quantity of the PRACH resources allocated to different ones of the multiple coverage areas.

[0144] In Example 38, the subject matter of any one or more of Examples 27-

37 optionally include wherein the allocations of different amounts of the PRACH resources include variations in bandwidth of the PRACH resources allocated to different ones of the multiple coverage areas.

[0145] In Example 39, the subject matter of any one or more of Examples 27- 38 optionally include wherein the allocations of different amounts of the PRACH resources include variations in duration of the PRACH resources allocated to different ones of the multiple coverage areas.

[0146] In Example 40, the subject matter of any one or more of Examples 27-

39 optionally include wherein the allocations of different amounts of the PRACH resources include variations in transmit power level indication associated with the PRACH resources allocated to different ones of the multiple coverage areas.

[0147] In Example 41, the subject matter of any one or more of Examples 27-

40 optionally include wherein the allocations of different amounts of the PRACH resources are non-uniformly distributed across the multiple coverage areas.

[0148] In Example 42, the subject matter of any one or more of Examples 27-

41 optionally include wherein the allocations of different amounts of the PRACH resources are distributed across the multiple coverage areas based on variations in size among different ones of the multiple coverage areas.

[0149] In Example 43, the subject matter of any one or more of Examples 27-

42 optionally include wherein the allocations of different amounts of the PRACH resources are distributed across the multiple coverage areas based on variations UE loading within different ones of the multiple coverage areas. [0150] In Example 44, the subject matter of any one or more of Examples 27- 43 optionally include wherein the allocations of different amounts of the PRACH resources are distributed across the multiple coverage areas based on variations in transmit power level associated with different ones of the multiple coverage areas.

[0151] Example 45 is at least one machine-readable medium containing instructions that, when executed by a processor of user equipment (UE) configured to communicate with a base station (BS) that facilitates a cell of a radio access network, cause the UE to: decode received informational broadcast data that includes coverage area-specific physical random access channel PRACH resource configuration parameters for a plurality of coverage areas facilitated by the BS within the cell, the PRACH resource configuration parameters including coverage area-specific transmit power indicia; compute first transmit power to be used for communicating via a first set of PRACH resources corresponding to a first coverage area of the plurality of coverage areas; compute second transmit power to be used for communicating via a second set of PRACH resources corresponding to a second coverage area of the plurality of coverage areas; determine a selected set of PRACH resources corresponding to a selected coverage area to be used for initiating

communications with the BS via a random-access protocol, wherein the determination is based on a comparison of the first transmit power and the second transmit power; and initiate transmission of a PRACH signal preamble via the selected set of PRACH resources in accordance with the random-access protocol.

[0152] In Example 46, the subject matter of Example 45 optionally includes wherein information broadcast data includes coverage area-specific PRACH resource configuration parameters for every one of the multiple coverage areas.

[0153] In Example 47, the subject matter of any one or more of Examples 45-

46 optionally include wherein the PRACH resource configuration parameters include indicia of different amounts of PRACH resources corresponding to the different coverage areas.

[0154] In Example 48, the subject matter of any one or more of Examples 45-

47 optionally include wherein the instructions are to further cause the BS to discover a set of coverage areas that are available to the UE based on the received informational broadcast data specific to individual ones of the coverage areas.

[0155] In Example 49, the subject matter of any one or more of Examples 45-

48 optionally include wherein computation of the first transmit power and the second transmit power is each based on a transmit power of a reference signal associated with a corresponding coverage area received as part of the coverage area-specific transmit power indicia, a measured received power of the reference signal , and a power offset value received as part of the coverage area-specific transmit power indicia.

[0156] In Example 50, the subject matter of any one or more of Examples 45-

49 optionally include wherein determination of the selected set of PRACH resources corresponding to a selected coverage area is based on a lowest computed transmit power from among the first transmit power and the second transmit power.

[0157] Example 51 is a base station (BS) configurable for facilitating multiple coverage areas in a cell, the BS comprising: means for storing allocations of different amounts of physical random access channel (PRACH) resources in association with different ones of the multiple coverage areas; means for initiating informational broadcasting that includes coverage area-specific PRACH resource configuration parameters; means for initiating monitoring of the different amounts of PRACH resources in the different ones of the multiple coverage areas; and means for initiating a random-access connection protocol with that UE device in response to receipt of a random-access preamble from a user equipment (UE) device on any PRACH resource.

[0158] In Example 52, the subject matter of Example 51 optionally includes wherein the informational broadcasting is directed to the multiple coverage areas and includes coverage area-specific PRACH resource configuration parameters for every one of the multiple coverage areas.

[0159] In Example 53, the subject matter of any one or more of Examples 51- 52 optionally include means for determining the allocations of the different amounts of the PRACH resources for the different ones of the multiple coverage areas.

[0160] In Example 54, the subject matter of any one or more of Examples 51- 53 optionally include wherein the allocations of the different amounts of the PRACH resources for the different ones of the multiple coverage areas are based on measurement of UE usage trends among the multiple coverage areas.

[0161] In Example 55, the subject matter of any one or more of Examples 51- 54 optionally include means for storing different transmit power levels in association with the different PRACH resources of the different ones of the multiple coverage areas.

[0162] In Example 56, the subject matter of Example 55 optionally includes wherein the RACH resource configuration parameters include a coverage area- specific transmit power level representation.

[0163] In Example 57, the subject matter of any one or more of Examples 55-

56 optionally include means for adjusting at least one of the different transmit power levels corresponding to at least one of the multiple coverage areas.

[0164] In Example 58, the subject matter of any one or more of Examples 51-

57 optionally include wherein at least some of the multiple coverage areas are established in accordance with distinct beam directions transmitted by the BS.

[0165] In Example 59, the subject matter of any one or more of Examples 51-

58 optionally include wherein at least some of the multiple coverage areas are established in accordance with distinct transmission/reception points (TRPs) situated in distinct locations, that are part of the BS.

[0166] In Example 60, the subject matter of any one or more of Examples 51-

59 optionally include wherein at least some of the multiple coverage areas vary in size.

[0167] In Example 61, the subject matter of any one or more of Examples 51-

60 optionally include wherein the allocations of different amounts of the PRACH resources include variations in quantity of the PRACH resources allocated to different ones of the multiple coverage areas.

[0168] In Example 62, the subject matter of any one or more of Examples 51-

61 optionally include wherein the allocations of different amounts of the PRACH resources include variations in bandwidth of the PRACH resources allocated to different ones of the multiple coverage areas.

[0169] In Example 63, the subject matter of any one or more of Examples 51-

62 optionally include wherein the allocations of different amounts of the PRACH resources include variations in duration of the PRACH resources allocated to different ones of the multiple coverage areas. [0170] In Example 64, the subject matter of any one or more of Examples 51-

63 optionally include wherein the allocations of different amounts of the PRACH resources include variations in transmit power level indication associated with the PRACH resources allocated to different ones of the multiple coverage areas.

[0171] In Example 65, the subject matter of any one or more of Examples 51-

64 optionally include wherein the allocations of different amounts of the PRACH resources are non-uniformly distributed across the multiple coverage areas.

[0172] In Example 66, the subject matter of any one or more of Examples 51-

65 optionally include wherein the allocations of different amounts of the PRACH resources are distributed across the multiple coverage areas based on variations in size among different ones of the multiple coverage areas.

[0173] In Example 67, the subject matter of any one or more of Examples 51- 66 optionally include wherein the allocations of different amounts of the

PRACH resources are distributed across the multiple coverage areas based on variations UE loading within different ones of the multiple coverage areas.

[0174] In Example 68, the subject matter of any one or more of Examples 51-

67 optionally include wherein the allocations of different amounts of the PRACH resources are distributed across the multiple coverage areas based on variations in transmit power level associated with different ones of the multiple coverage areas.

[0175] Example 69 is a user equipment (UE) device configured to

communicate with a base station (BS) that facilitates a cell of a radio access network, the UE device comprising: means for decoding received informational broadcast data that includes coverage area-specific physical random access channel PRACH resource configuration parameters for a plurality of coverage areas facilitated by the BS within the cell, the PRACH resource configuration parameters including coverage area-specific transmit power indicia; means for computing first transmit power to be used for communicating via a first set of PRACH resources corresponding to a first coverage area of the plurality of coverage areas; means for computing second transmit power to be used for communicating via a second set of PRACH resources corresponding to a second coverage area of the plurality of coverage areas; means for determining a selected set of PRACH resources corresponding to a selected coverage area to be used for initiating communications with the BS via a random-access protocol, wherein the determination is based on a comparison of the first transmit power and the second transmit power; and means for initiating transmission of a PRACH signal preamble via the selected set of PRACH resources in accordance with the random-access protocol.

[0176] In Example 70, the subject matter of Example 69 optionally includes wherein information broadcast data includes coverage area-specific PRACH resource configuration parameters for every one of the multiple coverage areas.

[0177] In Example 71, the subject matter of any one or more of Examples 69- 70 optionally include wherein the PRACH resource configuration parameters include indicia of different amounts of PRACH resources corresponding to the different coverage areas.

[0178] In Example 72, the subject matter of any one or more of Examples 69- 71 optionally include means for causing the BS to discover a set of coverage areas that are available to the UE based on the received informational broadcast data specific to individual ones of the coverage areas.

[0179] In Example 73, the subject matter of any one or more of Examples 69-

72 optionally include wherein computation of the first transmit power and the second transmit power is each based on a transmit power of a reference signal associated with a corresponding coverage area received as part of the coverage area-specific transmit power indicia, a measured received power of the reference signal , and a power offset value received as part of the coverage area-specific transmit power indicia.

[0180] In Example 74, the subject matter of any one or more of Examples 69-

73 optionally include wherein determination of the selected set of PRACH resources corresponding to a selected coverage area is based on a lowest computed transmit power from among the first transmit power and the second transmit power.

[0181] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments that may be practiced. These embodiments are also referred to herein as "examples." Such examples may include elements in addition to those shown or described. However, also contemplated are examples that include the elements shown or described.

Moreover, also contemplated are examples using any combination or

permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.

[0182] Publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference(s) are supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document controls.

[0183] In this document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of "at least one" or "one or more." In this document, the term "or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, that is, a system, device, article, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to suggest a numerical order for their objects.

[0184] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with others. Other embodiments may be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. However, the claims may not set forth every feature disclosed herein as embodiments may feature a subset of said features. Further, embodiments may include fewer features than those disclosed in a particular example. Thus, the following claims are hereby incorporated into the Detailed Description, with a claim standing on its own as a separate embodiment. The scope of the embodiments disclosed herein is to be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

CLAIMS What is claimed is:

1. Apparatus of a base station (BS) configurable for facilitating multiple coverage areas in a cell, the apparatus comprising:

memory; and

processing circuitry to:

store, in the memory, allocations of different amounts of physical random access channel (PRACH) resources in association with different ones of the multiple coverage areas;

initiate informational broadcasting that includes coverage area- specific PRACH resource configuration parameters;

initiate monitoring of the different amounts of PRACH resources in the different ones of the multiple coverage areas; and

in response to receipt of a random-access preamble from a user equipment (UE) device on any PRACH resource, initiate a random- access connection protocol with that UE device.

2. The apparatus of claim 1, wherein the processing circuitry is to further determine the allocations of the different amounts of the PRACH resources for the different ones of the multiple coverage areas.

3. The apparatus of claim 1, wherein the processing circuitry is to further store, in the memory, different transmit power levels in association with the different PRACH resources of the different ones of the multiple coverage areas.

4. The apparatus of claim 3, wherein the RACH resource configuration parameters include a coverage area-specific transmit power level representation.

5. The apparatus of claim 3, wherein the processing circuitry is to further adjust at least one of the different transmit power levels corresponding to at least one of the multiple coverage areas.

6. The apparatus of claim 1, wherein at least some of the multiple coverage areas are established in accordance with distinct beam directions transmitted by the BS.

7. The apparatus of claim 1, wherein at least some of the multiple coverage areas are established in accordance with distinct transmission/reception points (TRPs) situated in distinct locations, that are part of the BS.

8. The apparatus of claim 1, wherein the allocations of different amounts of the PRACH resources include variations in quantity of the PRACH resources allocated to different ones of the multiple coverage areas.

9. The apparatus of claim 1, wherein the allocations of different amounts of the PRACH resources include variations in bandwidth of the PRACH resources allocated to different ones of the multiple coverage areas.

10. The apparatus of claim 1, wherein the allocations of different amounts of the PRACH resources include variations in duration of the PRACH resources allocated to different ones of the multiple coverage areas.

11. The apparatus of claim 1, wherein the allocations of different amounts of the PRACH resources include variations in transmit power level indication associated with the PRACH resources allocated to different ones of the multiple coverage areas.

12. The apparatus of claim 1, wherein the allocations of different amounts of the PRACH resources are non-uniformly distributed across the multiple coverage areas.

13. The apparatus according to any one of claims 1-12, further comprising: at least one antenna, and radio transceiver circuitry operatively coupled with the antenna and configured to facilitate the multiple coverage areas.

14. Apparatus of user equipment (UE) configured to communicate with a base station (BS) that facilitates a cell of a radio access network, the apparatus comprising:

memory; and

processing circuitry to:

decode received informational broadcast data that includes coverage area-specific physical random access channel PRACH resource configuration parameters for a plurality of coverage areas facilitated by the BS within the cell, the PRACH resource configuration parameters including coverage area-specific transmit power indicia;

compute first transmit power to be used for communicating via a first set of PRACH resources corresponding to a first coverage area of the plurality of coverage areas;

compute second transmit power to be used for communicating via a second set of PRACH resources corresponding to a second coverage area of the plurality of coverage areas;

determine a selected set of PRACH resources corresponding to a selected coverage area to be used for initiating communications with the BS via a random-access protocol, wherein the determination is based on a comparison of the first transmit power and the second transmit power; and

initiate transmission of a PRACH signal preamble via the selected set of PRACH resources in accordance with the random-access protocol.

15. The apparatus of claim 14, wherein information broadcast data includes coverage area-specific PRACH resource configuration parameters for every one of the multiple coverage areas.

16. The apparatus of claim 14, wherein the PRACH resource configuration parameters include indicia of different amounts of PRACH resources corresponding to the different coverage areas.

17. The apparatus of claim 14, wherein the processing circuitry is to further discover a set of coverage areas that are available to the UE based on the received informational broadcast data specific to individual ones of the coverage areas.

18. The apparatus according to any one of claims 14-17, wherein

computation of the first transmit power and the second transmit power is each based on a transmit power of a reference signal associated with a corresponding coverage area received as part of the coverage area-specific transmit power indicia, a measured received power of the reference signal , and a power offset value received as part of the coverage area-specific transmit power indicia.

19. The apparatus according to any one of claims 14-17, wherein

determination of the selected set of PRACH resources corresponding to a selected coverage area is based on a lowest computed transmit power from among the first transmit power and the second transmit power.

20. The apparatus according to any one of claims 14-17, further comprising: at least one antenna, and radio transceiver circuitry operatively coupled with the antenna.

21. At least one machine-readable medium containing instructions that, when executed by a processor of a base station (BS) configurable for facilitating multiple coverage areas in a cell, cause the BS to:

store allocations of different amounts of physical random access channel

(PRACH) resources in association with different ones of the multiple coverage areas;

initiate informational broadcasting that includes coverage area-specific PRACH resource configuration parameters;

in response to receipt of a random-access preamble from a user equipment (UE) device on any PRACH resource, initiate a random-access connection protocol with that UE device.

22. The at least one machine-readable medium of claim 21, wherein the allocations of the different amounts of the PRACH resources for the different ones of the multiple coverage areas are based on measurement of UE usage trends among the multiple coverage areas.

23. The at least one machine-readable medium of claim 21, wherein the allocations of different amounts of the PRACH resources are distributed across the multiple coverage areas based on variations in size among different ones of the multiple coverage areas.

24. The at least one machine-readable medium according to any one of claims 21-23, wherein the allocations of different amounts of the PRACH resources are distributed across the multiple coverage areas based on variations UE loading within different ones of the multiple coverage areas.

25. The at least one machine-readable medium according to any one of claims 21-23, wherein the allocations of different amounts of the PRACH resources are distributed across the multiple coverage areas based on variations in transmit power level associated with different ones of the multiple coverage areas.