Patent Description:
Wireless communication systems are rapidly growing in usage. Further, wireless communication technology has evolved from voice-only communications to also include the transmission of data, such as Internet and multimedia content, to a variety of devices.

<CIT> discloses a technique for an enhanced transmission time interval, TTI, bundling design. A BS determines resources for a new physical broadcast channel (PBCH) and communicate with a user equipment (UE) based on the new PBCH. The new PBCH may be a machine type communications (MTC) PBCH and refers to a PBCH with extended coverage relative to a legacy PBCH. As illustrated in <FIG>, an MTC subframe with dense MTC_PBCH comprises a PBCH and a bundled MTC_PBCH.

<CIT> discloses a method for configuring a carrier accessible by both legacy user equipment and new user equipment. More particularly, a BS transmits a radio frame including a legacy PBCH and a new PBCH to a UE. The BS allocates a PBCH in a legacy form including a MIB in a legacy format to corresponding legacy resource elements in the radio frame and allocates a new PBCH to new resource elements (for example, first to fourth OFDM symbols of the rear slot of the fifth subframe) in the radio frame. A resource element mapper at the BS respectively allocates the legacy PBCH and the new PBCH to corresponding resource elements under the control of a processor of the BS.

<CIT> a method in which a BS generates an EPBCH using a frequency division multiplexed (FDM) structure, wherein the EPBCH spans a subframe duration. EPBCH resource blocks (RBs) may have a similar number of REs as legacy PBCH. If the payload size of EPBCH is different from PBCH (e.g., greater than <NUM> bits), the number of RBs may be revised accordingly. Or the EPBCH payload size may be different from the PBCH payload size. EPBCH may use more than <NUM> RBs and a longer TTI to ensure good coverage of PBCH if the payload size is larger than <NUM> bits. The BS may generate at least a portion of the EPBCH in a manner that allows the EPBCH to be distinguished from a legacy PBCH, e.g. by scrambling it in a manner that is different than a CRC of a legacy PBCH.

<CIT> discloses a method for physical broadcast channel (PBCH) enhancement which includes receiving system information at a wireless transmit/receive unit, WTRU, on an enhanced PBCH (ePBCH) from a BS. The ePBCH is located in a set of radio frames which is a subset of available radio frames, where the subset includes fewer than all the available radio frames. The ePBCH is received in at least one radio frame of the set of radio frames. PBCH may be used in addition to ePBCH, in particular, it may be combined with ePBCH. The ePBCH time window may be <NUM>, which may be double the legacy PBCH time window. The method is particularly advantageous for low cost machine-type-communication (LC-MTC) WTRUs.

<CIT> discloses a method for transmitting a new PBCH in order to enhance the coverage for low-cost UEs (MTC UEs). The new PBCH may be transmitted with different SFN value than the SFN in PBCH in one super frame.

In general, in an aspect, a method for operating a base station (BS) includes generating an extended physical broadcast channel (EPBCH) transmission including one or more legacy PBCH blocks and one or more EPBCH blocks within an extension window. A size of the extension window is determined based at least in part on a PBCH repetition number and a number of the legacy PBCH blocks relative to a number of the EPBCH blocks. The EPBCH transmission is transmitted, by the BS, to one or more user equipment (UE).

In general, in an aspect, a BS includes one or more processors and memory that, when executed by the one or more processors, cause the one or more processors to perform operations including: generating an EPBCH transmission including one or more legacy PBCH blocks and one or more EPBCH blocks within an extension window, where a size of the extension window is determined based at least in part on a PBCH repetition number and a number of the legacy PBCH blocks relative to a number of the EPBCH blocks, and transmitting, by the BS, the EPBCH transmission to one or more UEs.

In general, in an aspect, non-transitory computer readable storage medium stores instructions that, when executed by one or more processors, cause the one or more processors to perform operations including: generating an EPBCH transmission including one or more legacy PBCH blocks and one or more EPBCH blocks within an extension window, where a size of the extension window is determined based at least in part on a PBCH repetition number and a number of the legacy PBCH blocks relative to a number of the EPBCH blocks, and transmitting, by a BS, the EPBCH transmission to one or more UE.

Implementations of any of the above aspects can include one or a combination of two or more of the following features.

The one or more EPBCH blocks can transmitted by the BS in each transmission time interval (TTI). In some implementations, the BS can determine whether an EPBCH block of the one or more EPBCH blocks overlaps with another data block in a current TTI, and the transmission of the EPBCH block can be scheduled based on the determination. In some implementations, the one or more EPBCH blocks are transmitted by the BS at a predefined periodicity according to a time-domain pattern. For example, the EPBCH blocks can be transmitted according to a time-domain pattern defined by SFN mod (m*T), where SFN represents system frame number, T represents a PBCH block period, and m represents a number of PBCH periods. The predefined periodicity can be based at least in part on a frequency band of the EPBCH transmission.

In some implementations, the extension window starts from a slot after the last of the one or more legacy PBCH blocks. Alternatively, in some implementations, the extension window starts from a slot before the first of the one or more legacy PBCH blocks and ends at a slot after the last of the one or more legacy PBCH blocks. At least one of the one or more EPBCH blocks can include PBCH. The PBCH can be scaled and mapped to two symbols. The PBCH can occupy an increased number of resource blocks in each of the two symbols relative to a number of resource blocks occupied by PBCH in each symbol of the legacy PBCH blocks. In some implementations, the symbols of the one or more EPBCH blocks are mapped to preserve uplink control symbols or downlink control symbols or both. In some implementations, the one or more EPBCH blocks include a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) in addition to the PBCH.

In general, in an aspect, a method for operating UE includes receiving, from a BS, an EPBCH transmission comprising one or more legacy PBCH blocks and one or more EPBCH blocks included in an extension window. A size of the extension window is determined based at least in part on a PBCH repetition number and a number of the legacy PBCH blocks relative to a number of the EPBCH blocks The EPBCH transmission is processed by the UE to obtain system information.

In general, in an aspect, a UE includes one or more processors and memory storing instructions that, when executed by the one or more processors, cause the one or more processors to perform operations including receiving, from a BS, an EPBCH transmission including one or more legacy PBCH blocks and one or more EPBCH blocks included in an extension window, where a size of the extension window is determined based at least in part on a PBCH repetition number and a number of the legacy PBCH blocks relative to a number of the EPBCH blocks, and processing the EPBCH transmission to obtain system information.

In general, in an aspect, a non-transitory computer readable storage medium storing instructions that, when executed by one or more processors, cause the one or more processors to perform operations including receiving, from a BS, an EPBCH transmission including one or more legacy PBCH blocks and one or more EPBCH blocks included in an extension window, where a size of the extension window is determined based at least in part on a PBCH repetition number and a number of the legacy PBCH blocks relative to a number of the EPBCH blocks, and processing the EPBCH transmission to obtain system information.

The one or more EPBCH blocks can be received by the UE in each transmission time interval (TTI). In some implementations, the BS is configured to determine whether an EPBCH block of the one or more EPBCH blocks overlaps with another data block in a current TTI, and the EPBCH block is received based on a determination by the BS that the EPBCH block does not overlap with another data block in the current TTI. In some implementations, the one or more EPBCH blocks are received by the UE at a predefined periodicity according to a time-domain pattern. For example, the EPBCH blocks can be received according to a time-domain pattern defined by SFN mod (m*T), where SFN represents system frame number, T represents a PBCH block period, and m represents a number of PBCH periods. The predefined periodicity can be based at least in part on a frequency band of the EPBCH transmission.

The UE can be a reduced capability UE having one or a combination of two or more of the following features: a reduced bandwidth, a reduced peak data rate, a reduced transmission power, a reduced number of soft channel bits, a reduced transport block size for broadcast or unicast, or no simultaneous reception of broadcast or unicast transport blocks.

In some implementations, the extension window starts from a slot after the last of the one or more legacy PBCH blocks. Alternatively, in some implementations, the extension window starts from a slot before the first of the one or more legacy PBCH blocks and ends at a slot after the last of the one or more legacy PBCH blocks. The UE can determine whether an EPBCH block of the one or more EPBCH blocks is present in the transmission by correlating hypothetical resource elements containing EPBCH with the received EPBCH transmission. At least one of the one or more EPBCH blocks can include PBCH. The PBCH can be scaled and mapped to two symbols. The PBCH can occupy an increased number of resource blocks in each of the two symbols relative to a number of resource blocks occupied by PBCH in each symbol of the legacy PBCH blocks. In some implementations, the symbols of the one or more EPBCH blocks are mapped to preserve uplink control symbols or downlink control symbols or both. In some implementations, the one or more EPBCH blocks include a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) in addition to the PBCH.

Embodiments of the invention are those described below with reference to <FIG>. The techniques described here relate to an extended physical broadcast channel (EPBCH) which can improve coverage for user equipment (UE), including reduced capability UE, in wireless communication networks such as a <NUM> new radio (NR) network. In some implementations, the EBPCH includes repeated transmissions of PBCH information during an extension window that starts before or after a legacy PBCH transmission. In this manner, UEs are provided with more opportunities and greater flexibility to obtain system information to connect to the wireless communication network. The EPBCH may be transmitted during each transmission time interval (TTI), or may be dynamically transmitted based on the presence of overlapping transmissions or according to a time-domain pattern to avoid collisions and reduce power consumption. The techniques described here also provide for mapping of the EPBCH transmission to resources within the channel in a way that conforms with existing standards.

<FIG> illustrates an example wireless communication system <NUM>.

The system <NUM> includes a base station 102A which communicates over a transmission medium with one or more user devices 106A, 106B,. In some implementations, the UEs may be reduced capability or "light" UEs, as described in detail below.

The communication area (or coverage area) of the base station may be referred to as a "cell. " The base station 102A and the UEs <NUM> may be configured to communicate over the transmission medium using any of various radio access technologies (RATs), also referred to as wireless communication technologies, or telecommunication standards, such as GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-Advanced (LTE-A), <NUM> new radio (<NUM> NR), HSPA, or 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), or combinations of them, among others. Note that if the base station 102A is implemented in the context of LTE, it may alternately be referred to as an 'eNodeB' or `eNB. ' Note that if the base station 102A is implemented in the context of <NUM> NR, it may alternately be referred to as 'gNodeB' or 'gNB.

The base station 102A is equipped to communicate with a network <NUM> (e.g., a core network of a cellular service provider, a telecommunication network such as a public switched telephone network (PSTN), or the Internet, or combinations of them, among others). Thus, the base station 102A may facilitate communication between the user devices and between the user devices and the network <NUM>. In particular, the cellular base station 102A may provide UEs <NUM> with various telecommunication capabilities, such as voice, SMS and data services.

The base station 102A and other similar base stations (such as base stations 102B. 102N) operating according to the same or a different cellular communication standard may comprise a network of cells, which may provide continuous or nearly continuous overlapping service to UEs 106A-N and similar devices over a geographic area in accordance with, for example, one or more cellular communication standards.

Thus, while the base station 102A may act as a "serving cell" for the UEs 106AN as illustrated in <FIG>, each UE <NUM> may also be capable of receiving signals from (and possibly within communication range of) one or more other cells (which might be provided by base stations 102B-N or any other base stations, or by UEs themselves), which may be referred to as "neighboring cells. " Such cells may also be capable of facilitating communication between user devices and/or between user devices and the network <NUM>. For example, the base stations 102A-B illustrated in <FIG> might be macro cells, while the base station 102N might be a micro cell.

In some embodiments, the base station 102A may be a next generation base station, e.g., a <NUM> New Radio (<NUM> NR) base station, or "gNB. " In some embodiments, a gNB may be connected to a legacy evolved packet core (EPC) network or to a NR core (NRC) network, among others. In addition, a gNB cell may include one or more transition and reception points (TRPs).

Note that a UE <NUM> may be capable of communicating using multiple wireless communication standards. For example, the UE <NUM> may be configured to communicate using a wireless networking (e.g., Wi-Fi) or peer-to-peer wireless communication protocol (e.g., Bluetooth or Wi-Fi peer-to-peer), or both, in addition to at least one cellular communication protocol (e.g., GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-A, <NUM> NR, HSPA, or 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), or combinations of them, among others). The UE <NUM> may also (or alternatively) be configured to communicate using one or more global navigational satellite systems (GNSS), such as GPS or GLONASS, one or more mobile television broadcasting standards (e.g., ATSC-M/H or DVB-H), and/or any other wireless communication protocol, if desired. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

<FIG> illustrates user equipment <NUM> (e.g., one of the devices 106A through 106N) in communication with a base station <NUM>. The UE <NUM> may be a device with cellular communication capability such as a mobile phone, a hand-held device, a computer or a tablet, or virtually any type of wireless device, including wireless sensors, surveillance equipment, or wearables devices, among others. In some implementations, the UE <NUM> is a reduced capability or "light" UE, as described below.

The UE <NUM> may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some embodiments, the UE <NUM> may be configured to communicate using, for example, CDMA2000 (1xRTT/1xEV-DO/HRPD/eHRPD) or LTE using a single shared radio and/or GSM or LTE using the single shared radio. The shared radio may couple to a single antenna, or may couple to multiple antennas (e.g., for MIMO) for performing wireless communications. In general, a radio may include any combination of a baseband processor, analog RF signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc.), or digital processing circuitry (e.g., for digital modulation as well as other digital processing). Similarly, the radio may implement one or more receive and transmit chains using the aforementioned hardware. For example, the UE <NUM> may share one or more parts of a receive or transmit chain, or both, between multiple wireless communication technologies, such as those discussed above.

In some implementations, the UE <NUM> includes separate transmit or receive chains, or both, (e.g., including separate antennas and other radio components) for each wireless communication protocol with which it is configured to communicate. In some implementations, the UE <NUM> may include one or more radios which are shared between multiple wireless communication protocols, and one or more radios which are used exclusively by a single wireless communication protocol.

<FIG> illustrates an example block diagram of a communication device <NUM>. It is noted that the block diagram of the communication device <NUM> in <FIG> is only one example of a possible communication device. In some implementations, communication device <NUM> may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet, a wireless sensor, a video surveillance system, or a wearable device, or a combination of them, among other devices. As shown, the communication device <NUM> may include a set of components <NUM> configured to perform core functions. For example, this set of components may be implemented as a system on chip (SOC), which may include portions for various purposes. Alternatively, this set of components <NUM> may be implemented as separate components or groups of components for the various purposes. The set of components <NUM> may be coupled (e.g., communicatively; directly or indirectly) to various other circuits of the communication device <NUM>.

For example, the communication device <NUM> may include various types of memory (e.g., including NAND flash <NUM>), an input/output interface such as connector I/F <NUM> (e.g., for connecting to a computer system; dock; charging station; input devices, such as a microphone, camera, keyboard; output devices, such as speakers), a display <NUM>, which may be integrated with or external to the communication device <NUM>, and cellular communication circuitry <NUM> such as for <NUM> NR, LTE, GSM, among others, and short to medium range wireless communication circuitry <NUM> (e.g., Bluetooth™ and WLAN circuitry). In some embodiments, the communication device <NUM> may include wired communication circuitry (not shown), such as a network interface card, e.g., for Ethernet.

The cellular communication circuitry <NUM> may couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas <NUM> and <NUM>. The short to medium range wireless communication circuitry <NUM> may also couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas <NUM> and <NUM>. The short to medium range wireless communication circuitry <NUM> or cellular communication circuitry <NUM>, or both, may include multiple receive chains and multiple transmit chains for receiving and transmitting multiple spatial streams, such as in a multiple-input multiple output (MIMO) configuration.

In some implementations, the cellular communication circuitry <NUM> may include dedicated receive chains (including and/or coupled to, e.g., communicatively; directly or indirectly. In addition, in some implementations, the cellular communication circuitry <NUM> may include a single transmit chain that may be switched between radios dedicated to specific RATs.

The communication device <NUM> may also include or be configured for use with one or more user interface elements. The user interface elements may include any of various elements, such as the display <NUM> (which may be a touchscreen display), a keyboard (which may be a discrete keyboard or may be implemented as part of a touchscreen display), a mouse, a microphone, a speaker, one or more cameras, one or more buttons, or combinations of them, among various other elements capable of providing information to a user or receiving or interpreting user input.

As shown, the SOC <NUM> may include processor(s) <NUM>, which may execute program instructions for the communication device <NUM> and display circuitry <NUM>, which may perform graphics processing and provide display signals to the display <NUM>. The processor(s) <NUM> may also be coupled to memory management unit (MMU) <NUM>, which may be configured to receive addresses from the processor(s) <NUM> and translate those addresses to locations in memory (e.g., memory <NUM>, read only memory (ROM) <NUM>, NAND flash memory <NUM>) and/or to other circuits or devices, such as the display circuitry <NUM>, short range wireless communication circuitry <NUM>, cellular communication circuitry <NUM>, connector I/F <NUM>, and/or display <NUM>. The MMU <NUM> may be configured to perform memory protection and page table translation or set up. In some implementations, the MMU <NUM> may be included as a portion of the processor(s) <NUM>.

The communication device <NUM> may include hardware and software components for implementing the above features for time division multiplexing UL data for NSA NR operations. The processor <NUM> of the communication device <NUM> may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor <NUM> may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor <NUM> of the communication device <NUM>, in conjunction with one or more of the other components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be configured to implement part or all of the features described herein.

The processor <NUM> may include one or more processing elements. For example, the processor <NUM> may include one or more integrated circuits (ICs) that are configured to perform the functions of the processor <NUM>. Each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, among other circuitry) configured to perform the functions of processor(s) <NUM>.

Further, the cellular communication circuitry <NUM> and short range wireless communication circuitry <NUM> may each include one or more processing elements. In other words, one or more processing elements may be included in cellular communication circuitry <NUM> and, similarly, one or more processing elements may be included in short range wireless communication circuitry <NUM>. Thus, cellular communication circuitry <NUM> may include one or more integrated circuits (ICs) that are configured to perform the functions of cellular communication circuitry <NUM>. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of cellular communication circuitry <NUM>. Similarly, the short range wireless communication circuitry <NUM> may include one or more ICs that are configured to perform the functions of short range wireless communication circuitry <NUM>. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of short range wireless communication circuitry <NUM>.

<FIG> illustrates an example block diagram of a base station <NUM>. It is noted that the base station of <FIG> is an example of a possible base station. As shown, the base station <NUM> includes processor(s) <NUM> which may execute program instructions for the base station <NUM>. The processor(s) <NUM> may be coupled to memory management unit (MMU) <NUM>, which may be configured to receive addresses from the processor(s) <NUM> and translate those addresses to locations in memory (e.g., memory <NUM> and read only memory (ROM) <NUM>) or to other circuits or devices.

The network port <NUM> may be configured to couple to a telephone network and provide a plurality of devices, such as UE devices <NUM>, access to the telephone network as described above with reference to <FIG>.

The core network may provide mobility related services or other services to a plurality of devices, such as UE devices <NUM>. In some implementations, the network port <NUM> couples a telephone network using the core network, or the core network may provide a telephone network (e.g., among other UE devices serviced by the cellular service provider).

In some implementations, the base station <NUM> is a next generation base station, e.g., a <NUM> New Radio (5GNR) base station, or "gNB".

The radio <NUM> may be configured to communicate via various wireless communication standards, including, but not limited to, <NUM> NR, LTE, LTE-A, GSM, UMTS, CDMA2000, or Wi-Fi, or combinations of them, among others.

As another possibility, the base station <NUM> may include a multi-mode radio which is capable of performing communications according to any of multiple wireless communication technologies (e.g., <NUM> NR and Wi-Fi, LTE and Wi-Fi, LTE and UMTS, LTE and CDMA2000, UMTS and GSM, or combinations of them, among others).

The BS <NUM> may include hardware and software components for implementing or supporting implementation of features described herein.

In some implementations, the processor(s) <NUM> are comprised of one or more processing elements. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, among other circuitry) configured to perform the functions of the processor(s) <NUM>.

In some implementations, the radio <NUM> is comprised of one or more processing elements.

<FIG> illustrates an example block diagram of cellular communication circuitry <NUM>. It is noted that the block diagram of the cellular communication circuitry <NUM> of <FIG> is an example of a possible cellular communication circuit. In some implementations, the cellular communication circuitry <NUM> may be included in a communication device, such as the communication device <NUM> described above. As noted above, communication device <NUM> may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet, a wireless sensor, surveillance equipment, or wearables devices, or a combination of them, among other devices.

The cellular communication circuitry <NUM> may couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas <NUM> a-b and <NUM> as shown (in <FIG>). In some implementations, the cellular communication circuitry <NUM> includes or is communicatively coupled to dedicated receive chains, processors, or radios for multiple RATs (e.g., a first receive chain for LTE and a second receive chain for <NUM> NR). For example, as shown in <FIG>, cellular communication circuitry <NUM> may include a modem <NUM> and a modem <NUM>. Modem <NUM> may be configured for communications according to a first RAT, e.g., such as LTE or LTE-A, and modem <NUM> may be configured for communications according to a second RAT, e.g., such as 5GNR.

The modem <NUM> includes one or more processors <NUM> and a memory <NUM> in communication with the processors <NUM>. The modem <NUM> is in communication with a radio frequency (RF) front end <NUM>. The RF front end <NUM> may include circuitry for transmitting and receiving radio signals. For example, the RF front end <NUM> includes receive circuitry (RX) <NUM> and transmit circuitry (TX) <NUM>. In some implementations, the receive circuitry <NUM> is in communication with downlink (DL) front end <NUM>, which may include circuitry for receiving radio signals via antenna 335a.

Similarly, the modem <NUM> includes one or more processors <NUM> and a memory <NUM> in communication with the processors <NUM>. The modem <NUM> is in communication with an RF front end <NUM>. The RF front end <NUM> may include circuitry for transmitting and receiving radio signals. For example, the RF front end <NUM> may include receive circuitry <NUM> and transmit circuitry <NUM>. In some implementations, the receive circuitry <NUM> is in communication with DL front end <NUM>, which may include circuitry for receiving radio signals via antenna 335b.

The modem <NUM> may include hardware and software components for implementing the above features or for time division multiplexing UL data for NSA NR operations, as well as the various other techniques described herein. The processors <NUM> may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), the processor <NUM> may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor <NUM>, in conjunction with one or more of the other components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> may be configured to implement some or all of the features described herein.

The processors <NUM> may include one or more processing elements.

The modem <NUM> may include hardware and software components for implementing the above features for time division multiplexing UL data for NSA NR operations, as well as the various other techniques described herein. The processors <NUM> may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor <NUM> may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor <NUM>, in conjunction with one or more of the other components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> may be configured to implement part or all of the features described herein.

In addition, the processors <NUM> may include one or more processing elements. Thus, the processors <NUM> may include one or more integrated circuits (ICs) that are configured to perform the functions of processors <NUM>.

According to certain aspects of the present disclosure, a new category of reduced capability <NUM> NR UE (sometimes referred to here as a "NR light UE" or "NL UE") is introduced. The NR light UE can include some or all of the components of a typical UE (e.g., the UE <NUM>, described above), but can include certain hardware and software modifications or reductions, such as a reduced number of RX or TX antennas, to reduce cost or complexity, or both. For example, in some implementations, the NR light UE includes one or a combination of two or more of the following relaxed requirements to reduce UE complexity: no simultaneous receptions of multiple unicast or broadcast transport blocks (TBs), or both; a reduced TB size for broadcast and unicast data; a reduced number of soft channel bits; operating in a reduced bandwidth system at RF/Base Band (BB) for downlink (DL) and uplink (UE) with possible retuning within the whole NR system bandwidth (e.g., the reduced bandwidth can depend on the configured subcarrier spacing); a reduced transmission power, such as a maximum transmission power; or a reduced UL or DL data rate, such as a peak data rate. By establishing the NR light UE category within the <NUM> NR framework, UE cost and complexity can be reduced, and wireless communication support can be provided for additional UEs, such as industrial sensors, video surveillance systems, and wearable devices, which meet the relaxed capability requirements.

Other features of the NR UE can include the following. In some implementations, the NL UE accesses a cell (e.g., the base station <NUM>) only if the master information block (MIB) received from the cell indicates permission. Otherwise, the NL UE can consider the cell as barred. In some implementations, aspects for common control and random access include: a NL UE may receive separate occurrence of system information block (SIB) from the base station (e.g. in different time or frequency resources), broadcast control channel (BCCH) modification period for NL UEs may be a multiple of the legacy (e.g., non-NL UE) BCCH modification period, a set of physical random access channel (PRACH) resources, such as frequency, time, preamble or random access response (RAR) related information, or combinations of them, may be provided separately to the NL UEs.

For NL UEs, reducing, for example, the number of RX antennas can reduce cost, but would turn in reduced coverage for this type of UE. Thus, the coverage loss should be addressed for different DL channels to maintain coverage performance of NL UEs.

The techniques described here compensate coverage loss for NL UEs and other UEs through PBCH extension. In this manner, a cell can provide NL UEs (and other UEs) more opportunities and greater flexibility to obtain system information to connect to the cell and therefore maintain wireless communication coverage. Although these techniques are described in the context of PBCH channel, the techniques can be applied to other DL channels, such as the physical downlink control channel (PDCCH), in some implementations. Further, although these techniques are described in the context of NL UEs, the techniques are generally applicable to other UEs such as those described here. For purposes of the present disclosure, the term "legacy PBCH" is used to refer generally to PBCH transmitted in accordance with a previous version of a standard (e.g., <NUM> NR release <NUM> or earlier) relative to the extended PBCH described here.

In general, PBCH, both legacy and extended, provides basic system information to UEs, including NL UEs. A cell (e.g., the base station <NUM>) can transmit the PBCH in a downlink transmission to a UE. The UE can decode the information on the PBCH in order to access the cell. Information provided by the PBCH can include, for example, timing information within radio frame, SS burst set periodicity, system frame number, and other higher layer information. In some implementations, other broadcast information, such as a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), are transmitted with the PBCH.

In some implementations, PBCH may be repeatedly extended within a transmission time interval (TTI), which may be <NUM> in the case of <NUM> NR PBCH. Different options can be considered for extended PBCH (EPBCH) transmission across TTIs. In some implementations, the base station can transmit the EPBCH in every TTI (e.g., every <NUM> cycle) as long as extended transmission is enabled (e.g., based on higher layer signaling such as PBCH/System Information Blocks (SIB)). This is beneficial from a power saving perspective, as a UE can assume the same hypothesis regarding presence of an EPBCH block upon waking up, for example, in discontinuous reception (DRX) operation, as it had determined during an earlier acquisition period. In this and other approaches, the legacy PBCH may be transmitted in its normal location to ensure compatibility with UEs that do not use the EPBCH approach. Moreover, the legacy PBCH can be utilized by, for example, the NL UE in addition to or instead of the EPBCH.

In some implementations, EPBCH transmission is dynamically determined by a cell during each TTI, as illustrated in <FIG>. This provides flexibility for a network scheduler of the cell to prioritize another broadcast transmission, such as a paging transmission, that may be overlapped with EPBCH transmissions. For example, if the network scheduler determines that another transmission is scheduled for transmission such that the transmission would overlap with an EPBCH transmission, the network scheduler can give the other transmission higher priority and can withhold or delay the EPBCH transmission (e.g., until the next TTI), as shown in <FIG>. Under this approach, it is up to the UE to detect the presence of an EPBCH transmissions during each TTI. In some implementations, a UE correlates hypothetical resource elements (REs) containing EPBCH transmissions to determine whether an actual EPBCH exists in the current TTI. To reduce power consumption, a UE may power off or early-terminate EPBCH detection in the remainder of the frame if it determines an absence of EPBCH transmission in a particular cycle.

In some implementations, EPBCH transmission is operated at a predefined periodicity according to one or more time-domain patterns. This option is mainly motivated by the potential power saving benefit due to, for example, its predictability and minimizing signaling overhead by avoiding unnecessary PBCH repetition. In some implementations, the EPBCH transmission period boundaries are defined by system frame number (SFN) values according to the equation SFN mod (m * T) = <NUM>, where m is the number of EPBCH blocks per legacy PBCH/Synchronization signal block (SSB) period, and T is the legacy PBCH/SSB block period. The value of m can be determined based on, for example, the frequency bands. In some implementations, the value of m is fixed in a specification (e.g., one or more of the 3GPP <NUM> NR technical specifications). An example of this approach is shown in <FIG> with m = <NUM>.

In some implementations, one or more of these approaches are combined. For example, the approaches described with reference to <FIG> and <FIG> may be combined by predefining a pair of values {m, n}, where m is as described above and n is the number of EPBCH transmissions with the EBPCH period. An example of this combined approach is illustrated in <FIG> with {m=<NUM>, n=<NUM>}.

To facilitate EPBCH transmission within the existing standards, an extension window can be defined and the EPBCH transmission can be confined to the extension window. Referring to <FIG>, in some implementations, a EPBCH extension window <NUM> starts from a slot after the last slot of the legacy SS/PBCH block <NUM> (e.g., after the reception symbol). Referring to <FIG>, to further reduce UE initial access latency, an EPBCH extension window <NUM> can be located both before the first slot of the legacy SS/PBCH block <NUM> and after the last slot of the legacy SS/PBCH block.

Referring to <FIG>, in some implementations, the size of the EPBCH extension window size W is determined by <MAT>, where R is the PBCH repetition number, L is the number of legacy SSB blocks (sometimes referred to here as SS/PBCH blocks or simply PBCH blocks), and M is the number of EPBCH candidates within a slot or bundled <NUM>-slots (e.g., for <NUM> sub-carrier spacing (SCS)). This equation can be used to define the EPBCH extension window size regardless of whether the EBPCH starts before or after the legacy PBCH block. In some implementations, a slot offset value (O) is used to determine the first slot of the EPBCH transmission. The offset value can depend on, for example, the SCS used for the EPBCH transmission, where O is <NUM> or <NUM> for <NUM> or <NUM> SCS, <NUM> for <NUM> SCS, and <NUM> for <NUM> SCS.

As shown in <FIG>, in some implementations, an EPBCH <NUM> includes PBCH <NUM>, PSS <NUM>, and SSS <NUM>. Including this additional signaling information in the EPBCH can reduce access latency by a UE. In some implementations, an EPBCH <NUM> includes PBCH <NUM> without PSS or SSS to minimize signaling overhead. Under this approach, the sequence of complex-value PBCH symbols (e.g., PBCH <NUM>) can be scaled by a factor βEPBCH to produce PBCH symbols (e.g., PBCH <NUM>) that conform to power allocation and boosting requirements. The PBCH symbols <NUM> can then be mapped, for example, in sequence to resource elements in two consecutive symbols i and i+<NUM>. In some implementations, the EPBCH <NUM> may occupy different bandwidth or number of resource blocks (RBs) compared to legacy PBCH (e.g., PBCH <NUM>). For example, as shown in <FIG>, the EPBCH <NUM> may transmit over increased number of RBs (e.g., <NUM> PRBs) in each of two consecutive symbols to reach a same coding rate as a legacy <NUM>-symbol PBCH using <NUM> PRBs.

The techniques described here also provide for mapping of the EPBCH transmission to resources within the channel, as shown in <FIG>. In some implementations, EPBCH symbols are mapped to preserve X symbols at the beginning of a slot, for example, for DL control data. For example, the EPBCH can be mapped to preserve X = <NUM> for <NUM> or <NUM> SCS, or X = <NUM> for <NUM> SCS. In some implementations, EPBCH symbols can be mapped to preserve Y symbols at the end of a slot, for example, for guard period and UL control data. For example, the EPBCH can be mapped to preserve Y = <NUM> for <NUM>, <NUM>, or <NUM> SCS. In some implementations, such as for larger SCS (e.g., <NUM>), X and Y symbols may be reserved for every two concatenated consecutive slots (e.g., X = <NUM> and Y = <NUM>). The EPBCH transmission may or may not cross the middle of the slot defined by, for example, <NUM> SCS, as shown by pattern <NUM> and pattern <NUM> in <FIG>, respectively. Other patterns can be used, for example, based at least in part on the SCS for the EPBCH transmission.

The EPBCH candidates in an extension window can be indexed in an order, such as an ascending order in the time domain. For example, the EBPCH candidates can be indexed from <NUM> to (R*L)-<NUM>, where R is the PBCH repetition number and L is the number of legacy SSB blocks. In some implementations, the association between the PBCH in a legacy SSB block i and EPBCH index j is computed as follows: j = i + L * n, <NUM> ≤ n ≤ R. <FIG> illustrate different examples of one-to-one mapping or association between SSB blocks and EPBCH candidates assuming a <NUM> SSC and L = <NUM> and R = <NUM>. In particular, <FIG> illustrates an example of mapping or association for an EPBCH extension window occurring after the SSB blocks, and <FIG> illustrates an example of mapping or associate where the EPBCH extension window starts before and spans the SSB blocks. In some implementations, a different redundancy version (RV) of the master information block (MIB) may be used for EPBCH transmissions. For example, the RV sequence (e.g., {<NUM>,<NUM>,<NUM>,<NUM>}) may be predefined in a standard, such the <NUM> NR standard.

<FIG> illustrates a flowchart of an example process <NUM> for PBCH extension. In some implementations, the process <NUM> is performed by one or more of the devices or systems described here.

Operations of the process <NUM> include generating an extended physical broadcast channel (EPBCH) transmission including one or more legacy PBCH blocks and one or more EPBCH blocks within an extension window (<NUM>). The EPBCH can be generated by, for example, the BS <NUM>. A size of the extension window (e.g., the extension window <NUM>, <NUM>) can be determined based at least in part on a PBCH repetition number and a number of the legacy PBCH blocks relative to a number of the EPBCH blocks.

In some implementations, the one or more EPBCH blocks are transmitted by the BS in each transmission time interval (TTI) (e.g., <NUM>). In some implementations, the BS can determine whether an EPBCH block of the one or more EPBCH blocks overlaps with another data block in a current TTI, and the transmission of the EPBCH block can be scheduled based on the determination. In some implementations, the one or more EPBCH blocks are transmitted by the BS at a predefined periodicity according to a time-domain pattern. For example, the EPBCH blocks can be transmitted according to a time-domain pattern defined by SFN mod (m*T), where SFN represents system frame number, T represents a PBCH block period, and m represents a number of PBCH periods. The predefined periodicity can be based at least in part on a frequency band of the EPBCH transmission.

In some implementations, the extension window starts from a slot after the last of the one or more legacy PBCH blocks. Alternatively, in some implementations, the extension window starts from a slot before the first of the one or more legacy PBCH blocks and ends at a slot after the last of the one or more legacy PBCH blocks.

The EPBCH transmission is transmitted to one or more UEs (<NUM>). For example, the EPBCH transmission can be transmitted by the BS <NUM> to one or more UEs 106A, 106B,. 106N, which can include NL UEs. At least one of the one or more EPBCH blocks can include PBCH. The PBCH can be scaled and mapped to two symbols. The PBCH can occupy an increased number of resource blocks in each of the two symbols relative to a number of resource blocks occupied by PBCH in each symbol of the legacy PBCH blocks. In some implementations, the symbols of the one or more EPBCH blocks are mapped to preserve uplink control symbols or downlink control symbols or both. In some implementations, the one or more EPBCH blocks include a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) in addition to the PBCH.

<FIG> illustrates a flowchart of an example process <NUM> for PBCH extension. In some implementations, the process <NUM> is performed by one or more of the systems and devices described here.

Operations of the process <NUM> include receiving, from a BS, an extended physical broadcast channel (EPBCH) transmission including one or more legacy PBCH blocks and one or more EPBCH blocks included in an extension window (<NUM>). A size of the extension window is determined based at least in part on a PBCH repetition number and a number of the legacy PBCH blocks relative to a number of the EPBCH blocks. For example, the EPBCH transmission can be received by a UE <NUM> from the BS <NUM>. In some implementations, the UE includes a reduced capability UE (e.g., a NL UE) having one or a combination of two or more of the following features: a reduced bandwidth, a reduced peak data rate, a reduced transmission power, a reduced number of soft channel bits, a reduced transport block size for broadcast or unicast, or no simultaneous reception of broadcast or unicast transport blocks.

In some implementations, the one or more EPBCH blocks are received by the UE in each transmission time interval (TTI) (e.g., <NUM>). In some implementations, the BS is configured to determine whether an EPBCH block of the one or more EPBCH blocks overlaps with another data block in a current TTI, and the EPBCH block is received based on a determination by the BS that the EPBCH block does not overlap with another data block in the current TTI. In some implementations, the one or more EPBCH blocks are received by the UE at a predefined periodicity according to a time-domain pattern. For example, the EPBCH blocks can be received according to a time-domain pattern defined by SFN mod (m*T), where SFN represents system frame number, T represents a PBCH block period, and m represents a number of PBCH periods. The predefined periodicity can be based at least in part on a frequency band of the EPBCH transmission.

In some implementations, the extension window starts from a slot after the last of the one or more legacy PBCH blocks. Alternatively, in some implementations, the extension window starts from a slot before the first of the one or more legacy PBCH blocks and ends at a slot after the last of the one or more legacy PBCH blocks. The UE can determine whether an EPBCH block of the one or more EPBCH blocks is present in the transmission by correlating hypothetical resource elements containing EPBCH with the received EPBCH transmission.

The EPBCH transmission is processed to obtain system information (<NUM>). For example, the UE (e.g., the UE <NUM>) can process the EPBCH transmission to obtain information for connecting to the BS. For example, the EPBCH transmission can be transmitted by the BS <NUM> to one or more UEs 106A, 106B,. 106N, which can include NL UEs. At least one of the one or more EPBCH blocks can include PBCH. The PBCH can be scaled and mapped to two symbols. The PBCH can occupy an increased number of resource blocks in each of the two symbols relative to a number of resource blocks occupied by PBCH in each symbol of the legacy PBCH blocks. In some implementations, the symbols of the one or more EPBCH blocks are mapped to preserve uplink control symbols or downlink control symbols or both. In some implementations, the one or more EPBCH blocks include a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) in addition to the PBCH.

Claim 1:
A method for operating a base station, BS, (<NUM>), comprising:
generating (<NUM>) an extended physical broadcast channel, EPBCH, transmission comprising one or more legacy PBCH blocks and one or more EPBCH blocks included in an extension window, wherein a size of the extension window is determined based at least in part on a PBCH repetition number and a number of the legacy PBCH blocks relative to a number of the EPBCH blocks; and
transmitting (<NUM>), by the BS, the EPBCH transmission to one or more user equipment, UE.