Physical cell identification channel (PCICH)

Aspects of the present disclosure provide for the transmission of a cell identifier of a serving cell to a user equipment (UE). A Physical Cell Identification Channel (PCICH) is defined for carrying the cell identifier of the serving cell within an uplink-based mobility framework. In some examples, the PCICH may be transmitted in response to a trigger event that requires the user equipment to have knowledge of the cell identifier. For example, the UE may require the cell identifier to demodulate signals received from the serving cell and facilitate transmission and/or reception of user data traffic with the serving cell.

TECHNICAL FIELD

The technology discussed below relates generally to wireless communication systems, and more particularly, to network zones in next generation (5G) wireless networks. Embodiments can provide and enable techniques for identifying the serving cell within a network zone.

BACKGROUND

Mobility management within a wireless communication network is typically implemented using a downlink-based mobility framework in which downlink reference signals are utilized by a user equipment (UE) to select a serving cell to which the UE connects. For example, a UE may receive synchronization signals and system information broadcast by one or more cells and select a serving cell based on the signal strength of the broadcast signals. Once connected to the network through the serving cell, the UE may continue to monitor signals from the serving cell as well as other neighboring cells. If the UE moves from one cell to another, or if the signal quality of a neighboring cell exceeds that of the serving cell for a given amount of time, the UE may undertake a handoff or handover from the serving cell to the neighboring (target) cell. The above-described downlink-based mobility framework places a significant processing burden on the UE to search for neighboring cells, measure the signal strength from neighboring cells and identify a target cell for handover, especially in dense networks with numerous small cells or in high mobility deployments, such as high speed trains.

In next generation (e.g., 5G) wireless communication networks, an uplink-based mobility framework may be available in which uplink reference signals may be utilized by the network to select a serving cell for a UE. The uplink-based mobility framework reduces the amount of processing performed by the UE, hence leading to UE power savings. However, since the UE may be unaware of the cell selection process and may only have knowledge of a zone that the UE is located in, the identity of the serving cell may not be known by the UE.

SUMMARY

Various aspects of the presence disclosure relate to transmission of a cell identifier of a serving cell to a user equipment (UE). A Physical Cell Identification Channel (PCICH) is defined for carrying the cell identifier of the serving cell within an uplink-based mobility framework. In some examples, the PCICH may be transmitted in response to a trigger event that requires the user equipment to have knowledge of the cell identifier. For example, the UE may require the cell identifier to demodulate signals received from the serving cell and facilitate transmission and/or reception of user data traffic with the serving cell.

In one aspect of the disclosure, a method of wireless communication in a wireless communication network is disclosed. The method includes transmitting a synchronization signal within a zone including a plurality of cells to enable a user equipment to synchronize with the zone. The method further includes communicating with the user equipment using a zone identifier of the zone without providing a cell identifier of a serving cell within the zone, and detecting a trigger event that necessitates the user equipment have knowledge of the cell identifier of the serving cell for communication between the user equipment and the serving cell within the zone. The method further includes transmitting a physical cell identification channel (PCICH) to the user equipment in response to the trigger event, where the PCICH includes at least the cell identifier of the serving cell.

Another aspect of the disclosure provides an apparatus in a wireless communication network. The apparatus includes a processor, a transceiver communicatively coupled to the processor, and a memory communicatively coupled to the processor. The processor is configured to transmit a synchronization signal within a zone including a plurality of cells to enable a user equipment to synchronize with the zone, and communicate with the user equipment using a zone identifier of the zone without providing a cell identifier of a serving cell within the zone. The processor is further configured to detect a trigger event that necessitates the user equipment to have knowledge of the cell identifier of the serving cell for communication between the user equipment and the serving cell within the zone, and transmit a physical cell identification channel (PCICH) to the user equipment in response to the trigger event, where the PCICH includes at least the cell identifier of the serving cell.

Examples of additional aspects of the disclosure follow. In some aspects of the disclosure, the PCICH may be transmitted within a downlink-centric slot including at least a downlink common and a downlink data portion. For example, the PCICH may be transmitted within one of the downlink data portion or the downlink common burst of the downlink-centric slot. In some aspects of the disclosure, the PCICH may be transmitted within an uplink-centric slot including at least a downlink common burst and an uplink data portion. For example, the PCICH may be transmitted within the downlink common burst. In some aspects of the disclosure, the PCICH may be transmitted over two or more slots. In some aspects of the disclosure, the PCICH may be repeated over one or more symbols of a slot or over one or more slots.

In some aspects of the disclosure, the method further includes dividing a downlink bandwidth into a plurality of sub-bands, transmitting the PCICH within a subset of the sub-band, and transmitting a signaling message indicating the subset of sub-bands including the PCICH. In some aspects of the disclosure, a cyclic redundancy check (CRC) code may be added to a payload of the PCICH. The payload, including the CRC code, may then be encoded to produce an encoded payload. In some aspects of the disclosure, the PCICH may be multiplexed with one or more additional PCICHs, where each of the additional PCICHs is associated with one or more respective additional user equipment.

In some aspects of the disclosure, the trigger event includes detecting the presence of user data traffic to be transmitted to the user equipment. In some examples, upon transmitting the PCICH, a paging message may be transmitted to the user equipment indicating the presence of user data traffic to be transmitted to the user equipment. In some aspects of the disclosure, the trigger event includes receiving a random access request from the user equipment indicating that the user equipment has user data traffic to transmit. In some examples, upon transmitting the PCICH, a random access response may be transmitted to the user equipment that is scrambled using the cell identifier. In some aspects of the disclosure, the trigger event includes receiving an on-demand system information request from the user equipment. In some examples, upon transmitting the PCICH, a system information response may be transmitted to the user equipment that is scrambled using the cell identifier.

In another aspect of the disclosure, another method of wireless communication in a wireless network is disclosed. The method includes receiving a synchronization signal within a zone including a plurality of cells, synchronizing with the zone utilizing the synchronization signal, and communicating with a serving cell within the zone using a zone identifier of the zone without receiving a cell identifier of the serving cell. Upon occurrence of a trigger event, the method further includes receiving a physical cell identification channel (PCICH) including at least the cell identifier of the serving cell within the zone, and communicating with the serving cell utilizing the cell identifier.

Another aspect of the disclosure provides another apparatus in a wireless communication network. The apparatus includes a processor, a transceiver communicatively coupled to the processor, and a memory communicatively coupled to the processor. The processor is configured to receive a synchronization signal within a zone including a plurality of cells, synchronize with the zone utilizing the synchronization signal, and communicate with a serving cell within the zone using a zone identifier of the zone without receiving a cell identifier of the serving cell. Upon occurrence of a trigger event, the processor is further configured to receive a physical cell identification channel (PCICH) comprising at least the cell identifier of the serving cell within the zone, and communicate with the serving cell utilizing the cell identifier.

Examples of additional aspects of the disclosure follow. In some aspects of the disclosure, the method further includes receiving a paging message indicating the presence of user data traffic to be transmitted, where the presence of user data traffic comprises the trigger event. The method further includes receiving a communication related to the user data traffic, and processing the communication utilizing the cell identifier.

In some aspects of the disclosure, the method further includes receiving a random access response signal in response to transmitting a random access request, where the random access request comprises the trigger event. The method further includes demodulating the random access response signal utilizing the cell identifier.

In some aspects of the disclosure, the method further includes receiving a system information response signal in response to transmitting an on-demand system information request, where the on-demand system information request comprises the trigger event, and demodulating the system information response signal utilizing the cell identifier. In some aspects of the disclosure, the method further includes receiving the PCICH within a subset of a plurality of sub-bands of a downlink bandwidth.

DETAILED DESCRIPTION

The various concepts presented throughout this disclosure may be implemented across a broad variety of telecommunication systems, network architectures, and communication standards. Referring now toFIG. 1, as an illustrative example without limitation, a simplified schematic illustration of an access network100is provided. The access network100may be a next generation (e.g., fifth generation (5G)) access network or a legacy (3G or 4G) access network. In addition, one or more nodes in the access network100may be next generation nodes or legacy nodes.

As used herein, the term legacy access network refers to a network employing a third generation (3G) wireless communication technology based on a set of standards that complies with the International Mobile Telecommunications-2000 (IMT-2000) specifications or a fourth generation (4G) wireless communication technology based on a set of standards that comply with the International Mobile Telecommunications Advanced (ITU-Advanced) specification. For example, some the standards promulgated by the 3rd Generation Partnership Project (3GPP) and the 3rd Generation Partnership Project 2 (3GPP2) may comply with IMT-2000 and/or ITU-Advanced. Examples of such legacy standards defined by the 3rd Generation Partnership Project (3GPP) include, but are not limited to, Long-Term Evolution (LTE), LTE-Advanced, Evolved Packet System (EPS), and Universal Mobile Telecommunication System (UMTS). Additional examples of various radio access technologies based on one or more of the above-listed 3GPP standards include, but are not limited to, Universal Terrestrial Radio Access (UTRA), Evolved Universal Terrestrial Radio Access (eUTRA), General Packet Radio Service (GPRS) and Enhanced Data Rates for GSM Evolution (EDGE). Examples of such legacy standards defined by the 3rd Generation Partnership Project 2 (3GPP2) include, but are not limited to, CDMA2000 and Ultra Mobile Broadband (UMB). Other examples of standards employing 3G/4G wireless communication technology include the IEEE 802.16 (WiMAX) standard and other suitable standards.

As further used herein, the term next generation access network generally refers to a network employing continued evolved wireless communication technologies. This may include, for example, a fifth generation (5G) wireless communication technology based on a set of standards. The standards may comply with the guidelines set forth in the 5G White Paper published by the Next Generation Mobile Networks (NGMN) Alliance on Feb. 17, 2015. For example, standards that may be defined by the 3GPP following LTE-Advanced or by the 3GPP2 following CDMA2000 may comply with the NGMN Alliance 5G White Paper. Standards may also include pre-3GPP efforts specified by Verizon Technical Forum (www.vstgf) and Korea Telecom SIG (www.kt5g.org).

In general, a base station (BS) serves each cell. Broadly, a base station is a network element in a radio access network responsible for radio transmission and reception in one or more cells to or from a UE. A BS may also be referred to by those skilled in the art as a base transceiver station (BTS), a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), an access point (AP), a Node B (NB), an eNode B (eNB), a gNodeB (gNB) or some other suitable terminology.

InFIG. 1, two high-power base stations110and112are shown in cells102and104; and a third high-power base station114is shown controlling a remote radio head (RRH)116in cell106. That is, a base station can have an integrated antenna or can be connected to an antenna or RRH by feeder cables. In the illustrated example, the cells102,104, and106may be referred to as macrocells, as the high-power base stations110,112, and114support cells having a large size. Further, a low-power base station118is shown in the small cell108(e.g., a microcell, picocell, femtocell, home base station, home Node B, home eNode B, etc.) which may overlap with one or more macrocells. In this example, the cell108may be referred to as a small cell, as the low-power base station118supports a cell having a relatively small size. Cell sizing can be done according to system design as well as component constraints. It is to be understood that the access network100may include any number of wireless base stations and cells. Further, a relay node may be deployed to extend the size or coverage area of a given cell. The base stations110,112,114,118provide wireless access points to a core network for any number of mobile apparatuses.

FIG. 1further includes a quadcopter or drone120, which may be configured to function as a base station. That is, 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 base station such as the quadcopter120.

In general, base stations may include a backhaul interface for communication with a backhaul portion of the network. The backhaul may provide a link between a base station and a core network, and in some examples, the backhaul may provide interconnection between the respective base stations. The core network is a part of a wireless communication system that is generally independent of the radio access technology used in the radio access network. Various types of backhaul interfaces may be employed, such as a direct physical connection, a virtual network, or the like using any suitable transport network. Some base stations may be configured as integrated access and backhaul (IAB) nodes, where the wireless spectrum may be used both for access links (i.e., wireless links with UEs), and for backhaul links. This scheme is sometimes referred to as wireless self-backhauling. By using wireless self-backhauling, rather than requiring each new base station deployment to be outfitted with its own hard-wired backhaul connection, the wireless spectrum utilized for communication between the base station and UE may be leveraged for backhaul communication, enabling fast and easy deployment of highly dense small cell networks.

The access network100is illustrated supporting wireless communication for multiple mobile apparatuses. A mobile apparatus is commonly referred to as user equipment (UE) in standards and specifications promulgated by the 3rd Generation Partnership Project (3GPP), but may also be referred to by those skilled in the art as a mobile station (MS), a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT), a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. A UE may be an apparatus that provides a user with access to network services.

Within the access network100, the cells may include UEs that may be in communication with one or more sectors of each cell. For example, UEs122and124may be in communication with base station110; UEs126and128may be in communication with base station112; UEs130and132may be in communication with base station114by way of RRH116; UE134may be in communication with low-power base station118; and UE136may be in communication with mobile base station120. Here, each base station110,112,114,118, and120may be configured to provide an access point to a core network (not shown) for all the UEs in the respective cells.

In another example, a mobile network node (e.g., quadcopter120) may be configured to function as a UE. For example, the quadcopter120may operate within cell102by communicating with base station110. In some aspects of the disclosure, two or more UE (e.g., UEs126and128) may communicate with each other using peer to peer (P2P) or sidelink signals127without relaying that communication through a base station (e.g., base station112).

Unicast or broadcast transmissions of control information and/or traffic information (e.g., user data traffic) from a base station (e.g., base station110) to one or more UEs (e.g., UEs122and124) may be referred to as downlink (DL) transmission, while transmissions of control information and/or traffic information originating at a UE (e.g., UE122) may be referred to as uplink (UL) transmissions. In addition, the uplink and/or downlink control information and/or traffic information may be time-divided into frames, subframes, slots, and/or symbols. As used herein, a symbol may refer to a unit of time that, in an orthogonal frequency division multiplexed (OFDM) waveform, carries one resource element (RE) per sub-carrier. A slot may carry 7 or 14 OFDM symbols. A subframe may refer to a duration of 1 ms. Multiple subframes or slots may be grouped together to form a single frame or radio frame. Of course, these definitions are not required, and any suitable scheme for organizing waveforms may be utilized, and various time divisions of the waveform may have any suitable duration.

The air interface in the access network100may utilize one or more multiplexing and multiple access algorithms to enable simultaneous communication of the various devices. For example, multiple access for uplink (UL) or reverse link transmissions from UEs122and124to base station110may be provided utilizing time division multiple access (TDMA), code division multiple access (CDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), sparse code multiple access (SCMA), single-carrier frequency division multiple access (SC-FDMA), resource spread multiple access (RSMA), or other suitable multiple access schemes. Further, multiplexing downlink (DL) or forward link transmissions from the base station110to UEs122and124may be provided utilizing time division multiplexing (TDM), code division multiplexing (CDM), frequency division multiplexing (FDM), orthogonal frequency division multiplexing (OFDM), sparse code multiplexing (SCM), single-carrier frequency division multiplexing (SC-FDM) or other suitable multiplexing schemes.

In the radio access network100, the ability for a UE to communicate while moving, independent of their location, is referred to as mobility. The various physical channels between the UE and the radio access network are generally set up, maintained, and released under the control of a mobility management entity (MME). In various aspects of the disclosure, an access network100may utilize DL-based mobility or UL-based mobility to enable mobility and handovers (i.e., the transfer of a UE's connection from one radio channel to another). In a network configured for DL-based mobility, during a call with a scheduling entity, or at any other time, a UE may monitor various parameters of the signal from its serving cell as well as various parameters of neighboring cells. Depending on the quality of these parameters, the UE may maintain communication with one or more of the neighboring cells. During this time, if the UE moves from one cell to another, or if signal quality from a neighboring cell exceeds that from the serving cell for a given amount of time, the UE may undertake a handoff or handover from the serving cell to the neighboring (target) cell. For example, UE124may move from the geographic area corresponding to its serving cell102to the geographic area corresponding to a neighbor cell106. When the signal strength or quality from the neighbor cell106exceeds that of its serving cell102for a given amount of time, the UE124may transmit a reporting message to its serving base station110indicating this condition. In response, the UE124may receive a handover command, and the UE may undergo a handover to the cell106.

In a network configured for UL-based mobility, UL reference signals from each UE may be utilized by the network to select a serving cell for each UE. In some examples, the base stations110,112, and114/116may broadcast unified synchronization signals (e.g., unified Primary Synchronization Signals (PSSs), unified Secondary Synchronization Signals (SSSs) and unified Physical Broadcast Channels (PBCH)). The UEs122,124,126,128,130, and132may receive the unified synchronization signals, derive the carrier frequency and slot timing from the synchronization signals, and in response to deriving timing, transmit an uplink pilot or reference signal. The uplink pilot signal transmitted by a UE (e.g., UE124) may be concurrently received by two or more cells (e.g., base stations110and114/116) within the access network100. Each of the cells may measure a strength of the pilot signal, and the access network (e.g., one or more of the base stations110and114/116and/or a central node within the core network) may determine a serving cell for the UE124. As the UE124moves through the access network100, the network may continue to monitor the uplink pilot signal transmitted by the UE124. When the signal strength or quality of the pilot signal measured by a neighboring cell exceeds that of the signal strength or quality measured by the serving cell, the network100may handover the UE124from the serving cell to the neighboring cell, with or without informing the UE124.

FIG. 2is a diagram illustrating a network zone200including a plurality of cells204,206, and208. Each of the cells204,206, and208is served by a respective base station210,212, and214. The network zone200may be a zone associated with at least a portion of the access network100described inFIG. 1. As used herein, the term “zone” refers to a group or combination of cells that function in a coordinated manner and are highly synchronized. As a result of the coordinated operation of the cells in a zone, the synchronization signals are zone-specific. That is, the synchronization signals transmitted (e.g., broadcast) from the zone200are typically single-frequency network (SFN) synchronization signals. As further used herein, the term “single-frequency network” refers to a broadcast network where several transmitters simultaneously send the same signal over the same frequency channel.

In the example shown inFIG. 2, a UE202is located in an overlapping area or region between the network cells204and206. Thus, the UE202in the overlapping area may receive unified synchronization signals from base stations210and212. For example, base station210may generate and transmit (e.g., broadcast), unified synchronization signals, which may include a zone identifier for the network zone200, as well as a nominal tone spacing being used by zone200. Similarly, base station212may transmit (e.g., broadcast) the same unified synchronization signals that identify zone200.

After receiving the unified synchronization signals, the UE202in the overlapping area may process the unified synchronization signals to synchronize with the zone200using the nominal tone spacing. The UE202may then transmit a pilot or reference signal, which may be concurrently received by base stations210and212within the zone200. Each of the base stations210and212may measure a strength of the pilot signal, and the zone200(e.g., one or more of the base stations210and212and/or a central node within the core network (not shown)) may determine the serving cell for the UE202. For example, the serving cell may be cell206.

As described above, the unified synchronization signals may identify the zone, but may not identify the cell from which the signal is transmitted. There may be situations, however, where the UE202may require knowledge of the cell identifier of a serving cell. In some examples, the downlink channels (e.g., Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH)) utilized to carry control information and user data traffic to the UE202may be scrambled using the cell identifier of the serving cell206. Thus, in accordance with various aspects of the present disclosure, in order to demodulate the PDCCH and PDSCH, the UE may be provided with the cell identifier of the serving cell206prior to receiving the PDCCH and/or PDSCH.

For example, when the UE202has user data traffic to transmit to the base station210, the UE202may transmit a random access request to set up a connection with the base station210. The base station210may then assign uplink resources to the UE202and transmit the uplink resource assignment information to the UE202on the PDCCH. The base station210may further transmit a random access response to the UE202on the PDSCH. Similarly, when the base station210has user data traffic to be transmitted to the UE202, the base station210may page the UE202using, for example, a Keep Alive message. Upon receiving a response from the UE202, the base station210may allocate downlink resources to the UE202for the downlink user data traffic transmission and transmit the allocated downlink resource information to the UE202on the PDCCH. The downlink user data traffic may then be transmitted by the base station210on the PDSCH.

In addition, in 5G networks, system information may be transmitted to UEs202on-demand (e.g., in response to a UE202transmitting a system information request), thus enabling the network to forego broadcasting the system information and enabling the network to conserve power. For example, the UE202may transmit a system information request, and in response, the base station210may transmit a system information response, such as a Master Information Block (MIB) and/or one or more System Information Blocks (SIBs), on the PDSCH.

To enable the UE202to decode the PDCCH and PDSCH, the base station210may transmit the cell identifier of the serving cell206to the UE202prior to transmitting the PDCCH and/or PDSCH. In accordance with various aspects of the present disclosure, the cell identifier may be transmitted on a new channel, referred to herein as the Physical Cell Identification Channel (PCICH). In some examples, the PCICH may transmitted based on the occurrence of a trigger event detected at the base station210. By way of example, but not limitation, as described above, the trigger event may include reception of a random access request from the UE202, reception of user data traffic to be transmitted to the UE202and/or reception of a system information request from the UE202.

FIG. 3is a conceptual diagram illustrating an example of a hardware implementation for an exemplary base station300employing a processing system314. For example, the base station300may be a next generation (5G) base station as illustrated in any one or more ofFIGS. 1 and 2.

The base station300may be implemented with a processing system314that includes one or more processors304. Examples of processors304include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. In various examples, the base station300may be configured to perform any one or more of the functions described herein. That is, the processor304, as utilized in a base station300, may be used to implement any one or more of the processes described below.

In this example, the processing system314may be implemented with a bus architecture, represented generally by the bus302. The bus302may include any number of interconnecting buses and bridges depending on the specific application of the processing system314and the overall design constraints. The bus302communicatively couples together various circuits including one or more processors (represented generally by the processor304), a memory305, and computer-readable media (represented generally by the computer-readable medium306). The bus302may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further. A bus interface308provides an interface between the bus302and a transceiver310. The transceiver310provides a means for communicating with various other apparatus over a transmission medium (e.g., air interface). Depending upon the nature of the apparatus, a user interface312(e.g., keypad, display, speaker, microphone, joystick) may also be provided.

The processor304is responsible for managing the bus302and general processing, including the execution of software stored on the computer-readable medium306. The software, when executed by the processor304, causes the processing system314to perform the various functions described below for any particular apparatus. The computer-readable medium306and the memory305may also be used for storing data that is manipulated by the processor304when executing software.

In some aspects of the disclosure, the processor304may include circuitry configured for various functions. For example, the processor304may include resource assignment and scheduling circuitry341, configured to generate, schedule, and modify a resource assignment or grant of time-frequency resources. For example, the resource assignment and scheduling circuitry341may schedule time-frequency resources within a plurality of time division duplex (TDD) and/or frequency division duplex (FDD) subframes or slots to carry user data traffic and/or control information to and/or from multiple UEs. The resource assignment and scheduling circuitry341may further operate in coordination with resource assignment and scheduling software351.

The processor304may further include downlink (DL) traffic and control channel generation and transmission circuitry342, configured to generate and transmit downlink traffic and control channels within one or more subframes or slots. The DL traffic and control channel generation and transmission circuitry342may operate in coordination with the resource assignment and scheduling circuitry341to place the DL user data traffic and/or control information onto a time division duplex (TDD) or frequency division duplex (FDD) carrier by including the DL user data traffic and/or control information within one or more subframes or slots in accordance with the resources assigned to the DL user data traffic and/or control information.

For example, the DL traffic and control channel generation and transmission circuitry342may be configured to generate a Keep Alive message (e.g., paging message) for a particular UE to indicate the base station has user data traffic to be transmitted to the UE. The DL traffic and control channel generation and transmission circuitry342may further be configured to generate a communication related to the user data traffic to be transmitted. For example, the DL traffic and control channel generation and transmission circuitry342may be configured to generate a physical downlink control channel (PDCCH) (or Enhanced PDCCH (ePDCCH)) including downlink control information (DCI). In some examples, the DCI may include an assignment of downlink resources for the user data traffic. In addition, the DL traffic and control channel generation and transmission circuitry342may further be configured to generate a physical downlink shared channel (PDSCH) (or Enhanced PDSCH (ePDSCH)) including the downlink user data traffic.

The PDCCH may also include, for example, control information indicating a grant of uplink resources for a particular UE in response to receiving a random access request. The PDSCH may also include, for example, a random access response to the random access request received from a particular UE. The PDSCH may further include, for example, a Master Information Block (MIB) and/or one or more System Information Blocks (SIBs) in response to an on-demand system information request from a particular UE. In some examples, the DL traffic and control channel generation and transmission circuitry342may further scramble the PDCCH and/or PDSCH with the cell identifier of the cell served by the base station300. The DL traffic and control channel generation and transmission circuitry342may further operate in coordination with DL traffic and control channel generation and transmission software352.

The processor304may further include uplink (UL) traffic and control channel reception and processing circuitry343, configured to receive and process uplink control channels and uplink traffic channels from one or more UEs. For example, the UL traffic and control channel reception and processing circuitry343may be configured to receive random access requests from one or more UEs, where the random access requests are configured to request a grant of time-frequency resources for uplink user data transmissions. The UL traffic and control channel reception and processing circuitry343may further be configured to receive on-demand system information requests from one or more UEs. In some examples, a random access request and/or an on-demand system information request may be received in an uplink chirp message from a particular UE. The chirp message may include, for example, a chirp purpose indicator to identify a purpose or functionality of the chirp message. For example, the chirp purpose indicator may indicate that the chirp message is related to one of requesting system information, initiating a random access procedure or other purpose.

In general, the UL traffic and control channel reception and processing circuitry343may operate in coordination with the resource assignment and scheduling circuitry341to schedule UL user data traffic transmissions, DL user data traffic transmissions and/or DL user data traffic retransmissions in accordance with the received UL information. The UL traffic and control channel reception and processing circuitry343may further operate in coordination with UL traffic and control channel reception and processing software353.

The processor304may further include PCICH trigger detection circuitry344, configured to detect the occurrence of a trigger event for generating and transmitting the PCICH including the cell identifier of the cell served by the base station300to one or more UEs. In some examples, the trigger event may include detecting the presence of user data traffic to be transmitted to a UE and/or transmitting a paging message (e.g., a Keep Alive message) to the UE indicating the presence of user data traffic to be transmitted to the UE. In other examples, the trigger event may include receiving a random access request from a UE indicating that the UE has user data traffic to transmit to the base station300. In still other examples, the trigger event may include receiving an on-demand system information request from a UE. The PCICH trigger detection circuitry344may further operate in coordination with PCICH trigger detection software354.

The processor304may further include PCICH generation circuitry345, configured to generate the PCICH for one or more UEs in response to the PCICH trigger detection circuitry344detecting the occurrence of a trigger event. In some examples, upon detecting a trigger event, the PCICH trigger detection circuitry344may request resources for the PCICH from the resource assignment and scheduling circuitry341and instruct the PCICH generation circuitry345to generate the PCICH for a particular UE (e.g., a unicast PCICH). The PCICH generation circuitry345may then generate the PCICH including the cell identifier of the serving cell and provide the PCICH to the DL traffic and control channel generation and transmission circuitry342to place the PCICH within one or more subframes or slots in accordance with the resources assigned to the PCICH. In some examples, the PCICH may be self-contained within a single subframe or slot. In other examples, the PCICH may be transmitted across two or more subframes or slots.

In some examples, the assigned resources for the PCICH may include one or more sub-bands within a downlink bandwidth utilized for transmission of a subframe or slot. For example, the downlink bandwidth may be divided into a plurality of sub-bands, where each sub-band includes a set of contiguous time-frequency resources. The PCICH may be transmitted over all of the sub-bands or only a subset of the sub-bands.

In some examples, a UE may have access to only part of the system downlink bandwidth due to hardware constraints and/or power savings requirements of the UE. For example, if the downlink bandwidth is 100 MHz, and the UE only has the capability to access 20 MHz, the UE may signal the UE bandwidth constraints to the base station300. The PCICH may then be transmitted within a subset of the sub-bands that spans a bandwidth less than or equal to the 20 MHz bandwidth of the UE.

In some examples, the PCICH may be separately transmitted within each sub-band to ensure that each UE may be able to receive the PCICH regardless of the UE constraints. In other examples, the PCICH may be transmitted within one or more pre-configured sub-bands of the downlink bandwidth. In addition, the Keep Alive message (e.g., paging message) transmitted by the DL traffic and control channel generation and transmission circuitry342may further be transmitted within one or more pre-configured sub-bands of the downlink bandwidth.

The PCICH may further be repeated or retransmitted over one or more subframes or slots and/or one or more symbols of the same subframe or slot. For example, the PCICH may be initially transmitted within a first subframe or slot and then repeated within at least a second subframe or slot. Similarly, the PCICH may be initially transmitted within a first symbol of a first subframe or slot and then repeated within at least a second symbol of the first subframe or slot. The number of repeated transmissions may be pre-configured or may be determined based on acknowledgement information received from the UE.

In some examples, the PCICH generation circuitry345may generate a respective PCICH for each of a plurality of UEs and provide the generated PCICHs to the DL traffic and control channel generation and transmission circuitry342. The DL traffic and control channel generation and transmission circuitry342may then multiplex each of the PCICHs using, for example, code division multiplexing, frequency division multiplexing, time division multiplexing, or a hybrid thereof.

The PCICH generation circuitry345may further be configured to add a cyclic redundancy check (CRC) code to a payload of the PCICH and then encode the payload including the CRC code to produce an encoded payload. For example, the PCICH payload may be encoded using, for example, convolutional coding, turbo coding, polar coding, etc. The specific configuration, pre-configured number and/or location of retransmissions, and/or pre-configured sub-bands for transmission of the PCICH may be signaled, for example, within system information (e.g., MIB and/or SIB) to the UE.

In some examples, the PCICH numerology may be nominal (e.g., use the same numerology as other control and/or traffic channels). For example, the PCICH may include the same subcarrier spacing, cyclic prefix, symbol duration, Fast Fourier Transform (FFT) size, etc.

In examples in which the PCICH is unicast to the UE, the PCICH may further be scrambled using the identity of the UE (UE-ID). In some examples, both a Downlink Modulation Reference Signal (DMRS) utilized by the UE to demodulate the PCICH and the PCICH may be scrambled by the UE-ID. The PCICH generation circuitry345may further operate in coordination with PCICH generation software355.

FIG. 4is a conceptual diagram illustrating an example of a hardware implementation for an exemplary UE400employing a processing system414. For example, the UE400may be a UE as illustrated in any one or more ofFIGS. 1 and 2.

The processing system414may be substantially the same as the processing system314illustrated inFIG. 3, including a bus interface408, a bus402, memory405, a processor404, and a computer-readable medium406. Furthermore, the UE400may include a user interface412and a transceiver410substantially similar to those described above inFIG. 3. That is, the processor404, as utilized in a UE400, may be used to implement any one or more of the processes described below.

In some aspects of the disclosure, the processor404may include uplink (UL) traffic and control channel generation and transmission circuitry442, configured to generate and transmit uplink user data traffic on an UL traffic channel, and to generate and transmit uplink control/feedback/acknowledgement information on an UL control channel. For example, the UL traffic and control channel generation and transmission circuitry442may be configured to generate and transmit random access request indicating the UE400has uplink user data traffic to transmit. In another example, the UL traffic and control channel generation and transmission circuitry442may be configured to generate and transmit an on-demand system information request. In some examples, the UL traffic and control channel generation and transmission circuitry442may be configured to generate a chirp message including the random access request or the system information request. The UL traffic and control channel generation and transmission circuitry442may further be configured to generate a pilot (or reference) signal to enable the network to select a serving cell/base station for the UE. The UL traffic and control channel generation and transmission circuitry442may operate in coordination with UL traffic and control channel generation and transmission software452.

The processor404may further include downlink (DL) traffic and control channel reception and processing circuitry444, configured for receiving and processing downlink user data traffic on a traffic channel, and to receive and process control information on one or more downlink control channels. For example, the DL traffic and control channel reception and processing circuitry444may be configured to receive downlink control information (DCI) indicating an assignment of downlink resources or a grant of uplink resources within a PDCCH, system information or a random access response within a PDSCH and downlink user data traffic within a PDSCH. The DL traffic and control channel reception and processing circuitry444may further be configured to receive a Downlink Modulation Reference Signal (DMRS), which may be scrambled with the UE-ID. In some examples, the received downlink user data traffic and/or control information may be temporarily stored in a data buffer415within memory405. The DL traffic and control channel reception and processing circuitry444may be further configured to receive unified synchronization signals from a zone of cells and process the unified synchronization signals to synchronize with the zone. The DL traffic and control channel reception and processing circuitry444may operate in coordination with DL traffic and control channel reception and processing software454.

The processor404may further include PCICH reception and processing circuitry446, configured to receive a PCICH including a cell identifier of the serving cell. In some examples, the PCICH may be self-contained within a single subframe or slot. In other examples, the PCICH may be transmitted across two or more subframes or slots.

The PCICH reception and processing circuitry446may further be configured to decode the PCICH (e.g., based on the received DMRS) to obtain the cell identifier and provide the cell identifier to the DL traffic and control channel reception and processing circuitry444. The DL traffic and control channel reception and processing circuitry may then utilize the cell identifier to demodulate various signals, such as PDCCH and/or PDSCH signals, received from the serving cell. For example, the DL traffic and control channel reception and processing circuitry444may be configured to demodulate a PDSCH carrying a system information response or a random access response from the serving cell utilizing the cell identifier. In another example, the DL traffic and control channel reception and processing circuitry444may be configured to demodulate a PDCCH carrying downlink control information (DCI) indicating an assignment of downlink resources for downlink user data traffic and a PDSCH containing the downlink user data traffic from the serving cell utilizing the cell identifier. Similarly, the DL traffic and control channel reception and processing circuitry444may be configured to demodulate a PDCCH carrying a grant of uplink resources for the UE400to transmit uplink user data traffic utilizing the cell identifier.

The PCICH reception and processing circuitry446may further be configured to monitor one or more sub-bands of the system downlink bandwidth for the PCICH. In addition, the PCICH reception and processing circuitry446may be configured to monitor at least one of the sub-bands over a listening window to increase the likelihood that the UE202will correctly receive the PCICH (e.g., the initial PCICH and/or one or more repeated/retransmitted PCICHs). The PCICH reception and processing circuitry446may further be configured to decode the PCICH based on the type of coding utilized (e.g., convolutional coding, turbo coding, polar coding, etc.) and process an attached CRC code to ensure the PCICH is correctly received. The PCICH reception and processing circuitry446may further operate in coordination with PCICH reception and processing software456.

FIG. 5is a signaling diagram illustrating exemplary signaling for a UE202to perform a random access procedure with a serving base station (BS)210according to some embodiments. The UE202may correspond, for example, to any of the UEs illustrated inFIGS. 1, 2, and/or4. The BS210may correspond, for example, to any of the base stations illustrated inFIGS. 1, 2, and/or3.

In the example, shown inFIG. 5, at502, the UE202may first receive unified synchronization signals of a zone from the BS210. For example, upon powering on, the UE202may listen to synchronization and/or broadcast channels to obtain the synchronization information necessary for initial access to the zone. Examples of synchronization information include, but are not limited to, one or more of downlink system bandwidth/carrier frequency, a Physical Hybrid ARQ Indicator Channel structure, the most significant eight-bits of the System Frame Number, a master information block (MIB), etc. In some examples, the synchronization and/or broadcast channels may include the Primary Synchronization Signal (PSS), the Secondary Synchronization Signal (SSS), and/or the Physical Broadcast Channel (PBCH).

Upon receiving the unified synchronization signals from the BS210, at504, the UE202may acquire timing of the zone and synchronize with the zone. At506, when the UE202detects the presence of user data traffic to be transmitted to the BS210, the UE202may transmit a random access request. For example, the UE202may generate and transmit a chirp signal including a random access chirp purpose indicator to request uplink resources to transmit the user data traffic.

Upon receiving the random access request, at508, the BS210triggers the generation and transmission of the PCICH to the UE202. The PCICH includes the cell identifier of the cell served by the BS210. At510, the BS210may transmit a PDCCH including a grant of uplink resources for transmission of the user data traffic and a PDSCH including a random access response. In some examples, the PDCCH and/or PDSCH (e.g., the random access response) may be scrambled using the cell identifier. The UE202may utilize the cell identifier obtained from the PCICH to demodulate the PDCCH and PDSCH.

FIG. 6is a signaling diagram illustrating exemplary signaling for a UE202to receive on-demand system information from a serving base station210according to some embodiments. The UE202may correspond, for example, to any of the UEs illustrated inFIGS. 1, 2, and/or4. The BS210may correspond, for example, to any of the base stations illustrated inFIGS. 1, 2, and/or3.

In the example, shown inFIG. 6, at602, the UE202may first receive unified synchronization signals of a zone from the BS210. For example, upon powering on, the UE202may listen to synchronization and/or broadcast channels to obtain the synchronization information necessary for initial access to the zone. Examples of synchronization information include, but are not limited to, one or more of downlink system bandwidth/carrier frequency, a Physical Hybrid ARQ Indicator Channel structure, the most significant eight-bits of the System Frame Number, a master information block (MIB), etc. In some examples, the synchronization and/or broadcast channels may include the Primary Synchronization Signal (PSS), the Secondary Synchronization Signal (SSS), and/or the Physical Broadcast Channel (PBCH).

Upon receiving the unified synchronization signals from the BS210, at604, the UE202may acquire timing of the zone and synchronize with the zone. At606, the UE202may transmit a system information request to the BS210to request, for example, a MIB and/or one or more SIBs. In some examples, the UE202may transmit a chirp signal including a system information chirp purpose indicator to request the MIB and/or SIBs from the BS210.

Upon receiving the system request, at608, the BS210triggers the generation and transmission of the PCICH to the UE202. The PCICH includes the cell identifier of the cell served by the BS210. At610, the BS210may transmit a PDCCH and/or PDSCH including a system information response (e.g., the requested MIB and/or SIB s). In some examples, the PDCCH and/or PDSCH (e.g., the system information response) may be scrambled using the cell identifier. The UE202may utilize the cell identifier obtained from the PCICH to demodulate the PDCCH and/or PDSCH.

FIG. 7is a signaling diagram illustrating exemplary signaling for a base station (BS)210to page and transmit user data traffic to a UE202according to some embodiments. The UE202may correspond, for example, to any of the UEs illustrated inFIGS. 1, 2, and/or4. The BS210may correspond, for example, to any of the base stations illustrated inFIGS. 1, 2, and/or3.

In the example, shown inFIG. 7, at702, the UE202may first receive unified synchronization signals of a zone from the BS210. For example, upon powering on, the UE202may listen to synchronization and/or broadcast channels to obtain the synchronization information necessary for initial access to the zone. Examples of synchronization information include, but are not limited to, one or more of downlink system bandwidth/carrier frequency, a Physical Hybrid ARQ Indicator Channel structure, the most significant eight-bits of the System Frame Number, a master information block (MIB), etc. In some examples, the synchronization and/or broadcast channels may include the Primary Synchronization Signal (PSS), the Secondary Synchronization Signal (SSS), and/or the Physical Broadcast Channel (PBCH).

Upon receiving the unified synchronization signals from the BS210, at704, the UE202may acquire timing of the zone and synchronize with the zone. At706, the BS210may detect the presence of downlink user data traffic to be transmitted to the UE202and transmit a Keep Alive (e.g., paging) message to the UE indicating the presence of the downlink user data traffic. Upon detecting the downlink user data traffic and transmitting the Keep Alive page message, at708, the BS210triggers the generation and transmission of the PCICH to the UE202. The PCICH includes the cell identifier of the cell served by the BS210. At710, the BS210may transmit a PDCCH including an assignment of resources for the downlink user data traffic and a PDSCH including the downlink user data traffic. The UE202may utilize the cell identifier obtained from the PCICH to demodulate the PDCCH and PDSCH.

FIG. 8illustrates a structure of a downlink-centric (DL-centric) slot800including a Physical Cell Identification Channel (PCICH)810according to some embodiments. The DL-centric slot is referred to as a DL-centric slot because a majority (or, in some examples, a substantial portion) of the slot includes DL user data traffic. In the example shown inFIG. 8, time is illustrated along a horizontal axis, while frequency is illustrated along a vertical axis. The time-frequency resources of the DL-centric slot500may be divided into a DL common burst802, a DL data portion804and an UL common burst808.

The DL common burst802may exist in the initial or beginning portion of the DL-centric slot. The DL common burst802may include any suitable DL information in one or more channels. In some examples, the DL common burst802may include various scheduling information and/or control information corresponding to various portions of the DL-centric slot. In some configurations, the DL common burst802may be a physical DL control channel (PDCCH). The DL-centric slot may also include a DL data portion804. The DL data portion804may sometimes be referred to as the payload of the DL-centric slot. The DL data portion804may include the communication resources utilized to communicate DL user data traffic from the base station to the UE. In some configurations, the DL data portion804may be a physical DL shared channel (PDSCH).

The UL common burst808may include any suitable UL information in one or more channels. In some examples, the UL common burst808may include feedback information corresponding to various other portions of the DL-centric slot. For example, the UL common burst808may include feedback information corresponding to the DL common burst802and/or DL data portion804. Non-limiting examples of feedback information may include an ACK signal, a NACK signal, a HARQ indicator, and/or various other suitable types of information. The UL common burst808may include additional or alternative information, such as information pertaining to random access channel (RACH) procedures, scheduling requests (SRs), and various other suitable types of information.

As illustrated inFIG. 8, the end of the DL data portion804may be separated in time from the beginning of the UL common burst808. This time separation may sometimes be referred to as a gap, a guard period, a guard interval, and/or various other suitable terms, hereinafter referred to as a guard period (GP)806. This separation provides time for the switch-over from DL communication (e.g., reception operation by the UE to UL communication (e.g., transmission by the UE). One of ordinary skill in the art will understand that the foregoing is merely one example of a DL-centric slot and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

In accordance with various aspects of the present disclosure, the DL data portion804may further be used to transmit the PCICH810. While the illustration inFIG. 8provides the PCICH810as a contiguous block extending across most or all of the DL data portion804in the time dimension, it is to be understood that this is not necessarily the case, and any suitable number of PCICH transmissions may be included in the DL data portion804. For example, the PCICH may be transmitted within one symbol of the DL data portion804, and then may be repeated within one or more additional symbols of the DL data portion804.

In some examples, the PCICH may be transmitted within only a portion of the downlink bandwidth (frequencies) of the slot. For example, the PCICH may be transmitted within a subset of a plurality of sub-bands spanning the downlink bandwidth in the frequency domain. In other examples, the PCICH may be transmitted across all sub-bands of the downlink bandwidth. In some examples, the PCICH may be separately transmitted within each sub-band to ensure that each UE may be able to receive the PCICH regardless of the UE constraints.

FIG. 9illustrates another structure of a downlink-centric (DL-centric) slot900including the PCICH810according to some embodiments. In the DL-centric slot900shown inFIG. 9, the structure again includes the DL common burst802, DL data portion804, GP806and UL common burst808. However, instead of including the PCICH in the DL data portion804, the PCICH810may be included in the DL common burst802. In some examples, the PCICH may be transmitted within one or more symbols of the DL common burst802, and then may be repeated within one or more additional symbols of the DL common burst802and/or one or more additional symbols of the DL data portion804. In addition, the PCICH may be transmitted across all of the sub-bands of the downlink bandwidth or within a subset of a plurality of sub-bands of the downlink bandwidth.

FIG. 10illustrates a structure of an uplink-centric (UL-centric) slot1000including the PCICH according to some embodiments. The UL-centric slot is referred to as a UL-centric slot because a majority (or, in some examples, a substantial portion) of the slot includes UL user data traffic. In the example shown inFIG. 10, time is illustrated along a horizontal axis, while frequency is illustrated along a vertical axis. The time-frequency resources of the UL-centric slot1000may be divided into a DL common burst1002, an UL data portion1006and an UL common burst1008.

The DL common burst1002may exist in the initial or beginning portion of the UL-centric slot. The DL common burst1002inFIG. 10may be similar to the DL common burst802described above with reference toFIG. 8. The UL-centric slot may also include an UL data portion1006. The UL data portion1006may sometimes be referred to as the payload of the UL-centric slot. The UL data portion1006may include the communication resources utilized to communicate UL user data traffic from the UE to the base station. In some configurations, the UL data portion1006may be a physical UL shared channel (PUSCH). As illustrated inFIG. 10, the end of the DL common burst1002may be separated in time from the beginning of the UL data portion1006. This time, separation may sometimes be referred to as a gap, guard period, guard interval, and/or various other suitable terms, hereinafter referred to as a guard period (GP)1004. This separation provides time for the switch-over from DL communication (e.g., reception operation by the UE) to UL communication (e.g., transmission by the UE).

The UL common burst1008inFIG. 10may be similar to the UL common burst808described above with reference toFIG. 8. The UL common burst1008may additionally or alternatively include information pertaining to channel quality indicator (CQI), sounding reference signals (SRSs), and various other suitable types of information. One of ordinary skill in the art will understand that the foregoing is merely one example of an UL-centric slot, and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

In accordance with various aspects of the present disclosure, the DL common burst1002may further be used to transmit the PCICH810. Similar to the above example ofFIG. 8, in the examples ofFIGS. 9 and 10, the location of the PCICH, and the number of PCICH transmissions in a given DL common burst802may be selected for a given implementation, and the illustrated examples ofFIGS. 9 and 10is not intended to be limiting.

In some examples, the PCICH810may be carried within both DL-centric slots (e.g., as shown inFIG. 8 or 9) and UL-centric slots. For example, the PCICH810may be transmitted across two or more DL-centric slots, two or more UL-centric slots or a combination of DL-centric and UL-centric slots. The PCICH810may also be repeated within both DL-centric and UL-centric slots. For example, the PCICH may initially be carried within a DL-centric slot or UL-centric slot and then repeated (retransmitted) in one or more additional DL-centric slots and/or UL-centric slots to increase the likelihood that the UE correctly receives the PCICH. In addition, the UE may transmit an ACK/NACK signal to the BS in the UL common burst of a DL-centric slot or UL-centric slot to indicate whether the PCICH was correctly received. Retransmissions of the PCICH may therefore be determined based on the ACK/NACK signal (e.g., if a NACK is received, the BS may schedule a retransmission of the PCICH).

FIG. 11is a flow chart illustrating an exemplary process1100for providing a cell identifier in a wireless communication network according to some embodiments. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, the process1100may be carried out by the base station illustrated inFIG. 3. In some examples, the process1100may be carried out by any suitable apparatus or means for carrying out the functions or algorithm described below.

At block1102, the base station (BS) may transmit unified synchronization signals within a zone associated with the base station. A UE may then utilize the unified synchronization signals to synchronize with the zone. For example, the DL traffic and control channel generation and transmission circuitry342shown and described above in reference toFIG. 3may transmit the unified synchronization signals.

At block1104, the BS may determine whether a trigger event requiring the UE to have knowledge of the cell identifier of the cell served by the BS has occurred. For example, the BS may determine whether the BS has received downlink user data traffic for transmission to the UE, whether the BS has received a system information request from the UE or whether the BS has received a random access request from the UE. For example, the PCICH trigger detection circuitry344shown and described above in reference toFIG. 3may determine whether a trigger event has occurred.

If a trigger event has occurred (Y branch of1104), at block1106, the BS may generate a Physical Cell Identification Channel (PCICH) including the cell identifier, and at block1108, transmit the PCICH to the UE. For example, the PCICH generation circuitry345shown and described above in reference toFIG. 3may generate the PCICH and the DL traffic and control channel generation and transmission circuitry342shown and described above in reference toFIG. 3may transmit the PCICH to the UE.

FIG. 12is a flow chart illustrating an exemplary process1200for providing a cell identifier in a wireless communication network according to some embodiments. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, the process1200may be carried out by the base station illustrated inFIG. 3. In some examples, the process1200may be carried out by any suitable apparatus or means for carrying out the functions or algorithm described below.

At block1202, the base station (BS) may transmit unified synchronization signals within a zone associated with the base station. A UE may then utilize the unified synchronization signals to synchronize with the zone. For example, the DL traffic and control channel generation and transmission circuitry342shown and described above in reference toFIG. 3may transmit the unified synchronization signals.

At block1204, the BS may determine whether a trigger event requiring the UE to have knowledge of the cell identifier of the cell served by the BS has occurred. For example, the BS may determine whether the BS has received downlink user data traffic for transmission to the UE, whether the BS has received a system information request from the UE or whether the BS has received a random access request from the UE. For example, the PCICH trigger detection circuitry344shown and described above in reference toFIG. 3may determine whether a trigger event has occurred.

If a trigger event has occurred (Y branch of1204), at block1206, the BS may generate a Physical Cell Identification Channel (PCICH) including the cell identifier. For example, the PCICH generation circuitry345shown and described above in reference toFIG. 3may generate the PCICH.

At block1208, the base station may determine whether to transmit the PCICH to the UE within a DL-centric slot or an UL-centric slot. In some examples, the base station may determine whether the next slot to be transmitted is a DL-centric slot or an UL-centric slot and may include the PCICH within the next slot accordingly. In other examples, the base station may transmit the PCICH within only a DL-centric slot or an UL-centric slot. For example, the resource assignment and scheduling circuitry341shown and described above in reference toFIG. 3may determine whether to include the PCICH within a DL-centric slot or an UL-centric slot.

If the PCICH is to be included in a DL-centric slot (Y branch of block1208), at block1210, the base station may determine whether to include the PCICH within a DL data portion, as shown inFIG. 8, or a DL common burst, as shown inFIG. 9, of the DL-centric slot. If the base station determines to include the PCICH in the DL data portion of the DL-centric slot (Y branch of block1210), at block1212, the base station schedules resources within the DL data portion of the DL-centric slot for the PCICH and transmits the PCICH to the UE within the DL data portion of the DL-centric slot using the scheduled resources. If the base station determines to include the PCICH in the DL common burst of the DL-centric slot (N branch of block1210), at block1214, the base station schedules resources within the DL common burst of the DL-centric slot for the PCICH and transmits the PCICH to the UE within the DL common burst of the DL-centric slot using the scheduled resources. For example, the resource assignment and scheduling circuitry341and DL traffic and control channel generation and transmission circuitry342shown and described above in reference toFIG. 3may determine whether to include the PCICH in the DL data portion or DL common burst of the DL-centric slot, schedule resources accordingly, and transmit the PCICH over the scheduled resources.

If the PCICH is to be included in an UL-centric slot (N branch of block1208), at block1216, the base station schedules resources within a DL common burst of the UL-centric slot for the PCICH and transmits the PCICH to the UE within the DL common burst of the UL-centric slot using the scheduled resources. For example, the resource assignment and scheduling circuitry341and DL traffic and control channel generation and transmission circuitry342shown and described above in reference toFIG. 3may schedule resources within the DL common burst of the UL-centric slot, and transmit the PCICH over the scheduled resources.

At block1218, the base station determines whether to repeat transmission of the PCICH to the UE within an additional symbol of the same slot or within an additional slot. If the PCICH is to be repeated (Y branch of block1218), the process returns to block1206, where the base station generates the PCICH for transmission to the UE. For example, the PCICH generation circuitry345shown and described above in reference toFIG. 3may determine whether to repeat transmission of the PCICH.

FIG. 13is a flow chart illustrating an exemplary process1300for providing a cell identifier in a wireless communication network according to some embodiments. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, the process1300may be carried out by the base station illustrated inFIG. 3. In some examples, the process1300may be carried out by any suitable apparatus or means for carrying out the functions or algorithm described below.

At block1302, the base station (BS) may transmit unified synchronization signals within a zone associated with the base station. A UE may then utilize the unified synchronization signals to synchronize with the zone. For example, the DL traffic and control channel generation and transmission circuitry342shown and described above in reference toFIG. 3may transmit the unified synchronization signals.

At block1304, the BS may determine whether a trigger event requiring the UE to have knowledge of the cell identifier of the cell served by the BS has occurred. For example, the BS may determine whether the BS has received downlink user data traffic for transmission to the UE, whether the BS has received a system information request from the UE or whether the BS has received a random access request from the UE. For example, the PCICH trigger detection circuitry344shown and described above in reference toFIG. 3may determine whether a trigger event has occurred.

If a trigger event has occurred (Y branch of1304), at block1306, the BS may generate a Physical Cell Identification Channel (PCICH) including the cell identifier. For example, the PCICH generation circuitry345shown and described above in reference toFIG. 3may generate the PCICH.

At block1308, the base station may identify a subset of a plurality of sub-bands for transmission of the PCICH to the UE. For example, the downlink bandwidth may be divided into a plurality of sub-bands, where each sub-band includes a set of contiguous time-frequency resources. In some examples, a UE may have access to only part of the system downlink bandwidth due to hardware constraints and/or power savings requirements of the UE. In this example, the base station may identify the subset of the plurality of sub-bands that the UE has access to. For example, the resource assignment and scheduling circuitry341shown and described above in reference toFIG. 3may identify the subset of sub-bands for transmission of the PCICH to the UE.

At block1310, the base station may generate and transmit a signaling message indicating the subset of sub-bands including the PCICH. In some examples, the signaling message includes a master information block (MIB) transmitted over a unified physical broadcast channel (PBCH). For example, the resource assignment and scheduling circuitry341and DL traffic and control channel generation and transmission circuitry342shown and described above in reference toFIG. 3may transmit the signaling message to the UE. At block1312, the base station may then transmit the PCICH to the UE. For example, the DL traffic and control channel generation and transmission circuitry342shown and described above in reference toFIG. 3may transmit the PCICH to the UE.

FIG. 14is a flow chart illustrating an exemplary process1400for providing a cell identifier in a wireless communication network according to some embodiments. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, the process1400may be carried out by the base station illustrated inFIG. 3. In some examples, the process1400may be carried out by any suitable apparatus or means for carrying out the functions or algorithm described below.

At block1402, the base station (BS) may transmit unified synchronization signals within a zone associated with the base station. A UE may then utilize the unified synchronization signals to synchronize with the zone. For example, the DL traffic and control channel generation and transmission circuitry342shown and described above in reference toFIG. 3may transmit the unified synchronization signals.

At block1404, the BS may determine whether a trigger event requiring the UE to have knowledge of the cell identifier of the cell served by the BS has occurred. For example, the BS may determine whether the BS has received downlink user data traffic for transmission to the UE, whether the BS has received a system information request from the UE or whether the BS has received a random access request from the UE. For example, the PCICH trigger detection circuitry344shown and described above in reference toFIG. 3may determine whether a trigger event has occurred.

If a trigger event has occurred (Y branch of1404), at block1406, the BS may generate a Physical Cell Identification Channel (PCICH) including the cell identifier. For example, the PCICH generation circuitry345shown and described above in reference toFIG. 3may generate the PCICH.

At block1408, the base station may add a cyclic redundancy check (CRC) code to a payload of the PCICH, and at block1410, the base station may encode the payload of the PCICH to produce an encoded payload. For example, the DL traffic and control channel generation and transmission circuitry342shown and described above in reference toFIG. 3may add the CRC code to the PCICH payload and encode the PCICH payload to produce the encoded payload. At block1412, the base station may then transmit the PCICH including the encoded payload to the UE. For example, the DL traffic and control channel generation and transmission circuitry342shown and described above in reference toFIG. 3may transmit the PCICH to the UE.

FIG. 15is a flow chart illustrating an exemplary process1500for receiving a cell identifier in a wireless communication network according to some embodiments. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, the process1500may be carried out by the user equipment illustrated inFIG. 4. In some examples, the process1500may be carried out by any suitable apparatus or means for carrying out the functions or algorithm described below.

At block1502, the user equipment (UE) may receive unified synchronization signals within a zone associated with a serving base station (BS). At block1504, the UE may then utilize the unified synchronization signals to synchronize with the zone. For example, the DL traffic and control channel reception and processing circuitry444shown and described above in reference toFIG. 4may receive the unified synchronization signals and synchronize with the zone.

At block1506, the UE may determine whether the UE has received a Physical Cell Identification Channel (PCICH) including the cell identifier of the serving cell. For example, the PCICH may be received in response to the BS detecting the presence of downlink user data traffic for transmission to the UE, the UE transmitting a system information request to the BS or the UE transmitting a random access request to the BS. For example, the PCICH reception and processing circuitry443shown and described above in reference toFIG. 4may determine whether the PCICH has been received.

If the PCICH was received (Y branch of1506), at block1508, the UE may utilize the cell identifier within the PCICH to communicate with the serving cell (e.g., serving BS). For example, the UE may utilize the cell identifier to demodulate signals (e.g., PDCCH and/or PDSCH) received from the BS. For example, the PCICH reception and processing circuitry443shown and described above in reference toFIG. 4may process the PCICH to obtain the cell identifier and provide the cell identifier to the DL traffic and control channel reception and processing circuitry444shown and described above in reference toFIG. 4to process signals received from the BS.