WO2020164017A1

WO2020164017A1 - Flexible bandwidth design for physical broadcast channel

Info

Publication number: WO2020164017A1
Application number: PCT/CN2019/074984
Authority: WO
Inventors: Changlong Xu; Chao Wei; Hao Xu
Original assignee: Qualcomm Incorporated
Priority date: 2019-02-13
Filing date: 2019-02-13
Publication date: 2020-08-20

Abstract

Certain aspects of the present disclosure provide techniques for a flexible bandwidth design for a physical broadcast channel. An exemplary method generally includes generating bits of information for transmission on a physical broadcast channel (PBCH) spanning a plurality of subcarriers, encoding the bits of information using a polar code, mapping the encoded bits of information to the plurality of subcarriers and a plurality of symbols, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation, and transmitting the encoded bits of information over the plurality of subcarriers and the plurality of symbols according to the mapping.

Description

FLEXIBLE BANDWIDTH DESIGN FOR PHYSICAL BROADCAST CHANNEL

BACKGROUND

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for a flexible bandwidth design for a physical broadcast channel.

Description of Related Art

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc. ) . Examples of such multiple-access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE Advanced (LTE-A) systems, code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems, to name a few.

In some examples, a wireless multiple-access communication system may include a number of base stations (BSs) , which are each capable of simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs) . In an LTE or LTE-Anetwork, a set of one or more base stations may define an eNodeB (eNB) . In other examples (e.g., in a next generation, a new radio (NR) , or 5G network) , a wireless multiple access communication system may include a number of distributed units (DUs) (e.g., edge units (EUs) , edge nodes (ENs) , radio heads (RHs) , smart radio heads (SRHs) , transmission reception points (TRPs) , etc. ) in communication with a number of central units (CUs) (e.g., central nodes (CNs) , access node controllers (ANCs) , etc. ) , where a set of one or more DUs, in communication with a CU, may define an access node (e.g., which may be referred to as a BS, 5G NB, next generation NodeB (gNB or gNodeB) , transmission reception point (TRP) , etc. ) . A BS or DU may communicate with a set of UEs on downlink channels (e.g., for transmissions from a BS or DU to a UE) and uplink channels (e.g., for transmissions from a UE to BS or DU) .

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. NR (e.g., new radio or 5G) is an example of an emerging telecommunication standard. NR is a set of enhancements to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL) . To these ends, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in NR and LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

The systems, methods, and devices of the disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure as expressed by the claims which follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this disclosure provide advantages that include improved communications between access points and stations in a wireless network.

Certain aspects provide a method for wireless communication. The method generally includes generating bits of information for transmission on a physical broadcast channel (PBCH) spanning a plurality of subcarriers, encoding the bits of information using a polar code, mapping the encoded bits of information to the plurality of subcarriers and a plurality of symbols, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation, and transmitting the encoded bits of information over the plurality of subcarriers and the plurality of symbols according to the mapping.

Certain aspects provide an apparatus for wireless communication. The apparatus generally includes at least one processor configured to generate bits of information for transmission on a physical broadcast channel (PBCH) spanning a plurality of subcarriers, encode the bits of information using a polar code, map the encoded bits of information to the plurality of subcarriers and a plurality of symbols, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation, and transmit the encoded bits of information over the plurality of subcarriers and the plurality of symbols according to the mapping. The apparatus also generally includes a memory coupled with the at least one processor.

Certain aspects provide an apparatus for wireless communication. The apparatus generally includes means for generating bits of information for transmission on a physical broadcast channel (PBCH) spanning a plurality of subcarriers, means for encoding the bits of information using a polar code, means for mapping the encoded bits of information to the plurality of subcarriers and a plurality of symbols, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation, and means for transmitting the encoded bits of information over the plurality of subcarriers and the plurality of symbols according to the mapping.

Certain aspects provide a non-transitory computer readable medium for wireless communication. The non-transitory computer readable medium generally includes instructions that, when executed by at least one processor, cause the at least one processor to generate bits of information for transmission on a physical broadcast channel (PBCH) spanning a plurality of subcarriers, encode the bits of information using a polar code, map the encoded bits of information to the plurality of subcarriers and a plurality of symbols, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation, and transmit the encoded bits of information over the plurality of subcarriers and the plurality of symbols according to the mapping.

Certain aspects provide a method for wireless communication. The method generally includes receiving encoded bits of information transmitted on a physical broadcast channel according to a mapping, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation, and decoding the encoded bits of information.

Certain aspects provide an apparatus for wireless communication. The apparatus generally includes at least one processor configured to receive encoded bits of information transmitted on a physical broadcast channel according to a mapping, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation, and decode the encoded bits of information. The apparatus also generally includes a memory coupled with the at least one processor.

Certain aspects provide an apparatus for wireless communication. The apparatus generally includes means for receiving encoded bits of information transmitted on a physical broadcast channel according to a mapping, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation, and means for decoding the encoded bits of information.

Certain aspects provide a non-transitory computer readable medium for wireless communication. The non-transitory computer readable medium generally includes instructions that, when executed by at least one processor, cause the at least one processor to receive encoded bits of information transmitted on a physical broadcast channel according to a mapping, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation, and decode the encoded bits of information.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the appended drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

FIG. 1 is a block diagram conceptually illustrating an example telecommunications system, in accordance with certain aspects of the present disclosure.

FIG. 2 is a block diagram illustrating an example architecture of a distributed radio access network (RAN) , in accordance with certain aspects of the present disclosure.

FIG. 3 is a block diagram showing examples for implementing a communication protocol stack in the example RAN architecture, in accordance with certain aspects of the present disclosure.

FIG. 4 is a block diagram conceptually illustrating a design of an example base station (BS) and user equipment (UE) , in accordance with certain aspects of the present disclosure.

FIG. 5 illustrates an example system architecture for interworking between a 5G System (5GS) and an evolved universal mobile telecommunication system network (E-UTRAN) system, in accordance with certain aspects of the present disclosure.

FIG. 6 illustrates an example of a frame format for a telecommunication system, in accordance with certain aspects of the present disclosure.

FIG. 7 illustrates an example encoding process for a physical broadcast channel, in accordance with certain aspects of the present disclosure.

FIG. 8. illustrates a current PBCH design for Release 15, in accordance with certain aspects of the present disclosure.

FIG. 9 is a flow diagram illustrating example operations for wireless communication by a base station, in accordance with certain aspects of the present disclosure.

FIG. 10 is a flow diagram illustrating example operations for wireless communication by a user equipment, in accordance with certain aspects of the present disclosure.

FIGs. 11-13 illustrate various mapping techniques for a physical broadcast channel, in accordance with certain aspects of the present disclosure.

FIG. 14 illustrates a communications device that may include various components configured to perform operations for the techniques disclosed herein in accordance with aspects of the present disclosure.

FIG. 15 illustrates a communications device that may include various components configured to perform operations for the techniques disclosed herein in accordance with aspects of the present disclosure.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for a flexible bandwidth design for a physical broadcast channel (PBCH) . According to aspects, the techniques presented herein may allow different types of UEs operating at different operating bandwidths to receive and decode the PBCH.

The following description provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects.

The techniques described herein may be used for various wireless communication technologies, such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA) , cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM) . An OFDMA network may implement a radio technology such as NR (e.g. 5G RA) , Evolved UTRA (E-UTRA) , Ultra Mobile Broadband (UMB) , IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS) .

New Radio (NR) is an emerging wireless communications technology under development in conjunction with the 5G Technology Forum (5GTF) . 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-Aand GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP) . cdma2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while aspects may be described herein using terminology commonly associated with 3G and/or 4G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as 5G and later, including NR technologies.

New radio (NR) access (e.g., 5G technology) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or beyond) , millimeter wave (mmW) targeting high carrier frequency (e.g., 25 GHz or beyond) , massive machine type communications MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low-latency communications (URLLC) . These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTI) to meet respective quality of service (QoS) requirements. In addition, these services may co-exist in the same subframe.

Example Wireless Communications System

FIG. 1 illustrates an example wireless communication network 100 in which aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be a New Radio (NR) or 5G network. In some cases, the wireless communications network 100 may use a physical broadcast channel (PBCH) with encoded bits of information mapped according to techniques presented herein to allow for different types of UEs (e.g., operating according to different operating bandwidths) to receive and decode the PBCH.

As illustrated in FIG. 1, the wireless communication network 100 may include a number of base stations (BSs) 110 and other network entities. A BS may be a station that communicates with user equipments (UEs) . Each BS 110 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a Node B (NB) and/or a NB subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term “cell” and next generation NodeB (gNB or gNodeB) , NR BS, 5G NB, access point (AP) , or transmission reception point (TRP) may be interchangeable. In some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in wireless communication network 100 through various types of backhaul interfaces, such as a direct physical connection, a wireless connection, a virtual network, or the like using any suitable transport network.

In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, etc. A frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, a subband, etc. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having an association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG) , UEs for users in the home, etc. ) . A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in FIG. 1, the

BSs

110a, 110b and 110c may be macro BSs for the

macro cells

102a, 102b and 102c, respectively. The BS 110x may be a pico BS for a pico cell 102x. The BSs 110y and 110z may be femto BSs for the

femto cells

102y and 102z, respectively. A BS may support one or multiple (e.g., three) cells.

Wireless communication network 100 may also include relay stations. A relay station is a station that receives a transmission of data and/or other information from an upstream station (e.g., a BS or a UE) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE or a BS) . A relay station may also be a UE that relays transmissions for other UEs. In the example shown in FIG. 1, a relay station 110r may communicate with the BS 110a and a UE 120r in order to facilitate communication between the BS 110a and the UE 120r. A relay station may also be referred to as a relay BS, a relay, etc.

Wireless communication network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BS, pico BS, femto BS, relays, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different impact on interference in the wireless communication network 100. For example, macro BS may have a high transmit power level (e.g., 20 Watts) whereas pico BS, femto BS, and relays may have a lower transmit power level (e.g., 1 Watt) .

Wireless communication network 100 may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operation.

A network controller 130 may couple to a set of BSs and provide coordination and control for these BSs. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with one another (e.g., directly or indirectly) via wireless or wireline backhaul.

The UEs 120 (e.g., 120x, 120y, etc. ) may be dispersed throughout the wireless communication network 100, and each UE may be stationary or mobile. A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE) , a cellular phone, a smart phone, a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc. ) , an entertainment device (e.g., a music device, a video device, a satellite radio, etc. ) , a vehicular component or sensor, a smart meter/sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium. Some UEs may be considered machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., that may communicate with a BS, another device (e.g., remote device) , or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

Certain wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz and the minimum resource allocation (called a “resource block” (RB) ) may be 12 subcarriers (or 180 kHz) . Consequently, the nominal Fast Fourier Transfer (FFT) size may be equal to 128, 256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz) , respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (i.e., 6 resource blocks) , and there may be 1, 2, 4, 8, or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.

While aspects of the examples described herein may be associated with LTE technologies, aspects of the present disclosure may be applicable with other wireless communications systems, such as NR. NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. Multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells.

In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity. Base stations are not the only entities that may function as a scheduling entity. In some examples, a UE may function as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs) , and the other UEs may utilize the resources scheduled by the UE for wireless communication. In some examples, a UE may function as a scheduling entity in a peer-to-peer (P2P) network, and/or in a mesh network. In a mesh network example, UEs may communicate directly with one another in addition to communicating with a scheduling entity.

In FIG. 1, a solid line with double arrows indicates desired transmissions between a UE and a serving BS, which is a BS designated to serve the UE on the downlink and/or uplink. A finely dashed line with double arrows indicates interfering transmissions between a UE and a BS.

FIG. 2 illustrates an example architecture of a distributed Radio Access Network (RAN) 200, which may be implemented in the wireless communication network 100 illustrated in FIG. 1. As shown in FIG. 2, the distributed RAN includes Core Network (CN) 202 and Access Node 208.

The CN 202 may host core network functions. CN 202 may be centrally deployed. CN 202 functionality may be offloaded (e.g., to advanced wireless services (AWS) ) , in an effort to handle peak capacity. The CN 202 may include the Access and Mobility Management Function (AMF) 204 and User Plane Function (UPF) 206. The AMF 204 and UPF 206 may perform one or more of the core network functions.

The AN 208 may communicate with the CN 202 (e.g., via a backhaul interface) . The AN 208 may communicate with the AMF 204 via an N2 (e.g., NG-C) interface. The AN 208 may communicate with the UPF 206 via an N3 (e.g., NG-U) interface. The AN 208 may include a central unit-control plane (CU-CP) 210, one or more central unit-user plane (CU-UPs) 212, one or more distributed units (DUs) 214-218, and one or more Antenna/Remote Radio Units (AU/RRUs) 220-224. The CUs and DUs may also be referred to as gNB-CU and gNB-DU, respectively. One or more components of the AN 208 may be implemented in a gNB 226. The AN 208 may communicate with one or more neighboring gNBs.

The CU-CP 210 may be connected to one or more of the DUs 214-218. The CU-CP 210 and DUs 214-218 may be connected via a F1-C interface. As shown in FIG. 2, the CU-CP 210 may be connected to multiple DUs, but the DUs may be connected to only one CU-CP. Although FIG. 2 only illustrates one CU-UP 212, the AN 208 may include multiple CU-UPs. The CU-CP 210 selects the appropriate CU-UP (s) for requested services (e.g., for a UE) .

The CU-UP (s) 212 may be connected to the CU-CP 210. For example, the DU-UP (s) 212 and the CU-CP 210 may be connected via an E1 interface. The CU-CP (s) 212 may connected to one or more of the DUs 214-218. The CU-UP (s) 212 and DUs 214-218 may be connected via a F1-U interface. As shown in FIG. 2, the CU-CP 210 may be connected to multiple CU-UPs, but the CU-UPs may be connected to only one CU-CP.

A DU, such as

DUs

214, 216, and/or 218, may host one or more TRP (s) (transmit/receive points, which may include an Edge Node (EN) , an Edge Unit (EU) , a Radio Head (RH) , a Smart Radio Head (SRH) , or the like) . A DU may be located at edges of the network with radio frequency (RF) functionality. A DU may be connected to multiple CU-UPs that are connected to (e.g., under the control of) the same CU-CP (e.g., for RAN sharing, radio as a service (RaaS) , and service specific deployments) . DUs may be configured to individually (e.g., dynamic selection) or jointly (e.g., joint transmission) serve traffic to a UE. Each DU 214-216 may be connected with one of AU/RRUs 220-224. The DU may be connected to an AU/RRU via each of the F1-C and F1-U interfaces.

The CU-CP 210 may be connected to multiple DU (s) that are connected to (e.g., under control of) the same CU-UP 212. Connectivity between a CU-UP 212 and a DU may be established by the CU-CP 210. For example, the connectivity between the CU-UP 212 and a DU may be established using Bearer Context Management functions. Data forwarding between CU-UP (s) 212 may be via a Xn-U interface.

The distributed RAN 200 may support fronthauling solutions across different deployment types. For example, the RAN 200 architecture may be based on transmit network capabilities (e.g., bandwidth, latency, and/or jitter) . The distributed RAN 200 may share features and/or components with LTE. For example, AN 208 may support dual connectivity with NR and may share a common fronthaul for LTE and NR. The distributed RAN 200 may enable cooperation between and among DUs 214-218, for example, via the CU-CP 212. An inter-DU interface may not be used.

Logical functions may be dynamically distributed in the distributed RAN 200. As will be described in more detail with reference to FIG. 3, the Radio Resource Control (RRC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, Physical (PHY) layers, and/or Radio Frequency (RF) layers may be adaptably placed, in the N AN and/or UE.

FIG. 3 illustrates a diagram showing examples for implementing a communications protocol stack 300 in a RAN (e.g., such as the RAN 200) , according to aspects of the present disclosure. The illustrated communications protocol stack 300 may be implemented by devices operating in a wireless communication system, such as a 5G NR system (e.g., the wireless communication network 100) . In various examples, the layers of the protocol stack 300 may be implemented as separate modules of software, portions of a processor or ASIC, portions of non-collocated devices connected by a communications link, or various combinations thereof. Collocated and non-collocated implementations may be used, for example, in a protocol stack for a network access device or a UE. As shown in FIG. 3, the system may support various services over one or more protocols. One or more protocol layers of the protocol stack 300 may be implemented by the AN and/or the UE.

As shown in FIG. 3, the protocol stack 300 is split in the AN (e.g., AN 208 in FIG. 2) . The RRC layer 305, PDCP layer 310, RLC layer 315, MAC layer 320, PHY layer 325, and RF layer 530 may be implemented by the AN. For example, the CU-CP (e.g., CU-CP 210 in FIG. 2) and the CU-UP e.g., CU-UP 212 in FIG. 2) each may implement the RRC layer 305 and the PDCP layer 310. A DU (e.g., DUs 214-218 in FIG. 2) may implement the RLC layer 315 and MAC layer 320. The AU/RRU (e.g., AU/RRUs 220-224 in FIG. 2) may implement the PHY layer (s) 325 and the RF layer (s) 330. The PHY layers 325 may include a high PHY layer and a low PHY layer.

The UE may implement the entire protocol stack 300 (e.g., the RRC layer 305, the PDCP layer 310, the RLC layer 315, the MAC layer 320, the PHY layer (s) 325, and the RF layer (s) 330) .

FIG. 4 illustrates example components of BS 110 and UE 120 (as depicted in FIG. 1) , which may be used to implement aspects of the present disclosure. For example, antennas 452,

processors

466, 458, 464, and/or controller/processor 480 of the UE 120 and/or antennas 434,

processors

420, 430, 438, and/or controller/processor 440 of the BS 110 may be used to perform the various techniques and methods described herein with respect to FIGs. 9 and 10.

At the BS 110, a transmit processor 420 may receive data from a data source 412 and control information from a controller/processor 440. The control information may be for the physical broadcast channel (PBCH) , physical control format indicator channel (PCFICH) , physical hybrid ARQ indicator channel (PHICH) , physical downlink control channel (PDCCH) , group common PDCCH (GC PDCCH) , etc. The data may be for the physical downlink shared channel (PDSCH) , etc. The processor 420 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The processor 420 may also generate reference symbols, e.g., for the primary synchronization signal (PSS) , secondary synchronization signal (SSS) , and cell-specific reference signal (CRS) . A transmit (TX) multiple-input multiple-output (MIMO) processor 430 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) 432a through 432t. Each modulator 432 may process a respective output symbol stream (e.g., for OFDM, etc. ) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 432a through 432t may be transmitted via the antennas 434a through 434t, respectively.

At the UE 120, the antennas 452a through 452r may receive the downlink signals from the base station 110 and may provide received signals to the demodulators (DEMODs) in transceivers 454a through 454r, respectively. Each demodulator 454 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc. ) to obtain received symbols. A MIMO detector 456 may obtain received symbols from all the demodulators in transceivers 454a through 454r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 458 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120 to a data sink 460, and provide decoded control information to a controller/processor 480.

On the uplink, at UE 120, a transmit processor 464 may receive and process data (e.g., for the physical uplink shared channel (PUSCH) ) from a data source 462 and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor 480. The transmit processor 464 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS) ) . The symbols from the transmit processor 464 may be precoded by a TX MIMO processor 466 if applicable, further processed by the demodulators in transceivers 454a through 454r (e.g., for SC-FDM, etc. ) , and transmitted to the base station 110. At the BS 110, the uplink signals from the UE 120 may be received by the antennas 434, processed by the modulators 432, detected by a MIMO detector 436 if applicable, and further processed by a receive processor 438 to obtain decoded data and control information sent by the UE 120. The receive processor 438 may provide the decoded data to a data sink 439 and the decoded control information to the controller/processor 440.

The controllers/

processors

440 and 480 may direct the operation at the BS 110 and the UE 120, respectively. The processor 440 and/or other processors and modules at the BS 110 may perform or direct the execution of processes for the techniques described herein. The

memories

442 and 482 may store data and program codes for BS 110 and UE 120, respectively. A scheduler 444 may schedule UEs for data transmission on the downlink and/or uplink.

FIG. 5 illustrates an example system architecture 500 for interworking between 5GS (e.g., such as the distributed RAN 200) and E-UTRAN-EPC, in accordance with certain aspects of the present disclosure. As shown in FIG. 5, the UE 502 may be served by

separate RANs

504A and 504B controlled by

separate core networks

506A and 506B, where the RAN 504A provides E-UTRA services and RAN 504B provides 5G NR services. The UE may operate under only one RAN/CN or both RANs/CNs at a time.

In LTE, the basic transmission time interval (TTI) or packet duration is the 1 ms subframe. In NR, a subframe is still 1 ms, but the basic TTI is referred to as a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, …slots) depending on the subcarrier spacing. The NR RB is 12 consecutive frequency subcarriers. NR may support a base subcarrier spacing of 15 KHz and other subcarrier spacing may be defined with respect to the base subcarrier spacing, for example, 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing.

FIG. 6 is a diagram showing an example of a frame format 600 for NR. The transmission timeline for each of the downlink and uplink may be partitioned into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be partitioned into 10 subframes, each of 1 ms, with indices of 0 through 9. Each subframe may include a variable number of slots depending on the subcarrier spacing. Each slot may include a variable number of symbol periods (e.g., 7 or 14 symbols) depending on the subcarrier spacing. The symbol periods in each slot may be assigned indices. A mini-slot, which may be referred to as a sub-slot structure, refers to a transmit time interval having a duration less than a slot (e.g., 2, 3, or 4 symbols) .

Each symbol in a slot may indicate a link direction (e.g., DL, UL, or flexible) for data transmission and the link direction for each subframe may be dynamically switched. The link directions may be based on the slot format. Each slot may include DL/UL data as well as DL/UL control information.

In NR, a synchronization signal (SS) block is transmitted. The SS block includes a PSS, a SSS, and a two symbol PBCH. The SS block can be transmitted in a fixed slot location, such as the symbols 0-3 as shown in FIG. 6. The PSS and SSS may be used by UEs for cell search and acquisition. The PSS may provide half-frame timing, the SS may provide the CP length and frame timing. The PSS and SSS may provide the cell identity. The PBCH carries some basic system information, such as downlink system bandwidth, timing information within radio frame, SS burst set periodicity, system frame number, etc. The SS blocks may be organized into SS bursts to support beam sweeping. Further system information such as, remaining minimum system information (RMSI) , system information blocks (SIBs) , other system information (OSI) can be transmitted on a physical downlink shared channel (PDSCH) in certain subframes. The SS block can be transmitted up to sixty-four times, for example, with up to sixty-four different beam directions for mmW. The up to sixty-four transmissions of the SS block are referred to as the SS burst set. SS blocks in an SS burst set are transmitted in the same frequency region, while SS blocks in different SS bursts sets can be transmitted at different frequency locations.

In some circumstances, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh, and/or various other suitable applications. Generally, a sidelink signal may refer to a signal communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying that communication through the scheduling entity (e.g., UE or BS) , even though the scheduling entity may be utilized for scheduling and/or control purposes. In some examples, the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum) .

A UE may operate in various radio resource configurations, including a configuration associated with transmitting pilots using a dedicated set of resources (e.g., a radio resource control (RRC) dedicated state, etc. ) or a configuration associated with transmitting pilots using a common set of resources (e.g., an RRC common state, etc. ) . When operating in the RRC dedicated state, the UE may select a dedicated set of resources for transmitting a pilot signal to a network. When operating in the RRC common state, the UE may select a common set of resources for transmitting a pilot signal to the network. In either case, a pilot signal transmitted by the UE may be received by one or more network access devices, such as an AN, or a DU, or portions thereof. Each receiving network access device may be configured to receive and measure pilot signals transmitted on the common set of resources, and also receive and measure pilot signals transmitted on dedicated sets of resources allocated to the UEs for which the network access device is a member of a monitoring set of network access devices for the UE. One or more of the receiving network access devices, or a CU to which receiving network access device (s) transmit the measurements of the pilot signals, may use the measurements to identify serving cells for the UEs, or to initiate a change of serving cell for one or more of the UEs.

Example Polar Codes

Polar codes are a relatively recent breakthrough in coding theory which have been proven to asymptotically (for code size N approaching infinity) achieve the Shannon capacity. Polar codes have many desirable properties such as deterministic construction (e.g., based on a fast Hadamard transform) , very low and predictable error floors, and simple successive-cancellation (SC) based decoding. They are currently being considered as a candidate for error-correction in next-generation wireless systems such as NR.

Polar codes are linear block codes of length N=2 ⁿ where their generator matrix is constructed using the n ^th Kronecker power of the matrix

denoted by G ⁿ. For example, Equation (1) shows the resulting generator matrix for n=3.

According to certain aspects, a codeword may be generated (e.g., by encoder 706) by using the generator matrix to encode a number of input bits consisting of K information bits and N-K “frozen” bits which contain no information and are “frozen” to a known value, such as zero. For example, given a number of input bits u= (u ₀, u ₁, ..., u _N-1) , a resulting codeword vector x= (x ₀ , x ₁, ..., x _N-1) may be generated by encoding the input bits using the generator matrix G. This resulting codeword may then be rate matched and transmitted by a base station over a wireless medium and received by a UE.

When the received vectors are decoded, for example by using a Successive Cancellation (SC) decoder, every estimated bit,

has a predetermined error probability given that bits u ₀ ^i-1 were correctly decoded, that, for extremely large codesize N, tends towards either 0 or 0.5. Moreover, the proportion of estimated bits with a low error probability tends towards the capacity of the underlying channel. Polar codes exploit this phenomenon, called channel polarization, by using the most reliable K bits to transmit information, while setting to a predetermined value (such as 0) , also referred to as freezing, the remaining (N-K) bits, for example as explained below.

Polar codes transform the channel into N parallel “virtual” channels for the N information and frozen bits. If C is the capacity of the channel, then, for sufficiently large values of N, there are almost N*C channels which are extremely reliable and there are almost N (1 –C) channels which are extremely unreliable. The basic polar coding scheme then involves freezing (i.e., setting to a known value, such as zero) the input bits in u corresponding to the unreliable channels, while placing information bits only in the bits of u corresponding to reliable channels. For short-to-medium N, this polarization may not be complete in the sense there could be several channels which are neither completely unreliable nor completely reliable (i.e., channels that are marginally reliable) . Depending on the rate of transmission, bits corresponding to these marginally reliable channels may be either frozen or used for information bits.

Example Flexible Bandwidth Design For Physical Broadcast Channel

When trying to access a cell, the UE may first need to perform a cell synchronization procedure, which allows the UE to acquire the physical cell ID (PCI) , time slot and frame synchronization of the cell, and which will enable UE to read system information blocks from the network of the cell. For example, in some cases, the UE may begin by searching for a primary synchronization signal (PSS) . From the PSS, the UE may determine the physical layer identity of the cell. After receiving the PSS, the UE may then receive the secondary synchronization signal (SSS) , which allows the UE to obtain physical layer cell identity group number. Based on the PSS and the SSS, the UE may then determine the PCI of the cell and may become synchronized with transmissions from the cell.

After the cell synchronization procedure is complete, the UE may proceed with attempting to read the master information block (MIB) of the cell. For example, after the cell synchronization procedure, the UE may search for and decode a physical broadcast channel (PBCH) to receive a master information block (MIB) that contains a number of parameters necessary for accessing the cell.

In Release 15, the PBCH may be encoded using a Polar code, as described above. FIG. 7 illustrates an example encoding process for a PBCH. For example, as illustrated, J information bits to be transmitted on the PBCH may be input into an m-bit outer-code encoder, such as a CRC encoder. The CRC encoder generates m CRC bits (e.g., 24 bits) based on the J information bits, which are then added to the J information bits to form a sequence of bits K (e.g., 40, 72 bits) . The sequence of bits K may then be input into a Polar encoder that uses a Polar code code sequence (e.g., that indicates a reliability of each sub-channel) to encode the sequence of K bits, generating an N-bit polar-encoded codeword (e.g., 512 bits) . Thereafter, sub-block interlacing may be performed on the codeword bits, which may then be stored in an N-bit circular buffer. Rate matching, such as repetition, may then be performed on the stored bits to generate M bits (e.g., 864) for transmission on the PBCH. The M-bits may include the N bits stored in the circular buffer in addition to M-N repetition bits.

FIG. 8 illustrates a current PBCH design for Rel 15. In some cases, a bandwidth for the PSS and SSS may comprise about 11 physical resource block (PRBs) while the bandwidth of the PBCH may comprise 20 PRB. Due to the large number of PRBs that the PBCH channel spans, the PBCH may not be placed within a 5 MHz operating bandwidth with 30k sub-carrier spacing. As a result, certain UEs operating according to a 5 MHz operating bandwidth may not be able to properly decode the PBCH necessary for accessing a cell. For example, as illustrated, the PSS and SSS may be mapped to subcarriers between a and a+Z (e.g., where a= subcarrier 55 and Z=subcarrier 127) , which may be located within the center frequency of a 5 MHz operating bandwidth (e.g., spanning 11 PRBs) . However, as illustrated, due to the large size of the PBCH (e.g., 20PRBs) , M bits for transmission on the PBCH may be mapped to a plurality of subcarriers ranging between 0-X (e.g., where X=239) , which may fall outside the center frequency of the 5 MHz operating bandwidth and result in a PBCH that is not decodable for certain types of devices. Thus, aspects of the present disclosure propose techniques for transmitting a PBCH that may be decodable by devices operating at different operating bandwidths.

FIG. 9 is a flow diagram illustrating example operations 900 for wireless communication, in accordance with certain aspects of the present disclosure. The operations 900 may be performed, for example, by a BS (e.g., such as a BS 110 in the wireless communication network 100) . Operations 900 may be implemented as software components that are executed and run on one or more processors (e.g., processor 440 of FIG. 4) . Further, the transmission and reception of signals by the BS in operations 900 may be enabled, for example, by one or more antennas (e.g., antennas 434 of FIG. 4) . In certain aspects, the transmission and/or reception of signals by the BS may be implemented via a bus interface of one or more processors (e.g., processor 440) obtaining and/or outputting signals.

The operations 900 may begin, at 902, by generating bits of information for transmission on a physical broadcast channel (PBCH) spanning a plurality of subcarriers.

At 904, the base station encodes the bits of information using a polar code.

At 906, the base station maps the encoded bits of information to the plurality of subcarriers and a plurality of symbols, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation.

At 908, the base station transmits the encoded bits of information over the plurality of subcarriers and the plurality of symbols according to the mapping.

FIG. 10 is a flow diagram illustrating example operations 1000 for wireless communication, in accordance with certain aspects of the present disclosure. The operations 1000 may be performed, for example, by UE (e.g., such as a UE 120 in the wireless communication network 100) . The operations 1000 may be complimentary operations by the UE to the operations 900 performed by the BS. Operations 1000 may be implemented as software components that are executed and run on one or more processors (e.g., processor 480 of FIG. 4) . Further, the transmission and reception of signals by the UE in operations 1000 may be enabled, for example, by one or more antennas (e.g., antennas 452 of FIG. 4) . In certain aspects, the transmission and/or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., processor 480) obtaining and/or outputting signals.

The operations 1000 may begin, at 1002, by receiving encoded bits of information transmitted on a physical broadcast channel according to a mapping, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation.

At 1004, the UE decodes the encoded bits of information.

As noted above, the base station may generate bits of information for transmission on a physical broadcast channel (PBCH) spanning a plurality of subcarriers and may encode the bits of information using a polar code. According to aspects, in some cases, the bits of information may comprise system information, such as a master information block (MIB) necessary for accessing the base station. The base station may then map the encoded bits of information to the plurality of subcarriers and a plurality of symbols, such that, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation. In some cases, the second bandwidth mode of operation may be greater than the first bandwidth mode of operation. For example, in some cases, the first bandwidth mode of operation may comprise a 5 megahertz (MHz) bandwidth mode of operation and the second bandwidth mode of operation may comprise a greater-than-5-MHz bandwidth mode of operation (e.g., 20 MHz) . Additionally, it should be understood that the phrases “bandwidth mode of operation” and “operating bandwidth” may generally be used herein interchangeably. For example, the first UE operating according to the first bandwidth mode of operation may be said to be operating according to/within a first operating bandwidth and the second UE operating according to the second bandwidth mode of operation may be said to be operating according to/within a second operating bandwidth.

According to aspects, different mapping techniques may be used to allow devices operating according to varying bandwidths to receive and decode the PBCH (e.g., the encoded bits of information transmitted on the PBCH) . As noted, an advantage to the mapping techniques presented below is that different types of UEs operating according to different bandwidth modes of operation may be able to receive and decode the same PBCH information, thereby reducing complexity and saving resources (e.g., time, frequency, power) within a wireless communications network.

FIG. 11 illustrates one example mapping technique, according to aspects presented herein. For example, as illustrated in FIG. 11, mapping may include mapping a first number of encoded bits to a first set of subcarriers of a plurality of subcarriers. In some cases, the first set of subcarriers falls outside a lower subcarrier bound of a set of subcarriers corresponding to the first bandwidth mode of operation (e.g., the 5 MHz bandwidth mode of operation) . For example, as illustrated in FIG. 11, the first bandwidth mode of operation may be roughly defined as the 12 center PRBs ranging between subcarriers a-8 and a+Z+9, where, in some cases, a is equal to subcarrier 55 and Z is equal to subcarrier 127. That is, for example, the first bandwidth mode of operation may be roughly defined as subcarriers between subcarrier 47 and subcarrier 136. Thus, as illustrated in FIG. 11, the base station may map the first number of encoded bits to subcarriers 1102, which fall outside the lower subcarrier bound of the set of subcarriers corresponding to the first bandwidth mode of operation (e.g., subcarrier a-8) . According to aspects, the first number of encoded bits may also be mapped across one or more symbols of a subframe (e.g., symbols 1-3, as illustrated in FIG. 11) .

It should be understood that, whenever mapped encoded bits of information (or simply mapped bits of information) are described as being mapped to subcarriers outside a lower subcarrier bound or an upper subcarrier bound of the first bandwidth mode of operation, these mapped bits may still be mapped to subcarriers falling within the second bandwidth mode of operation. Thus, for example, while a first UE operating according to the first bandwidth mode of operation may not be able to receive or decode bits mapped to subcarriers outside of the first bandwidth mode of operations, these mapped bits may still be receivable and decodable by at least a second UE operating according to the second bandwidth mode of operation (e.g., which, in some cases, is greater than the first bandwidth mode of operation) .

The base station may also map a second number of encoded bits to a second set of subcarriers that falls within the set of subcarriers corresponding to the first bandwidth mode of operation (e.g., 5 MHz) . For example, as illustrated in FIG. 11, the base station may map the second number of encoded bits to subcarriers 1104, which fall within the set of subcarriers corresponding to the first bandwidth mode of operation (e.g., bounded by and between subcarrier a-8 and subcarrier a+Z+9) . As illustrated, the second number of encoded bits may occupy roughly the same subcarriers as the PSS and SSS signals in one or more symbols of the subframe, such as

symbols

1 and 3.

According to aspects, the base station may also map a third number of encoded bits to a third set of subcarriers of the plurality of subcarriers that falls outside an upper subcarrier bound of the set of subcarriers corresponding to the first bandwidth mode of operation. For example, as illustrated in FIG. 11, the base station may map the third number of encoded bits to subcarriers 1106, which fall outside the upper subcarrier bound of the set of subcarriers corresponding to the first bandwidth mode of operation (e.g., subcarrier a+Z+9) . Like the first number of encoded bits, the third number of encoded bits may be mapped across one or more symbols of the subframe (e.g., symbols 1-3) .

According to aspects, to allow the PBCH to be decodable by devices operating at different operating bandwidths (e.g., a first UE operating at a 5 MHz bandwidth mode of operation and a second UE operating at a greater-than-5-MHz bandwidth mode of operation) , the base station may also copy the first number of encoded bits (e.g., that fall outside the lower bound) and the third number of encoded bits (e.g., that fall outside the upper bound) to a number of symbols in addition to the one or more symbols that are already used for carrying the first number of encoded bits and the third number of encoded bits (e.g., symbols 1-3) . For example, as illustrated in FIG. 11, the base station may copy the first number of encoded bits and third number of encoded bits to subcarriers 1108 that fall within the first operating bandwidth of two additional symbols occurring after the one or more symbols already carrying the first number of encoded bits and the third number of encoded bits, such as

symbols

4 and 5 of the subframe.

According to aspects, by copying the first number of encoded bits and the third number of encoded bits (e.g., that would normally not be receivable/decodable by devices operating according to the first operating bandwidth since they would fall outside the first operating bandwidth) to the subcarriers 1108 that fall within the first operating bandwidth of the two additional symbols (e.g., symbols 4 and 5) , this allows devices operating according to the first operating bandwidth to receive the first number of encoded bits and third number of encoded bits which are necessary for properly decoding the PBCH. Moreover, devices operating according to the second bandwidth mode of operation, which may already be capable of receiving and decoding the first and third number of encoded bits in symbols 1-3 (e.g., that fall outside the upper and lower bounds of the first operating bandwidth) , may additionally use the first number of encoded bits and the third number of encoded bits in the additional symbols (e.g., symbols 4 and 5) to improve decoding of the PBCH (e.g., via combining of the bits of encoded data) .

FIG. 12 illustrates another example mapping technique, according to aspects presented herein. According to aspects, the mapping technique illustrated in FIG. 12 involves pre-freezing (e.g., puncturing) a first set of bits 1202 of size J (e.g., bit indices 0 to J-1) . According to aspects, after pre-freezing the J bits and encoding the bits of information, the encoded bits of information may be stored by the base station in a circular buffer of size N. According to aspects, the stored encoded bits of information (e.g., a fourth set of bits 1204, as described in more detail below) may comprise a size of N-J, accounting for the J punctured bits) . As illustrated, the fourth set of bits may comprise bits with indices in the circular buffer ranging between J-1 and N-1.

The base station may then perform rate matching on the stored encoded bits, such as repetition to increase the size of the stored encoded bits of information from size N to size M (or the size of the information block that needs to be transmitted) . For example, performing repetition on the stored encoded stream of bits may involve generating a second set of bits 1206 of size M-N that comprises repeated bits from the stored encoded bits of information. Thereafter, after performing repetition and to compensate for the pre-frozen bits (e.g., punctured bits) , the base station may generate a third set of bits 1208 by copying J bits of the second set of bits.

According to aspects, the base station may then map the fourth set of bits 1204 (e.g., which comprises a subset of the original polar code used to encode the bits of information) to a first set of subcarriers 1220, spanning one or more symbols (e.g.,

symbols

1 and 3, as illustrated) . According to aspects, the first set of subcarriers 1220 may fall within a set of subcarriers 1222 corresponding to the first bandwidth mode of operation (e.g., 5 MHz bandwidth mode of operation) . For example, in some cases, the set of subcarriers 1222 may include 12 PRBs, ranging between subcarriers a to a+Z, as illustrated in FIG. 12 and described in greater detail above.

In some cases, the mapped fourth set of bits 1204 may comprise a same center frequency as at least one of a PSS or an SSS. Additionally, since the fourth set of bits 1204 comprises a subset of the original polar code, the fourth set of bits 1204 may be independently decodable by devices operating according to the first bandwidth mode of operation, for example, without the need for receiving the encoded bits of information transmitted in subcarriers falling outside the first bandwidth mode of operation, as described in greater detail below.

The base station may also map the second set of bits 1206 and the third set of bits 1208 to at least one of a second set of subcarriers 1224 or a third set of subcarriers 1226, spanning one or more symbols (e.g., symbols 1-3, as illustrated) . In some cases, the second set of subcarriers 1224 may fall outside a lower subcarrier bound (e.g., subcarrier a-8, as described above) of the set of subcarriers 1222 corresponding to the first bandwidth mode of operation. Additionally, the third set of subcarriers 1226 may fall outside an upper subcarrier bound (e.g., subcarrier a+Z+9, as described above) of the set of subcarriers 1222 corresponding to the first bandwidth mode of operation.

According to aspects, while the fourth set of bits 1204 in the first set of subcarriers 1220 may be independently decodable, devices operating according to the second bandwidth mode of operation (e.g., the second UE) may also receive the second set of bits 1206 and the third set of bits 1208 in the second set of subcarriers 1224 and/or the third set of subcarriers 1226 (e.g., in addition to the fourth set of bits 1204 transmitted within the first set of subcarriers 1220 falling within the first bandwidth mode of operation) to improve decoding performance of the encoded bits of information transmitted in the PBCH. Thus, techniques according to this example mapping may allow both the first UE operating according to the first bandwidth mode of operation (e.g., 5 MHz) and the second UE operating according to the second bandwidth mode of operation (e.g., greater than 5 MHz) to receive and decode the PBCH.

FIG. 13 illustrates another example mapping technique, according to aspects presented herein. According to aspects, the mapping technique illustrated in FIG. 13 is similar to the mapping technique described above with respect to FIG. 12. However, instead of mapping the second set of bits 1206 and the third set of bits 1208 to subcarriers falling outside the first bandwidth mode of operation (e.g., 1224 and 1226) , the base station may instead map the second set of bits 1206 and the third set of bits 1208 to the first set of subcarriers 1220 spanning a number of symbols in addition to the one or more symbols to which the fourth set of bits 1204 are mapped to/span. For example, as illustrated, the fourth set of bits 1204 map be mapped to/

span symbols

1 and 3 of a subframe. In this mapping technique, the base station may map the second set of bits 1206 and the third set of bits 1208 to one or more additional symbols in the subframe, such as symbols 4 (e.g., 1302) and 5 (e.g., 1304) , which occur after the symbols to which the fourth set of bits 1204 are mapped (e.g., symbols 1 and 3) , as illustrated.

According to aspects, since all of the encoded bits are transmitted within the first operating bandwidth (e.g., corresponding to the first bandwidth mode of operation) , this mapping technique allows both the first UE operating according to the first bandwidth mode of operation and the second UE operating according to the second bandwidth mode of operation to fully receive all of the encoded bits transmitted on the PBCH, resulting in better decoding performance.

In some cases, another mapping technique may involve a combination of the mapping techniques illustrated in FIGs. 12 and 13. For example, in some cases, the base station may map the second set of bits 1206 and the third set of bits 1208 to the second set of subcarriers 1224 and the third set of subcarriers 1226, while also copying/mapping the second set of bits 1206 and the third set of bits 1208 to the two

additional symbols

1302 and 1304.

More generally, the techniques presented herein minimize the bandwidth required to transmit the PBCH to 12 PRBs (e.g., which is identical to that of the PSS and SSS) without performance loss. The techniques presented herein also supporting soft-combining of multiple transmissions within truncated bandwidth and only require a minor modification on Polar encoder by pre-freezing unfrozen bits [0, J-1] . Additionally, it should be understood that, while the techniques presented herein are described in relation to the PBCH, the techniques presented herein may also apply to any other type of channel that spans more than 12 PRBs but is desired to be transmitted within those 12 center PRBs.

FIG. 14 illustrates a communications device 1400 that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in FIG. 9. The communications device 1400 includes a processing system 1402 coupled to a transceiver 1408. The transceiver 1408 is configured to transmit and receive signals for the communications device 1400 via an antenna 1410, such as the various signals as described herein. The processing system 1402 may be configured to perform processing functions for the communications device 1400, including processing signals received and/or to be transmitted by the communications device 1400.

The processing system 1402 includes a processor 1404 coupled to a computer-readable medium/memory 1412 via a bus 1406. In certain aspects, the computer-readable medium/memory 1412 is configured to store instructions (e.g., computer-executable code) that when executed by the processor 1404, cause the processor 1404 to perform the operations illustrated in FIG. 9, or other operations for performing the various techniques discussed herein for a flexible bandwidth design for a physical broadcast channel. In certain aspects, computer-readable medium/memory 1412 stores code for generating 1414, code for encoding 1416, code for mapping 1418, and code for transmitting 1420. In certain aspects, the processor 1404 has circuitry configured to implement the code stored in the computer-readable medium/memory 1412. The processor 1404 includes circuitry for generating 1422, circuitry for encoding 1424, circuitry for mapping 1426, and circuitry for transmitting 1428.

FIG. 15 illustrates a communications device 1500 that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in FIG. 10. The communications device 1500 includes a processing system 1502 coupled to a transceiver 1508. The transceiver 1508 is configured to transmit and receive signals for the communications device 1500 via an antenna 1510, such as the various signals as described herein. The processing system 1502 may be configured to perform processing functions for the communications device 1500, including processing signals received and/or to be transmitted by the communications device 1500.

The processing system 1502 includes a processor 1504 coupled to a computer-readable medium/memory 1512 via a bus 1506. In certain aspects, the computer-readable medium/memory 1512 is configured to store instructions (e.g., computer-executable code) that when executed by the processor 1504, cause the processor 1504 to perform the operations illustrated in FIG. 10, or other operations for performing the various techniques discussed herein for a flexible bandwidth design for a physical broadcast channel. In certain aspects, computer-readable medium/memory 1512 stores code for receiving 1514 and code for decoding 1516. In certain aspects, the processor 1504 has circuitry configured to implement the code stored in the computer-readable medium/memory 1512. The processor 1504 includes circuitry for receiving 1522 and circuitry for decoding 1524.

The methods disclosed herein comprise one or more steps or actions for achieving the methods. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.

As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .

As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure) , ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information) , accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” Unless specifically stated otherwise, the term “some” refers to one or more. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112 (f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for. ”

The various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component (s) and/or module (s) , including, but not limited to a circuit, an application specific integrated circuit (ASIC) , or processor. Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components with similar numbering.

The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device (PLD) , discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

If implemented in hardware, an example hardware configuration may comprise a processing system in a wireless node. The processing system may be implemented with a bus architecture. The bus may include any number of interconnecting buses and bridges depending on the specific application of the processing system and the overall design constraints. The bus may link together various circuits including a processor, machine-readable media, and a bus interface. The bus interface may be used to connect a network adapter, among other things, to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of a user terminal 120 (see FIG. 1) , a user interface (e.g., keypad, display, mouse, joystick, etc. ) may also be connected to the bus. The bus may also link various other circuits such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further. The processor may be implemented with one or more general-purpose and/or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry that can execute software. Those skilled in the art will recognize how best to implement the described functionality for the processing system depending on the particular application and the overall design constraints imposed on the overall system.

If implemented in software, the functions may be stored or transmitted over as one or more instructions or code on a computer readable medium. Software shall be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media include both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on the machine-readable storage media. A computer-readable storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. By way of example, the machine-readable media may include a transmission line, a carrier wave modulated by data, and/or a computer readable storage medium with instructions stored thereon separate from the wireless node, all of which may be accessed by the processor through the bus interface. Alternatively, or in addition, the machine-readable media, or any portion thereof, may be integrated into the processor, such as the case may be with cache and/or general register files. Examples of machine-readable storage media may include, by way of example, RAM (Random Access Memory) , flash memory, ROM (Read Only Memory) , PROM (Programmable Read-Only Memory) , EPROM (Erasable Programmable Read-Only Memory) , EEPROM (Electrically Erasable Programmable Read-Only Memory) , registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. The machine-readable media may be embodied in a computer-program product.

A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media. The computer-readable media may comprise a number of software modules. The software modules include instructions that, when executed by an apparatus such as a processor, cause the processing system to perform various functions. The software modules may include a transmission module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. By way of example, a software module may be loaded into RAM from a hard drive when a triggering event occurs. During execution of the software module, the processor may load some of the instructions into cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When referring to the functionality of a software module below, it will be understood that such functionality is implemented by the processor when executing instructions from that software module.

Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared (IR) , radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk, and

disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Thus, in some aspects computer-readable media may comprise non-transitory computer-readable media (e.g., tangible media) . In addition, for other aspects computer-readable media may comprise transitory computer-readable media (e.g., a signal) . Combinations of the above should also be included within the scope of computer-readable media.

Thus, certain aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. For example, instructions for performing the operations described herein and illustrated in FIGs. 9 and 10.

Further, it should be appreciated that modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a user terminal and/or base station as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc. ) , such that a user terminal and/or base station can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

A method of wireless communication by a base station (BS) , comprising:

generating bits of information for transmission on a physical broadcast channel (PBCH) spanning a plurality of subcarriers;

encoding the bits of information using a polar code;

mapping the encoded bits of information to the plurality of subcarriers and a plurality of symbols, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation; and

transmitting the encoded bits of information over the plurality of subcarriers and the plurality of symbols according to the mapping.
The method of claim 1, wherein mapping comprises:

mapping a first number of encoded bits to a first set of subcarriers of the plurality of subcarriers, wherein the first set of subcarriers falls outside a lower subcarrier bound of a set of subcarriers corresponding to the first bandwidth mode of operation;

mapping a second number of encoded bits to a second set of subcarriers, wherein the second set of subcarriers falls within the set of subcarriers corresponding to the first bandwidth mode of operation; and

mapping a third number of encoded bits to a third set of subcarriers of the plurality of subcarriers, wherein the third set of subcarriers falls outside an upper subcarrier bound of the set of subcarriers corresponding to the first bandwidth mode of operation.
The method of claim 1, wherein at least one of:

the first set of subcarriers falls within a second set of subcarriers of the plurality of subcarriers corresponding to the second bandwidth mode of operation;

the second set of subcarriers falls also within the second set of subcarriers of the plurality of subcarriers corresponding to the second bandwidth mode of operation; or

the third set of subcarriers falls within the second set of subcarriers of the plurality of subcarriers corresponding to the second bandwidth mode of operation.
The method of claim 2, wherein the first number of encoded bits, the second number of encoded bits, and the third number of encoded bits span one or more symbols.
The method of claim 4, further comprising:

copying the first number of encoded bits and the third number of encoded bits to a number of symbols in addition to the one or more symbols.
The method of claim 5, wherein the number of symbols in addition to the one or more symbols comprise two symbols occurring after the one or more symbols.
The method of claim 1, wherein generating the bits of information further comprises puncturing, from the bits of information, a first set of bits of size J.
The method of claim 7, further comprising:

storing the encoded bits of information in a circular buffer, wherein the stored encoded bits of information have a size N;

performing rate matching on the stored encoded bits of information, wherein performing rate matching comprises performing repetition on the stored encoded bits of information to increase the size of the stored encoded bits of information from size N to size M.
The method of claim 8, wherein performing repetition comprises:

generating a second set of bits of size M-N, wherein the second set of bits comprise repeated bits from the stored encoded bits of information.
The method of claim 9, further comprising;

generating a third set of bits by copying J bits of the second set of bits.
The method of claim 10, wherein the third set of bits compensate for the punctured first set of bits of size J.
The method of claim 10, wherein mapping comprises:

mapping a fourth set of bits to a first set of subcarriers, wherein the first set of subcarriers falls within a set of subcarriers corresponding to the first bandwidth mode of operation.
The method of claim 12, wherein the fourth set of bits comprise bits, corresponding to the stored encoded bits of information, with indices ranging between J-1 and N-1 in the circular buffer.
The method of claim 12, wherein the fourth set of bits comprise bits corresponding to a subset of the polar code.
The method of claim 12, wherein the mapped fourth set of bits have a same center frequency as at least one of a primary synchronization signal or a secondary synchronization signal.
The method of claim 12, wherein mapping further comprises:

mapping the second set of bits and the third set of bits to a second set of subcarriers and a third set of subcarriers, wherein:

the second set of subcarriers falls outside a lower subcarrier bound of a set of subcarriers corresponding to the first bandwidth mode of operation; and

the third set of subcarriers falls outside an upper subcarrier bound of the set of subcarriers corresponding to the first bandwidth mode of operation.
The method of claim 12, wherein the mapped fourth set of bits span one or more symbols.
The method of claim 17, wherein mapping further comprises:

mapping the second set of bits and the third set of bits to the first set of subcarriers, wherein the mapped second set of bits and the mapped third set of bits span a number of symbols in addition to the one or more symbols.
The method of claim 18, wherein the number of symbols in addition to the one or more symbols comprise two symbols occurring after the one or more symbols.
A method of wireless communication by a user equipment (UE) , comprising:

receiving encoded bits of information transmitted on a physical broadcast channel according to a mapping, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation; and

decoding the encoded bits of information.
The method of claim 20, wherein the mapping comprises:

a first number of encoded bits are mapped to a first set of subcarriers of a plurality of subcarriers, wherein the first set of subcarriers falls outside a lower subcarrier bound of a set of subcarriers corresponding to the first bandwidth mode of operation;

a second number of encoded bits are mapped to a second set of subcarriers, wherein the second set of subcarriers falls within the set of subcarriers corresponding to the first bandwidth mode of operation; and

a third number of encoded bits are mapped to a third set of subcarriers of the plurality of subcarriers, wherein the third set of subcarriers falls outside an upper subcarrier bound of the set of subcarriers corresponding to the first bandwidth mode of operation.
The method of claim 21, wherein at least one of:

the first set of subcarriers falls within a second set of subcarriers of the plurality of subcarriers corresponding to the second bandwidth mode of operation;

the second set of subcarriers falls also within the second set of subcarriers of the plurality of subcarriers corresponding to the second bandwidth mode of operation; or

the third set of subcarriers falls within the second set of subcarriers of the plurality of subcarriers corresponding to the second bandwidth mode of operation.
The method of claim 21, wherein the first number of encoded bits, the second number of encoded bits, and the third number of encoded bits span one or more symbols.
The method of claim 23, wherein:

the first number of encoded bits and the third number of encoded bits are copied to a number of symbols in addition to the one or more symbols.
The method of claim 24, wherein the number of symbols in addition to the one or more symbols comprise two symbols occurring after the one or more symbols.
The method of claim 20, wherein:

the encoded bits of information were encoded using a Polar code; and

the mapping comprises:

a first set of encoded bits are mapped to a first set of subcarriers, wherein the first set of subcarriers falls within a set of subcarriers corresponding to the first bandwidth mode of operation, and wherein the first set of encoded bits comprise bits corresponding to a subset of the polar code.
The method of claim 26, wherein the first set of encoded bits have a same center frequency as at least one of a primary synchronization signal or a secondary synchronization signal.
The method of claim 26, wherein the mapping further comprises:

a second set of encoded bits and a third set of encoded bits are mapped to at least one of a second set of subcarriers and a third set of subcarriers, wherein:

the second set of subcarriers falls outside a lower subcarrier bound of a set of subcarriers corresponding to the first bandwidth mode of operation; and

the third set of subcarriers falls outside an upper subcarrier bound of the set of subcarriers corresponding to the first bandwidth mode of operation.
The method of claim 28, wherein:

the second set of encoded bits comprise repeated bits corresponding to the first set of encoded bits; and

the third set of encoded bits comprise copied bits corresponding to the second set of encoded bits.
The method of claim 29, wherein the third set of encoded bits compensate for a plurality of punctured bits.
The method of claim 26, wherein the first set of encoded bits span one or more symbols.
The method of claim 31, wherein the mapping further comprises:

a second set of encoded bits and a third set of encoded bits are mapped to the first set of subcarriers, wherein the mapped second set of bits and the mapped third set of bits span a number of symbols in addition to the one or more symbols.
The method of claim 32, wherein the number of symbols in addition to the one or more symbols comprise two symbols occurring after the one or more symbols.
An apparatus for wireless communication by a base station (BS) , comprising: at least one processor configured to:

generate bits of information for transmission on a physical broadcast channel (PBCH) spanning a plurality of subcarriers;

encode the bits of information using a polar code;

mapping the encoded bits of information to the plurality of subcarriers and a plurality of symbols, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation; and

transmit the encoded bits of information over the plurality of subcarriers and the plurality of symbols according to the mapping; and

a memory coupled with the at least one processor.
An apparatus for wireless communication by a base station (BS) , comprising:

means for generating bits of information for transmission on a physical broadcast channel (PBCH) spanning a plurality of subcarriers;

means for encoding the bits of information using a polar code;

means for mapping the encoded bits of information to the plurality of subcarriers and a plurality of symbols, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation; and

means for transmitting the encoded bits of information over the plurality of subcarriers and the plurality of symbols according to the mapping.
A non-transitory computer readable medium for wireless communication by a base station (BS) , comprising:

instructions that, when executed by at least one processor, cause the at least one processor to:

generate bits of information for transmission on a physical broadcast channel (PBCH) spanning a plurality of subcarriers;

encode the bits of information using a polar code;

mapping the encoded bits of information to the plurality of subcarriers and a plurality of symbols, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation; and

transmit the encoded bits of information over the plurality of subcarriers and the plurality of symbols according to the mapping.
An apparatus for wireless communication by a user equipment (UE) , comprising:

at least one processor configured to:

receive encoded bits of information transmitted on a physical broadcast channel according to a mapping, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation; and

decode the encoded bits of information; and

a memory coupled with the at least one processor.
An apparatus for wireless communication by a user equipment (UE) , comprising:

means for receiving encoded bits of information transmitted on a physical broadcast channel according to a mapping, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation; and

means for decoding the encoded bits of information.
A non-transitory computer-readable medium for wireless communication by a user equipment (UE) , comprising:

instructions that, when executed by at least one processor, cause at least one processor to:

receive encoded bits of information transmitted on a physical broadcast channel according to a mapping, wherein, based on the mapping, the encoded bits of information are decodable by at least a first user equipment operating according to a first bandwidth mode of operation and at least a second user equipment operating according to a second bandwidth mode of operation; and

decode the encoded bits of information.