Patent Publication Number: US-10326493-B2

Title: Control channel transmission and frequency error correction

Description:
CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM OF PRIORITY 
     The present application claims priority under 35 U.S.C. § 119(e) to: U.S. Provisional Patent Application Ser. No. 62/160,895 filed May 13, 2015, entitled “FREQUENCY OFFSET CORRECTION IN COVERAGE ENHANCED OPERATION;” and U.S. Provisional Patent Application Ser. No. 62/212,684 filed Sep. 1, 2015, entitled “PHYSICAL UPLINK CONTROL CHANNEL STRUCTURE FOR COVERAGE ENHANCEMENTS.” The contents of the above-identified patent documents are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present application relates generally to wireless communications and, more specifically, to transmitting from a user equipment a physical uplink control channel with repetitions and frequency retuning and to performing, at a base station or at a user equipment, frequency error correction based on a reception of a channel transmitted with repetitions. 
     BACKGROUND 
     Wireless communication has been one of the most successful innovations in modern history. Recently, the number of subscribers to wireless communication services exceeded five billion and continues to grow quickly. The demand of wireless data traffic is rapidly increasing due to the growing popularity among consumers and businesses of smart phones and other mobile data devices, such as tablets, “note pad” computers, net books, eBook readers, and machine type of devices. In order to meet the high growth in mobile data traffic and support new applications and deployments, improvements in radio interface efficiency and coverage is of paramount importance. 
     SUMMARY 
     This disclosure provides methods and apparatus to enable retuning in different narrowbands for repetitions of a physical uplink control channel transmission and to enable frequency offset correction using replicas of received data symbols or received control symbols in repetitions of a channel reception. 
     In a first embodiment, a method is provided. The method includes transmitting a data channel. The method also includes receiving repetitions of a control channel in response to the transmission of the data channel. A first number of the control channel repetitions is received in a first narrowband over a first number of subframes and a second number of the control channel repetitions is received in a second narrowband over a second number of subframes. The control channel is not received in either of a last subframe symbol of a last repetition in a first narrowband or in a first subframe symbol of the first repetition in the second narrowband. 
     In a second embodiment, a base station is provided. The base station includes a transmitter and a receiver. The transmitter is configured to transmit a data channel. The receiver configured to receive repetitions of a control channel in response to the transmission of the data channel. A first number of the control channel repetitions is received in a first narrowband over a first number of subframes and a second number of the control channel repetitions is received in a second narrowband over a second number of subframes. The control channel is not received in either of a last subframe symbol of a last repetition in the first narrowband or in a first subframe symbol of a first repetition in the second narrowband. 
     In a third embodiment, a user equipment (UE) is provided. The UE includes a receiver and a transmitter. The receiver is configured to receive a data channel. The transmitter is configured to transmit repetitions of a control channel in response to the reception of the data channel. A first number of the control channel repetitions is transmitted in a first narrowband over a first number of subframes and a second number of the control channel repetitions is transmitted in a second narrowband over a second number of subframes. The control channel is not transmitted in either of a last subframe symbol of a last repetition in the first narrowband or in a first subframe symbol of a first repetition in the second narrowband. 
     In a fourth embodiment, a method is provided. The method includes receiving a number of repetitions for a channel over a respective number of subframes and over a bandwidth that includes a number of sub-carriers (SCs). Each subframe from the number of subframes includes a number of symbols. The method also includes correlating, for multiple symbols and for multiple SCs, a reception in a SC k and in a symbol l of a first subframe for a first of the number of repetitions with a reception in a SC k and in a symbol l of a second subframe for a second of the number of repetitions. The method additionally includes adding the correlations for the multiple symbols and the multiple SCs. The method further includes estimating a frequency offset from a phase of the added correlations. The method also includes adjusting a frequency of a reception based on the frequency offset. 
     In a fifth embodiment, a device is provided. The device includes a receiver, a correlator, an adder, a frequency offset estimator, and a frequency offset adjustor. The receiver is configured to receive a number of repetitions for a channel over a respective number of subframes and over a bandwidth that includes a number of sub-carriers (SCs). Each subframe from the number of subframes includes a number of symbols. The correlator is configured to correlate, for multiple symbols and for multiple SCs, a reception in a SC k and in a symbol l of a first subframe for a first of the number of repetitions with a reception in a SC k and in a symbol l of a second subframe for a second of the number of repetitions. The adder is configured to add the correlations for the multiple symbols and the multiple SCs. The frequency offset estimator is configured to estimate a frequency offset from a phase of the added correlations. The frequency offset adjustor is configured to adjust a frequency of a reception based on the frequency offset. 
     Before undertaking the DETAILED DESCRIPTION below, it can be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term “couple” and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms “transmit,” “receive,” and “communicate,” as well as derivatives thereof, encompass both direct and indirect communication. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and/or. The phrase “associated with,” as well as derivatives thereof, means to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The term “controller” means any device, system or part thereof that controls at least one operation. Such a controller can be implemented in hardware or a combination of hardware and software and/or firmware. The functionality associated with any particular controller can be centralized or distributed, whether locally or remotely. The phrase “at least one of,” when used with a list of items, means that different combinations of one or more of the listed items can be used, and only one item in the list can be needed. For example, “at least one of: A, B, and C” includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C. 
     Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device. 
     Definitions for other certain words and phrases are provided throughout this disclosure. Those of ordinary skill in the art should understand that in many if not most instances such definitions apply to prior as well as future uses of such defined words and phrases. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: 
         FIG. 1  illustrates an example wireless communication network according to this disclosure; 
         FIG. 2  illustrates an example user equipment (UE) according to this disclosure; 
         FIG. 3  illustrates an example enhanced NodeB (eNB) according to this disclosure; 
         FIG. 4  illustrates an example UL SF structure for PUSCH transmission or PUCCH transmission according to this disclosure; 
         FIG. 5  illustrates a UE transmitter block diagram for a PUSCH in a SF according to this disclosure; 
         FIG. 6  illustrates an eNB receiver block diagram for a PUSCH in a SF according to this disclosure; 
         FIG. 7  illustrates a PUCCH structure for transmitting HARQ-ACK information or SR information in one slot of a SF according to this disclosure; 
         FIG. 8  illustrates a UE transmitter block diagram for HARQ-ACK information or SR information in a PUCCH according to this disclosure; 
         FIG. 9  illustrates an eNB receiver block diagram for HARQ-ACK information or SR information in a PUCCH according to this disclosure; 
         FIG. 10  illustrates a retuning structure for a PUCCH transmission with repetitions according to this disclosure; 
         FIG. 11  illustrates a PUCCH transmission structure where transmission a first SF symbol is suspended according to this disclosure; 
         FIG. 12  illustrates a PUCCH structure for transmitting HARQ-ACK information or SR information in one slot of a SF without multiplication by an OCC according to this disclosure; 
         FIG. 13  illustrates a UE transmitter for HARQ-ACK or SR information in a PUCCH without multiplication of HARQ-ACK or SR symbols or of RS symbols with an OCC according to this disclosure; 
         FIG. 14  illustrates an eNB receiver for HARQ-ACK or SR information in a PUCCH without multiplication of HARQ-ACK or SR symbols or of RS symbols with an OCC according to this disclosure; 
         FIG. 15  illustrates an example frequency offset estimation based on correlations across SCs of a DMRS symbol with subsequent DMRS symbols over three SFs according to this disclosure; 
         FIG. 16  illustrates an example frequency offset estimation based on correlations across SCs of both DMRS symbols and data symbols in a PUSCH transmission over two SFs according to this disclosure; 
         FIG. 17  illustrates an example receiver structure for frequency offset estimation according to this disclosure; 
         FIG. 18  illustrates an example frequency offset estimation based on correlations across SCs of both DMRS symbols and HARQ-ACK information symbols in a PUCCH transmission over one SF according to this disclosure; and 
         FIG. 19  illustrates a configuration by an eNB to a UE of a number of repetitions for a PUSCH transmission depending on whether or not the eNB corrects a frequency offset according to this disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 through 19 , discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any suitably arranged wireless communication system. 
     The following documents and standards descriptions are hereby incorporated by reference into the present disclosure as if fully set forth herein: 3GPP TS 36.211 v12.4.0, “E-UTRA, Physical channels and modulation” (REF 1); 3GPP TS 36.212 v12.3.0, “E-UTRA, Multiplexing and Channel coding” (REF 2); 3GPP TS 36.213 v12.4.0, “E-UTRA, Physical Layer Procedures” (REF 3); 3GPP TS 36.321 v12.4.0, “E-UTRA, Medium Access Control (MAC) protocol specification” (REF 4); and 3GPP TS 36.331 v12.4.0, “E-UTRA, Radio Resource Control (RRC) Protocol Specification” (REF 5). 
     This disclosure relates to transmitting a physical uplink control channel (PUCCH) with repetitions and retuning in different narrowbands from a user equipment (UE) and to performing frequency error correction based on a reception of a channel transmitted with repetitions at a base station or at a UE. A wireless communication network includes a downlink (DL) that conveys signals from transmission points, such as base stations or enhanced NodeBs (eNBs), to UEs. The wireless communication network also includes an uplink (UL) that conveys signals from UEs to reception points, such as eNBs. 
       FIG. 1  illustrates an example wireless network  100  according to this disclosure. The embodiment of the wireless network  100  shown in  FIG. 1  is for illustration only. Other embodiments of the wireless network  100  could be used without departing from the scope of this disclosure. 
     As shown in  FIG. 1 , the wireless network  100  includes an eNB  101 , an eNB  102 , and an eNB  103 . The eNB  101  communicates with the eNB  102  and the eNB  103 . The eNB  101  also communicates with at least one Internet Protocol (IP) network  130 , such as the Internet, a proprietary IP network, or other data network. 
     Depending on the network type, other well-known terms can be used instead of “NodeB” or “eNB,” such as “base station” or “access point.” For the sake of convenience, the terms “NodeB” and “eNB” are used in this patent document to refer to network infrastructure components that provide wireless access to remote terminals. Also, depending on the network type, other well-known terms can be used instead of “user equipment” or “UE,” such as “mobile station,” “subscriber station,” “remote terminal,” “wireless terminal,” or “user device.” A UE, can be fixed or mobile and can be a cellular phone, a personal computer device, and the like. For the sake of convenience, the terms “user equipment” and “UE” are used in this patent document to refer to remote wireless equipment that wirelessly accesses an eNB, whether the UE is a mobile device (such as a mobile telephone or smart-phone) or is normally considered a stationary device (such as a desktop computer or vending machine). 
     The eNB  102  provides wireless broadband access to the network  130  for a first plurality of UEs within a coverage area  120  of the eNB  102 . The first plurality of UEs includes a UE  111 , which can be located in a small business (SB); a UE  112 , which can be located in an enterprise (E); a UE  113 , which can be located in a WiFi hotspot (HS); a UE  114 , which can be located in a first residence (R); a UE  115 , which can be located in a second residence (R); and a UE  116 , which can be a mobile device (M) like a cell phone, a wireless laptop, a wireless PDA, or the like. The eNB  103  provides wireless broadband access to the network  130  for a second plurality of UEs within a coverage area  125  of the eNB  103 . The second plurality of UEs includes the UE  115  and the UE  116 . In some embodiments, one or more of the eNBs  101 - 103  can communicate with each other and with the UEs  111 - 116  using 5G, LTE, LTE-A, WiMAX, or other advanced wireless communication techniques. 
     Dotted lines show the approximate extents of the coverage areas  120  and  125 , which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with eNBs, such as the coverage areas  120  and  125 , can have other shapes, including irregular shapes, depending upon the configuration of the eNBs and variations in the radio environment associated with natural and man-made obstructions. 
     As described in more detail below, various components of the network  100 , such as the eNBs  101 - 103 , can receive PUCCH transmissions with repetitions and frequency retuning from UEs  111 - 116  and perform frequency error correction based on reception of channels transmitted with repetitions from UEs  111 - 116 . In addition, one or more of UEs  111 - 116  can perform PUCCH transmissions with repetitions for communication between one or more of eNBs  101 - 103  and perform frequency error correction based on reception of channels transmitted with repetitions from eNBs  101 - 103 . 
     Although  FIG. 1  illustrates one example of a wireless network  100 , various changes can be made to  FIG. 1 . For example, the wireless network  100  could include any number of eNBs and any number of UEs in any suitable arrangement. Also, the eNB  101  could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network  130 . Similarly, each eNB  102 - 103  could communicate directly with the network  130  and provide UEs with direct wireless broadband access to the network  130 . Further, the eNB  101 ,  102 , and/or  103  could provide access to other or additional external networks, such as external telephone networks or other types of data networks. 
       FIG. 2  illustrates an example UE  114  according to this disclosure. The embodiment of the UE  114  shown in  FIG. 2  is for illustration only, and the other UEs in  FIG. 1  could have the same or similar configuration. However, UEs come in a wide variety of configurations, and  FIG. 2  does not limit the scope of this disclosure to any particular implementation of a UE. 
     As shown in  FIG. 2 , the UE  114  includes an antenna  205 , a radio frequency (RF) transceiver  210 , transmit (TX) processing circuitry  215 , a microphone  220 , and receive (RX) processing circuitry  225 . The UE  114  also includes a speaker  230 , a processor  240 , an input/output (I/O) interface (IF)  245 , an input  250 , a display  255 , and a memory  260 . The memory  260  includes an operating system (OS) program  261  and one or more applications  262 . 
     The RF transceiver  210  receives, from the antenna  205 , an incoming RF signal transmitted by an eNB or another UE. The RF transceiver  210  down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is sent to the RX processing circuitry  225 , which generates a processed baseband signal by filtering, decoding, and/or digitizing the baseband or IF signal. The RX processing circuitry  225  transmits the processed baseband signal to the speaker  230  (such as for voice data) or to the processor  240  for further processing (such as for web browsing data). 
     The TX processing circuitry  215  receives analog or digital voice data from the microphone  220  or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the processor  240 . The TX processing circuitry  215  encodes, multiplexes, and/or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver  210  receives the outgoing processed baseband or IF signal from the TX processing circuitry  215  and up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna  205 . 
     The processor  240  can include one or more processors or other processing devices and can execute the OS program  261  stored in the memory  260  in order to control the overall operation of the UE  114 . For example, the processor  240  could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver  210 , the RX processing circuitry  225 , and the TX processing circuitry  215  in accordance with well-known principles. In some embodiments, the processor  240  includes at least one microprocessor or microcontroller. 
     The processor  240  is also capable of executing other processes and programs resident in the memory  260 . The processor  240  can move data into or out of the memory  260  as required by an executing process. In some embodiments, the processor  240  is configured to execute the applications  262  based on the OS program  261  or in response to signals received from eNBs, other UEs, or an operator. The processor  240  is also coupled to the I/O interface  245 , which provides the UE  114  with the ability to connect to other devices such as laptop computers and handheld computers. The I/O interface  245  is the communication path between these accessories and the processor  240 . 
     The processor  240  is also coupled to the input  250  (e.g., touchscreen, keypad, etc.) and the display  255 . The operator of the UE  114  can use the input  250  to enter data into the UE  114 . The display  255  may be a liquid crystal display or other display capable of rendering text and/or at least limited graphics, such as from web sites. The display  255  could also represent a touch-screen. 
     The memory  260  is coupled to the processor  240 . Part of the memory  260  could include a broadcast signaling memory (RAM), and another part of the memory  260  could include a Flash memory or other read-only memory (ROM). 
     As described in more detail below, the transmit and receive paths of the UE  114  support transmitting a PUCCH with repetitions and frequency retuning and support performing frequency error correction based on reception of channels transmitted with repetitions. In certain embodiments, the TX processing circuitry  215  and RX processing circuitry  225  include processing circuitry configured to support transmission of a PUCCH with repetitions and to perform frequency error correction based on received repetitions of a channel. In certain embodiments, the processor  240  is configured to control the RF transceivers  210 , the TX processing circuitry  215 , or the RX processing circuitry  225 , or a combination thereof, to support transmission of a PUCCH with repetitions and perform frequency error correction based on received repetitions of a channel. 
     Although  FIG. 2  illustrates one example of UE  114 , various changes can be made to  FIG. 2 . For example, various components in  FIG. 2  could be combined, further subdivided, or omitted and additional components could be added according to particular needs. As a particular example, the processor  240  could be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Also, while  FIG. 2  illustrates the UE  114  configured as a mobile telephone or smart-phone, UEs could be configured to operate as other types of mobile or stationary devices. In addition, various components in  FIG. 2  could be replicated, such as when different RF components are used to communicate with the eNBs  101 - 103  and with other UEs. 
       FIG. 3  illustrates an example eNB  102  according to this disclosure. The embodiment of the eNB  102  shown in  FIG. 3  is for illustration only, and other eNBs of  FIG. 1  could have the same or similar configuration. However, eNBs come in a wide variety of configurations, and  FIG. 3  does not limit the scope of this disclosure to any particular implementation of an eNB. 
     As shown in  FIG. 3 , the eNB  102  includes multiple antennas  305   a - 305   n , multiple RF transceivers  310   a - 310   n , transmit (TX) processing circuitry  315 , and receive (RX) processing circuitry  320 . The eNB  102  also includes a controller/processor  325 , a memory  330 , and a backhaul or network interface  335 . 
     The RF transceivers  310   a - 310   n  receive, from the antennas  305   a - 305   n , incoming RF signals, such as signals transmitted by UEs or other eNBs. The RF transceivers  310   a - 310   n  down-convert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals are sent to the RX processing circuitry  320 , which generates processed baseband signals by filtering, decoding, and/or digitizing the baseband or IF signals. The RX processing circuitry  320  transmits the processed baseband signals to the controller/processor  325  for further processing. 
     The TX processing circuitry  315  receives analog or digital data (such as voice data, web data, e-mail, or interactive video game data) from the controller/processor  325 . The TX processing circuitry  315  encodes, multiplexes, and/or digitizes the outgoing baseband data to generate processed baseband or IF signals. The RF transceivers  310   a - 310   n  receive the outgoing processed baseband or IF signals from the TX processing circuitry  315  and up-converts the baseband or IF signals to RF signals that are transmitted via the antennas  305   a - 305   n.    
     The controller/processor  325  can include one or more processors or other processing devices that control the overall operation of the eNB  102 . For example, the controller/processor  325  could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers  310   a - 310   n , the RX processing circuitry  320 , and the TX processing circuitry  315  in accordance with well-known principles. The controller/processor  325  could support additional functions as well, such as more advanced wireless communication functions. For instance, the controller/processor  325  could support beam forming or directional routing operations in which outgoing signals from multiple antennas  305   a - 305   n  are weighted differently to effectively steer the outgoing signals in a desired direction. Any of a wide variety of other functions could be supported in the eNB  102  by the controller/processor  325 . In some embodiments, the controller/processor  325  includes at least one microprocessor or microcontroller. 
     The controller/processor  325  is also capable of executing programs and other processes resident in the memory  330 , such as an OS. The controller/processor  325  can move data into or out of the memory  330  as required by an executing process. 
     The controller/processor  325  is also coupled to the backhaul or network interface  335 . The backhaul or network interface  335  allows the eNB  102  to communicate with other devices or systems over a backhaul connection or over a network. The interface  335  could support communications over any suitable wired or wireless connection(s). For example, when the eNB  102  is implemented as part of a cellular communication system (such as one supporting 5G, LTE, or LTE-A), the interface  335  could allow the eNB  102  to communicate with other eNBs over a wired or wireless backhaul connection. When the eNB  102  is implemented as an access point, the interface  335  could allow the eNB  102  to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The interface  335  includes any suitable structure supporting communications over a wired or wireless connection, such as an Ethernet or RF transceiver. 
     The memory  330  is coupled to the controller/processor  325 . Part of the memory  330  could include a RAM, and another part of the memory  330  could include a Flash memory or other ROM. 
     As described in more detail below, the receive paths of the eNB  102  support reception of a PUCCH transmitted with repetitions and frequency retuning and support performing frequency error correction based on reception of channels transmitted with repetitions. In certain embodiments, the TX processing circuitry  315  and RX processing circuitry  320  include processing circuitry configured to support reception of a PUCCH transmitted with repetitions and frequency retuning and to support frequency error correction based on received repetitions of a channel. In certain embodiments, the processor  240  is configured to control the RF transceivers  310   a - 310   n , TX processing circuitry  315  or RX processing circuitry  320 , or a combination thereof, to support reception of a PUCCH transmitted with repetitions and frequency retuning and to support frequency error correction based on received repetitions of a channel. 
     Although  FIG. 3  illustrates one example of an eNB  102 , various changes can be made to  FIG. 3 . For example, the eNB  102  could include any number of each component shown in  FIG. 3 . As a particular example, an access point could include a number of interfaces  335 , and the controller/processor  325  could support routing functions to route data between different network addresses. As another particular example, while shown as including a single instance of TX processing circuitry  315  and a single instance of RX processing circuitry  320 , the eNB  102  could include multiple instances of each (such as one per RF transceiver). 
     A transmission time interval (TTI) for DL signaling or UL signaling is referred to as a subframe (SF) and includes two slots. A slot includes seven SF symbols when a normal cyclic prefix (CP) is used or six SF symbols when an extended CP is used (see also REF 1). A unit of ten SFs is referred to as a frame. A bandwidth (BW) unit is referred to as a resource block (RB), one RB over one slot is referred to as a physical RB (PRB) and one RB over one SF is referred to as a PRB pair. 
     In some wireless networks, DL signals include data signals conveying information content, control signals conveying DL control information (DCI), and reference signals (RS) that are also known as pilot signals. The eNB  102  transmits data information through respective physical DL shared channels (PDSCHs). The eNB  102  also transmits DCI through respective physical DL control channels (PDCCHs). The eNB  102  can transmit one or more of multiple types of RS including a UE-common RS (CRS), a channel state information RS (CSI-RS), and a demodulation RS (DMRS)—see also REF 1. The eNB  102  transmits a CRS over a DL system BW and the CRS can be used by UEs to demodulate data or control signals or to perform measurements. To reduce CRS overhead, the eNB  102  can transmit a CSI-RS with a smaller density in the time and/or frequency domain than a CRS. UE  114  can determine CSI-RS transmission parameters, when applicable, through higher layer signaling from eNB  102 . DMRS is transmitted only in the BW of a respective PDSCH or PDCCH and UE  114  can use the DMRS to demodulate information in the PDSCH or the PDCCH. DL signals also include transmission of channels that convey system information (SI) such as a physical broadcast channel (PBCH) that conveys a master information block (MIB) or PDSCHs that convey system information blocks (SIBS)—see also REF 3 and REF 5. 
     Information symbols (data or control) in PBCH, PDSCH, or PDCCH transmission are scrambled with a scrambling sequence. For example, for each codeword  q , a block of encoded data bits b (q) (0), . . . , b (q) (M bit   (q) −1), where M bit   (q)  is a number of bits in codeword  q  transmitted on a physical channel in a SF, is scrambled prior to modulation (see also REF 1). 
     In some wireless networks, UL signals include data signals conveying data information, control signals conveying UL control information (UCI), and UL RS. UE  114  transmits data information or UCI through a respective physical UL shared channel (PUSCH) or a physical UL control channel (PDCCH). When UE  114  needs to transmit data information and UCI in a same SF, UE  114  can multiplex both in a PUSCH. The UCI includes HARQ acknowledgement (HARQ-ACK) information indicating correct (ACK) or incorrect (NACK) detection for data transport block (TB) in a PDSCH, or absence of a PDCCH detection (DTX), scheduling request (SR) indicating whether UE  114  has data in its buffer, and channel state information (CSI) enabling eNB  102  to select appropriate parameters for PDSCH transmissions to UE  114 . HARQ-ACK information is also transmitted by UE  114  in response to a detection of a PDCCH indicating a release of semi-persistently scheduled (SPS) PDSCH (see also REF 3). For brevity, this is not explicitly mentioned in the following descriptions. In addition to the CSI, UE  114  can provide to eNB  102  a reference signal received power (RSRP) information through a medium access control (MAC) element in a PUSCH transmission. 
     UL RS includes DMRS and sounding RS (SRS). UE  114  transmits DMRS only in a BW of a respective PUSCH or PUCCH. The eNB  102  can use a DMRS to demodulate data signals or UCI signals. A DMRS is transmitted using a Zadoff-Chu (ZC) sequence having a cyclic shift (CS) and an orthogonal covering code (OCC) that eNB  102  can inform to UE  114  through a respective UL DCI format (see also REF 2) or configure by higher layer signaling. UE  114  transmits SRS to provide eNB  102  with an UL CSI. SRS transmission can be periodic (P-SRS) at predetermined SFs, with parameters configured to UE  114  from eNB  102  by higher layer signaling, or aperiodic (A-SRS) as triggered by a DCI format scheduling PUSCH (UL DCI format) or PDSCH (DL DCI format) (see also REF 2 and REF 3). 
     Information symbols (data or control) in a PUSCH or PUCCH transmission are scrambled with a scrambling sequence. For example, a block of encoded data bits b (q) (0), . . . , b (q) (M bit   (q) −1), where M bit   (q)  is a number of bits transmitted in codeword  q  on a PUSCH in a SF, is scrambled with a UE-specific scrambling sequence prior to modulation (see also REF 1). 
       FIG. 4  illustrates an example UL SF structure for PUSCH transmission or PUCCH transmission according to this disclosure. The embodiment of the UL SF structure shown in  FIG. 4  is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure. 
     In the example shown in  FIG. 4 , an UL SF  410  includes two slots  420 . Each slot  420  includes N symb   UL  symbols  430  for transmitting data information, UCI, DMRS, or SRS. Each RB includes N sc   RB  sub-carriers (SCs). UE  114  is allocated N RB   UL  RBs  440  for a total of N RB   UL ·N sc   RB  SCs for a transmission BW. For a PUCCH, N RB   UL =1. A last SF symbol can be used to multiplex SRS transmissions  450  from one or more UEs. A number of SF symbols that are available for data/UCI/DMRS transmission is N symb =2·(N symb   UL −1)−N SRS , where N SRS =1 when a last SF symbol is used to transmit SRS and N SRS =0 otherwise. Each element in the time-frequency resource grid is called a resource element (RE) and is uniquely defined by the index pair (k,l) in a slot where k=0, . . . , N RB   UL N sc   RB −1 and l=0, . . . , N symb −1 are the indices in the frequency and time domains, respectively. 
       FIG. 5  illustrates a UE transmitter block diagram for a PUSCH in a SF according to this disclosure. The embodiment of the UE PUSCH transmitter block diagram shown in  FIG. 5  is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure. 
     Information data bits  510  are encoded by encoder  520 , such as a turbo encoder, scrambled by scrambler  525 , and modulated by modulator  530  to output data symbols. A discrete Fourier transform (DFT) filter  540  applies a DFT on the data symbols, SCs  550  corresponding to an assigned PUSCH transmission BW are selected by transmission BW selection unit  555 , filter  560  applies an inverse fast Fourier transform (IFFT) and, after a CP insertion (not shown), filtering is applied by filter  570  and a signal transmitted  580 . Encoding of a data TB can be by using incremental redundancy, in case of retransmissions of the data TB, and an associated redundancy version (see also REF 2). 
       FIG. 6  illustrates an eNB receiver block diagram for a PUSCH in a SF according to this disclosure. The embodiment of the eNB receiver block diagram for a PUSCH shown in  FIG. 6  is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure. 
     A received signal  610  is filtered by filter  620 . Subsequently, after a CP is removed (not shown), filter  630  applies a fast Fourier transform (FFT), SCs  640  corresponding to an assigned PUSCH reception BW are selected by a reception BW selector  645 , unit  650  applies an inverse DFT (IDFT), a demodulator  660  coherently demodulates data symbols by applying a channel estimate obtained from a DMRS (not shown), a descrambler descrambles the demodulated data symbols  665 , and a decoder  670 , such as a turbo decoder, decodes the demodulated data symbols according to an encoded redundancy version to provide information data bits  680 . 
       FIG. 7  illustrates a PUCCH structure for transmitting HARQ-ACK information or SR information in one slot of a SF according to this disclosure. The embodiment of the PUCCH structure shown in  FIG. 7  is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure. 
     Each slot  705  of a SF includes transmission of HARQ-ACK or SR signals  710  and of DMRS  720  in a RB. A HARQ-ACK symbol or a SR symbol b  730  is multiplied  740  by an element of a first orthogonal covering code (OCC)  750 , as is subsequently described, at each respective SF symbol and modulates  760  a ZC sequence  770  (see also REF 1). For SR transmission, b=1. A modulated ZC sequence is transmitted after performing an IFFT  780 . A DMRS is transmitted through an unmodulated ZC sequence that is multiplied by elements of a second OCC  790  at respective SF symbols. UE  114  can transmit both HARQ-ACK and SR in a same SF by selecting a resource configured for SR transmission and transmitting HARQ-ACK (see also REF 1 and REF 3). 
     Different CSs of a ZC sequence (see also REF 1) can provide orthogonal ZC sequences and can be allocated to different UEs to achieve orthogonal multiplexing of respective HARQ-ACK, SR, and RS transmissions in a same RB. Orthogonal multiplexing can also be achieved in the time domain using OCC. For example, in  FIG. 7 , a HARQ-ACK signal or a SR signal can be modulated by a length-4 OCC, such as a Walsh-Hadamard OCC, while a RS can be modulated by a length-3 OCC, such as a DFT OCC. When SRS is multiplexed in a last symbol of a SF, a length-3 OCC can also be used for a HARQ-ACK signal or a SR signal. In this manner, a PUCCH multiplexing capacity per RB is increased by a factor of 3 (determined by the OCC with the smaller length). A PUCCH resource n PUCCH  in a RB is defined by a pair of an OCC n oc  and a CS α. A UE can determine a PUCCH resource either implicitly (see also REF 3) or explicitly by radio resource control (RRC) signaling from eNB  102 . The sets of length-4 OCC and length-3 OCC, {W 0 , W 1 , W 2 , W 3 } and {D 0 , D 1 , D 2 } respectively, are: 
     
       
         
           
             
               
                 [ 
                 
                   
                     
                       
                         W 
                         0 
                       
                     
                   
                   
                     
                       
                         W 
                         1 
                       
                     
                   
                   
                     
                       
                         W 
                         2 
                       
                     
                   
                   
                     
                       
                         W 
                         3 
                       
                     
                   
                 
                 ] 
               
               = 
               
                 [ 
                 
                   
                     
                       1 
                     
                     
                       1 
                     
                     
                       1 
                     
                     
                       1 
                     
                   
                   
                     
                       1 
                     
                     
                       
                         - 
                         1 
                       
                     
                     
                       1 
                     
                     
                       
                         - 
                         1 
                       
                     
                   
                   
                     
                       1 
                     
                     
                       1 
                     
                     
                       
                         - 
                         1 
                       
                     
                     
                       
                         - 
                         1 
                       
                     
                   
                   
                     
                       1 
                     
                     
                       
                         - 
                         1 
                       
                     
                     
                       
                         - 
                         1 
                       
                     
                     
                       1 
                     
                   
                 
                 ] 
               
             
             , 
             
               
                 [ 
                 
                   
                     
                       
                         D 
                         0 
                       
                     
                   
                   
                     
                       
                         D 
                         1 
                       
                     
                   
                   
                     
                       
                         D 
                         2 
                       
                     
                   
                 
                 ] 
               
               = 
               
                 
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                         1 
                       
                       
                         1 
                       
                     
                     
                       
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                 . 
               
             
           
         
       
     
     Table 1 presents a mapping for a PUCCH resource n PUCCH  to an OCC n oc  and a CS α assuming a total of 12 CS per SF symbol for a ZC sequence. When all resources within a PUCCH RB are used, resources in an immediately next RB can be used. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 PUCCH Resource Mapping to OCC and CS 
               
            
           
           
               
               
            
               
                   
                 OCC n oc   
               
            
           
           
               
               
               
               
            
               
                 CS α 
                 W 0 , D 0   
                 W 1 , D 1   
                 W 3 , D 2   
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 0 
                 n PUCCH  = 0 
                   
                 n PUCCH  = 12 
               
               
                 1 
                   
                 n PUCCH  = 6 
               
               
                 2 
                 n PUCCH  = 1 
                   
                 n PUCCH  = 13 
               
               
                 3 
                   
                 n PUCCH  = 7 
               
               
                 4 
                 n PUCCH  = 2 
                   
                 n PUCCH  = 14 
               
               
                 5 
                   
                 n PUCCH  = 8 
               
               
                 6 
                 n PUCCH  = 3 
                   
                 n PUCCH  = 15 
               
               
                 7 
                   
                 n PUCCH  = 9 
               
               
                 8 
                 n PUCCH  = 4 
                   
                 n PUCCH  = 16 
               
               
                 9 
                   
                 n PUCCH  = 10 
               
               
                 10 
                 n PUCCH  = 5 
                   
                 n PUCCH  = 17 
               
               
                 11 
                   
                 n PUCCH  = 11 
               
               
                   
               
            
           
         
       
     
       FIG. 8  illustrates a UE transmitter block diagram for HARQ-ACK information or SR information in a PUCCH according to this disclosure. The embodiment of the UE transmitter block diagram shown in  FIG. 8  is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure. 
     A ZC sequence  810  is generated in the frequency-domain. A first RB and a second RB are selected by controller  820  for transmission  830  of the ZC sequence in a first slot and in a second slot, respectively, an IFFT is performed by IFFT filter  840 , and a CS applies to the output by CS mapper  850  that is then multiplied by multiplier  860  with an element of an OCC  870  for a respective SF symbol. As the operations are linear, the multiplication by the element of the OCC can also apply at any other step of the transmitting steps (for example, as in  FIG. 7 ). The multiplication by “1” or “−1” can also be implemented by keeping or reversing a signal sign, respectively. The resulting signal is filtered by filter  880  and transmitted  890 . 
       FIG. 9  illustrates an eNB receiver block diagram for HARQ-ACK information or SR information in a PUCCH according to this disclosure. The embodiment of the eNB receiver block diagram shown in  FIG. 9  is for illustration only. Other embodiments could be used without departing from the scope of the present disclosure. 
     A received signal  910  is filtered by filter  920  and an output is multiplied by multiplier  930  with an element of an OCC  940  for a respective SF symbol. A multiplication by an element of an OCC can apply at any part of the receiving steps. Subsequently, a CS applied at a transmitter is restored by CS demapper  950 , a FFT is performed by FFT filter  960 , a first RB or a second RB  970  in a first slot or in a second slot, respectively, is selected by controller  975 , and a signal is correlated by correlator  980  with a replica  990  of a ZC sequence. An output  995  can then be passed to a channel estimation unit, such as a time-frequency interpolator, in case of the RS, or to a detection unit in case of HARQ-ACK or SR. 
     Machine type communications (MTC) or Internet of Things (IoT) refers to communication of automated devices in a network. Compared to typical human communication, MTC typically has relaxed latency and quality of service (QoS) requirements and often does not require mobility support. However, MTC also requires that respective UEs have reduced cost and reduced power consumption compared to UEs serving human communications. MTC can be used for a wide variety of applications in different sectors including healthcare, such as monitors, industrial, such as safety and security, energy, such as meters and turbines, transport, such as fleet management and tolls, and consumer and home, such as appliances and power systems. 
     The requirements of reduced power consumption or low cost for UEs supporting MTC, that can be realized by limiting a power amplifier gain or reducing a number of receiver antennas, can lead to reduced coverage relative to UEs serving human communications. Coverage can be further degraded due to locations of UEs serving MTC that can often be in basements of buildings or, in general, where propagation of radio signals experiences substantial path-loss. For these reasons, supporting coverage enhancements (CE) for transmissions to or from UEs serving MTC is an essential feature for a communication system supporting MTC. In scenarios requiring large CE, communications typically have characteristics of low data rate, delay tolerance, and limited UE mobility. Not all UEs require CE or require a same level of CE. Also, coverage limited UEs typically require low power consumption and communicate with infrequent small burst transmissions. In addition, in different deployment scenarios, a required CE level can be different for different eNBs depending, for example, on an eNB transmission power, or a number of eNB receiver antennas, or an associated cell size, as well as for different UEs, for example depending on a location of a UE or on a power amplifier class of a UE. 
     Support for CE is typically enabled by repeating transmissions either in the time domain or also in the frequency domain at least in the DL. In the UL, in order to maximize or increase a power spectral density when UE  114  is coverage limited, repetitions of a transmission are typically in one RB and with a maximum transmission power. Since support for CE consumes additional resources and results to lower spectral efficiency or increased power consumption, it is beneficial to enable adjustments of resources according to a required CE level while minimizing or reducing UE power consumption. 
     For cost reduction purposes, UEs can transmit only in a small BW, such as in a maximum of 6 RBs, and can receive only in a small BW, such as in a maximum of 6 RBs. A BW of 6 consecutive RBs is referred to as a narrowband. Frequency hopping (FH) for a channel transmission can provide significant gains in reception reliability and reduce a number of repetitions for achieving a CE level. For a PUCCH transmission from UE  114  that can only transmit within a narrowband of 6 RBs, FH over a system BW larger than 6 RBs requires that UE  114  transmitter retunes its radio frequency to a different narrowband. Such retuning is associated with a delay that can be as large as 2 SF symbols. 
     PDCCH/PDSCH transmissions to UE  114  requiring CE can use most or all of the 6 RBs of a narrowband in order to reduce a number of repetitions. As a consequence, few UEs are typically expected to transmit HARQ-ACK repetitions over a set of one or more SFs in response to respective PDCCH/PDSCH receptions. It is therefore beneficial for PUCCH resources used for HARQ-ACK transmission or SR transmission to be shared among UEs that can require different CE levels in order to avoid using multiple RBs to multiplex only few UEs of same CE level per RB and to avoid introducing unnecessary overhead in an UL system BW. However, due to existence of timing errors, near-far effects can exist when UEs requiring different CE levels multiplex respective HARQ-ACK transmissions or SR transmissions using different respective OCCs in a same RB. 
     The eNB  102  can configure UE  114  a number of repetitions for a transmission or for a reception of a channel in order to achieve a target CE level. For example, eNB  102  can configure UE  114  a first number of SFs for reception of PDSCH repetitions, a second number of SFs for transmission of PUSCH repetitions, and so on. For a PDSCH transmission scheduled by a DL DCI format or for a PUSCH transmission scheduled by an UL DCI format, eNB  102  can indicate a number of repetitions, among a configured set of numbers of repetitions, through a field in the DL DCI format or the UL DCI format, respectively. 
     Although repetitions for a PUSCH transmission or for a PUCCH transmission can improve a SINR for data symbols or control symbols after combining of repetitions, detection reliability is still limited by a reliability of a channel estimate used for coherent demodulation of the data symbols or of the control symbols. It is therefore important to enhance channel estimation reliability as this can result to a significant reduction in a number of required PUSCH repetitions or PUCCH repetitions, thereby reducing power consumption for UE  114  and improving system spectral efficiency. 
     Enhanced channel estimation reliability can be achieved by DMRS filtering across SFs used for repetitions of a channel transmission. However, such filtering is limited by a frequency offset between UE  114  and eNB  102  when UE  114  is quasi-stationary and does not experience a Doppler shift as it is typically the case when UE  114  requires CE. Assuming a maximum frequency error of 0.05 parts per million (ppm) for a local oscillator (LO) at eNB  102  and of 0.1 ppm for a LO at UE  114  and a carrier frequency of 2 GHz, a maximum frequency offset due to the LO errors is 300 Hz. Such a frequency offset results to a phase shift over one SF of 2π×300 (Hz)×1e−3 (sec)=3π/5 that is large enough to preclude inter-SF DMRS filtering and even limit benefits from intra-SF DMRS filtering. 
     One approach for eNB  102  to estimate and correct a frequency offset is to correlate, in time or in frequency, successive PUSCH DMRS transmitted from UE  114 . Similar, UE  114  can use a CRS or a DMRS to estimate and correct a frequency offset. A frequency offset estimate, f offset , can be obtained as f offset =∠ρ/(2π·T) where ∠ρ is a phase of a correlation ρ and T is a time interval between DMRS symbols such as 0.5e−3 seconds when DMRS is placed in a middle symbol in each slot of a SF as in  FIG. 4 . A receiver can apply a frequency offset correction prior to channel estimation and demodulation. For example, in  FIG. 9 , the eNB  102  receiver can apply a frequency offset correction after the IDFT and prior to the demodulator. When UE  114  experiences a very low SINR, such as below −5 deciBell (dB), a value of ∠ρ is not reliable as it is can be dominated by noise and a frequency offset correction can actually increase an actual frequency offset. 
     Certain embodiments of this disclosure enable retuning for repetitions of a PUCCH transmission in RBs located in different narrowbands while maintaining a same PUCCH multiplexing capacity as when there is no retuning. Certain embodiments of this disclosure also enable multiplexing of HARQ-ACK transmissions or SR transmissions from UEs operating with different CE levels in a same RB during a same set of one or more SFs. Additionally, certain embodiments of this disclosure enable a frequency offset correction based on replicas of information symbols in repetitions of a channel transmission. Finally, certain embodiments of this disclosure enable an eNB to adjust a number of repetitions for a channel transmission depending on a correction of a frequency offset for the channel transmission. 
     A first embodiment of the disclosure considers a PUCCH structure incorporating a retuning delay. 
     UE  114  is assumed to be capable to transmit only within 6 RBs of an UL system BW and to receive only within 6 RBs of a DL system BW at a given time instance. To enable FH for repetitions of a PUCCH transmission in different narrowbands, UE  114  needs to retune its transmitter to a frequency of a RB in a narrowband after FH. This retuning requires a delay that can be as large as 2 SF symbols. In addition to providing frequency diversity, improving an accuracy of a channel estimate used for coherent demodulation of HARQ-ACK symbols or SR symbols in a PUCCH can result to significant enhancements in respective reception reliability. Such improvement can be achieved by enabling inter-SF RS filtering. Therefore, it is beneficial to use structure for a PUCCH transmission with repetitions that enables both FH for frequency diversity and inter-SF RS filtering for improved CE while avoiding reducing a PUCCH multiplexing capacity. 
       FIG. 10  illustrates a retuning structure for a PUCCH transmission with repetitions according to this disclosure. 
     The eNB  102  configures UE  114  to transmit repetitions of a PUCCH transmission over eight SFs. The PUCCH transmission can convey HARQ-ACK or SR. UE  114  transmits first four repetitions in respective first four SFs in a first PUCCH resource of a first RB in a first narrowband  1010 . UE  114  transmits second four repetitions in respective second four SFs in a second PUCCH resource of a second RB in a second narrowband  1020 . The first and second PUCCH resources can be considered as part of a single PUCCH resource that is separately defined in the first four SFs and in the second four SFs. For example, UE  114  can determine a PUCCH resource in the second four SFs from a first PUCCH resource in the first four SFs (see also REF 1). UE  114  suspends PUCCH transmission in a last symbol of a last SF of the first four SFs  1030  and in a first symbol of a first SF of the second four SFs  1040  in order to perform retuning from a frequency of the first RB in the first narrowband to a frequency of the second RB of the second narrowband for the PUCCH transmission. With the exception of the PUCCH transmission in the fifth SF, the PUCCH transmission in the other SFs can have a structure as in  FIG. 4  or in  FIG. 5  where transmission in a last symbol of a SF can be suspended in case SRS transmission is multiplexed or in case UE  114  needs to perform retuning. For the PUCCH structure in the fifth SF, transmission in a first SF symbol is suspended in order for the UE to perform retuning. 
     An advantage of partitioning two SF symbols required for UE  114  to retune between two narrowbands as in  FIG. 10  is that a PUCCH multiplexing capacity is not reduced. For example, when the two SF symbols are both placed in a same SF, a number of SF symbols that is available for HARQ-ACK transmission or SR transmission in a second slot of a last SF prior to retuning is equal to two (instead of three as in  FIG. 10 ). As a consequence, a smallest OCC length for orthogonal multiplexing of HARQ-ACK transmissions or SR transmissions from different UEs is two resulting to a multiplexing capacity of two UEs across the OCC domain (UEs using a same CS and different OCCs). For example, for 6 available CS, a UE multiplexing capacity for HARQ-ACK transmissions or SR transmissions in a RB would be reduced from 3×6=18 as in  FIG. 7  (or  FIG. 11  below) to 2×6=12 when both SF symbols required for retuning are placed in a same SF such as the fourth SF (last SF prior to retuning) or the fifth SF (first SF after retuning) in  FIG. 10 . 
       FIG. 11  illustrates a PUCCH transmission structure where transmission a first SF symbol is suspended according to this disclosure. 
     A PUCCH transmission structure is similar to the one in  FIG. 7  and descriptions for functionalities with direct correspondence are omitted for brevity. In a first slot  1110  of a SF that includes two slots, UE  114  suspends HARQ-ACK transmission or SR transmission in a PUCCH in a first symbol  1120 . UE  114  transmits HARQ-ACK or SR in 3 symbols of the first slot  1130  and transmits RS in remaining 3 symbols  1140  of the first slot (and also in the second slot of the SF). UE  114  uses an OCC of length-3  1150  to transmit HARQ-ACK or SR in the 3 symbols of the slot. The OCC can be same as the OCC for the RS  1160 . 
     When FH for repetitions of a PUCCH transmission between a first narrowband and a second narrowband applies more than once and retuning is needed from the second narrowband to the first narrowband, the structures in  FIG. 10  and  FIG. 11  remain applicable as the second narrowband is now the first narrowband and the first narrowband is now the second narrowband since retuning is now from the second narrowband to the first narrowband. Then, for retuning, a PUCCH transmission is punctured in the last SF symbol of the last repetition in the second narrowband and in the first SF symbol of the first repetition in the first narrowband. 
     A second embodiment of the disclosure considers multiplexing HARQ-ACK transmissions or SR transmissions with different numbers of repetitions for different CE levels. 
     An ability to multiplex, in a same RB of a PUCCH, repetitions of HARQ-ACK transmissions or of SR transmissions with different numbers of repetitions from UEs requiring different CE levels is limited by the near-far effect that can occur due to timing differences among the transmissions at the eNB  102  receiver. Then, signaling from a first UE requiring a larger CE level can experience substantial interference from signaling from a second UE requiring a lower CE level and a probability for an incorrect decision by eNB  102  for a HARQ-ACK or a SR for the first UE significantly increases. 
     In a given SF, a number of UEs transmitting HARQ-ACK or SR with repetitions in a PUCCH is typically not large. Therefore, maximizing or increasing a PUCCH multiplexing capacity per CE level is not an optimal design when PUCCH transmissions from only a few UEs with a same CE level are multiplexed in a same RB and PUCCH transmissions from UEs with different CE levels are multiplexed in different RBs in a SF. Instead, it is preferable to use a same RB to multiplex PUCCH transmissions from UEs requiring different CE levels even when a reduction in the PUCCH multiplexing capacity occurs. For example, when 2 UEs requiring a first CE level (first number of repetitions), 2 UEs requiring a second CE level (second number of repetitions), and 1 UE requiring a third CE level (third number of repetitions) transmit HARQ-ACK or SR in a PUCCH in a same SF, it is preferable to multiplex all respective PUCCH transmissions (conveying HARQ-ACK or SR) in a same RB instead of using a separate RB for each CE level. 
     A near-far effect that occurs when PUCCH transmissions from UEs requiring different CE levels are multiplexed in a same RB during a same SF can be suppressed by eliminating time-domain multiplexing based on a use of different OCCs. Instead, only multiplexing in a CS domain can apply. A PUCCH multiplexing capacity in a RB is reduced by a factor equal to the smaller OCC length, such as a factor of 3, but such reduction is acceptable when a total number of UEs requiring different CE levels and having PUCCH transmission in a same SF is smaller than or equal to a number of CS that can be used for multiplexing PUCCH transmissions in a same RB during a same SF. Therefore, the disclosure considers disabling OCC-based multiplexing and using only CS-based multiplexing for PUCCH transmissions conveying HARQ-ACK or SR. 
     Table 2 presents an exemplary mapping for a PUCCH resource n PUCCH  to a CS α assuming that an OCC of all ones (equivalent to no OCC) applies to SF symbols used for HARQ-ACK or SR transmission or for RS transmission. Other mappings can also be used such as, for example, mapping a CS to a PUCCH resource in an ascending order where CS=0 is mapped to n PUCCH =0, CS=1 is mapped to n PUCCH =1, and so on. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 PUCCH Resource Mapping to CS 
               
            
           
           
               
               
            
               
                   
                 PUCCH resource 
               
               
                 CS α 
                 n PUCCH   
               
               
                   
               
            
           
           
               
               
            
               
                 0 
                 n PUCCH  = 0 
               
               
                 1 
                 n PUCCH  = 6 
               
               
                 2 
                 n PUCCH  = 1 
               
               
                 3 
                 n PUCCH  = 7 
               
               
                 4 
                 n PUCCH  = 2 
               
               
                 5 
                 n PUCCH  = 8 
               
               
                 6 
                 n PUCCH  = 3 
               
               
                 7 
                 n PUCCH  = 9 
               
               
                 8 
                 n PUCCH  = 4 
               
               
                 9 
                 n PUCCH  = 10 
               
               
                 10 
                 n PUCCH  = 5 
               
               
                 11 
                 n PUCCH  = 11 
               
               
                   
               
            
           
         
       
     
       FIG. 12  illustrates a PUCCH structure for transmitting HARQ-ACK information or SR information in one slot of a SF without multiplication by an OCC according to this disclosure. 
     The operations in  FIG. 12  are same with the ones in  FIG. 7  except that a multiplication by elements of an OCC is not applied to SF symbols used for HARQ-ACK or SR transmission or for RS transmission. Each slot  1205  includes transmission of HARQ-ACK signals or SR signals  1210  and RS  1220  in a RB. An HARQ-ACK symbol b  1230  modulates  1240  a ZC sequence  1250 . The modulated ZC sequence is transmitted after performing an IFFT  1260 . For SR transmission, b=1. A RS is transmitted through an unmodulated ZC sequence.  FIG. 12  can also be combined with  FIG. 11  to result to a transmission structure over one slot where UE  114  suspends PUCCH transmission (and eNB  102  suspends PUCCH reception) in a first SF symbol (in addition to possible suspension in a last SF symbol). 
       FIG. 13  illustrates a UE transmitter for HARQ-ACK or SR information in a PUCCH without multiplication of HARQ-ACK or SR symbols or of RS symbols with an OCC according to this disclosure. 
     A ZC sequence is generated in the frequency-domain  1310 . A first RB and a second RB are selected  1320  for transmission  1330  of the ZC sequence in a first slot and in a second slot, respectively, an IFFT is performed by IFFT filter  1340 , and a CS mapper applies a CS to the output of the IFFT  1350 . Subsequently, the signal is filtered by filter  1360  and transmitted  1370 . 
       FIG. 14  illustrates an eNB receiver for HARQ-ACK or SR information in a PUCCH without multiplication of HARQ-ACK or SR symbols or of RS symbols with an OCC according to this disclosure. 
     A received signal  1410  is filtered by filter  1420 . Subsequently, a CS applied at a transmitter is restored by CS demapper  1430 , a FFT is applied by FFT filter  1440 , a first RB or a second RB  1450  in a first slot or in a second slot, respectively, is selected by controller  1455 , and a signal is correlated by correlator  1460  with a replica  1470  of a ZC sequence. An output  1475  can then be passed to a channel estimation unit, such as a time-frequency interpolator, in case of the RS, or to a detection unit in case of HARQ-ACK or SR. 
     A third embodiment of the disclosure considers a frequency offset determination based on correlations of signal replicas received over multiple SFs. An exemplary realization considers a frequency offset determination at eNB  102  based on correlations of PUSCH DMRS replicas received over multiple SFs but the same principle can apply either at an eNB  102  receiver or at a UE  114  receiver using received replicas of any other signal. For brevity, the third embodiment of the disclosure is described with reference to the eNB  102  receiver. 
     The eNB  102  receiver can estimate a frequency offset for a reception of a channel from UE  114  (cumulative frequency offset due to frequency offsets at UE  114  transmitter and eNB  102  receiver) as an average of individual frequency offset estimates obtained from correlations among DMRS in a PUSCH reception over a number of repetitions in respective SFs. Denoting by N PUSCH  a number of repetitions over a respective number of SFs for a PUSCH transmission from UE  114 , an eNB  102  receiver can use the DMRS in N PUSCH,1 ≤N PUSCH  repetitions to determine a frequency offset. When UE  114  requires CE operation, UE  114  typically has limited mobility (including no mobility) and a phase introduced by a frequency offset changes linearly with time (but can be interpreted modulo 2π). Therefore, a correlation among DMRS symbols to obtain a frequency offset estimate need not be limited to successive DMRS symbols in time. 
     For brevity, the following descriptions consider that correlations among DMRS symbols can be over two successive DMRS symbols but any number of successive DMRS symbols can apply. Denoting by T 0  a slot duration, for example T 0 =0.5e−3 seconds, and by T 1  a SF duration, for example T 1 =1e−3 seconds, a phase shift over a SF is T 1 /T 0  times larger than a phase shift over a slot. For 0≤i&lt;N PUSCH,1 −1, assuming correlation among DMRS symbols in the time domain (similar arguments apply for correlation among DMRS symbols in the frequency domain across SCs) and denoting by p i,0  a received DMRS symbol in the first slot of SF i, by p i,1  a received DMRS symbol in the second slot of SF i, and by p i+1,0  a received DMRS symbol in a first slot of SF i+1, a first frequency offset estimate can be obtained as {circumflex over (f)} offset (i,0,0)=∠ρ i,0,0 /(2π·T 0 ) or as {circumflex over (f)} offset (i,1,0)=∠ρ i,1,0 /(2π·T 0 ), where ρ i,0,0 =p i,0 ·p* i,1 , and ρ i,1,0 =p i,1 ·p* i+1,0 , where p* i,1 and p* i+1,0 are respectively the complex conjugates of p i,1  and p i+1,0 . A second frequency offset can be obtained as {circumflex over (f)} offset (i,0,1)=∠ρ i,0,1 /(2π·T 1 ) or as {circumflex over (f)} offset (i,1,1)=∠ρ i,1,1 /(2π·T 1 ), where ρ i,0,1 =p i,0 ·p* i+1,0 and ρ i,1,1 =p i,1 ·p* i+1,1 . Therefore, a frequency offset estimate can be obtained as 
     
       
         
           
             
               
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     It is also possible for eNB  102  to compute the correlations ρ i,j,0  and ρ i,j,1 , 0≤i&lt;N PUSCH,1 −1 and 0≤j≤1, obtain a first average correlation as 
                 ρ   ~     ⁡     (   0   )       =       1     2   ·     (       N     PUSCH   ,   1       -   1     )         ⁢       ∑     i   =   0         N     PUSCH   ,   1       -   1       ⁢       ∑     j   =   0     1     ⁢     ρ     i   ,   j   ,   0                   
or as
 
                   ρ   ~     ⁡     (   0   )       =       1       2   ·     (       N     PUSCH   ,   1       -   1     )       +   1       ⁢     (       ρ         N     PUSCH   ,   1       -   1     ,   0   ,   0       ⁢       ∑     i   =   0         N     PUSCH   ,   1       -   1       ⁢       ∑     j   =   0     1     ⁢     ρ     i   ,   j   ,   0             )         ,         
a second average correlation as
 
                   ρ   ~     ⁡     (   1   )       =       1     2   ·     (       N     PUSCH   ,   1       -   1     )         ⁢       ∑     i   =   0         N     PUSCH   ,   1       -   1       ⁢       ∑     j   =   0     1     ⁢     ρ     i   ,   j   ,   1               ,         
a first frequency offset estimate as) {circumflex over (f)} offset (0)=∠{tilde over (ρ)}(0)/(2π·T 0 ), a second frequency offset estimate as {circumflex over (f)} offset (1)≤∠{tilde over (ρ)}(1)/(2π·T 1 ), and compute a final frequency offset estimate as {circumflex over (f)} offset =({circumflex over (f)} offset (0)+{circumflex over (f)} offset (1))/2. In general, different weights can be assigned for {circumflex over (f)} offset (0) and {circumflex over (f)} offset (1) and {circumflex over (f)} offset =w(0)·{circumflex over (f)} offset (0)+w(1)·{circumflex over (f)} offset (1) where w(0)+w(1)=1. As a phase of a correlation does not depend on a scaling for the correlation, scaling factors for computing {tilde over (ρ)}(0) or {tilde over (ρ)}(1) are optional.
 
     An extension for a correlation of a DMRS symbol with multiple other DMRS symbol, instead of only with an immediately next DMRS symbol, that is enabled from an assumption of limited/no mobility for UE  114  operating with CE resulting to a phase shift that can be uniquely attributed to a frequency offset (cumulative frequency offset due to frequency offsets at UE  114  transmitter and eNB  102  receiver), can result to a noise averaging when computing a frequency offset that can in turn result to a larger effective SINR and a more accurate frequency offset estimate. 
       FIG. 15  illustrates an example frequency offset estimation based on correlations across SCs of a DMRS symbol with subsequent DMRS symbols over three SFs according to this disclosure. 
     UE  114  transmits a PUSCH with 3 repetitions over respective SFs, SF# 0   1502 , SF# 1   1504 , and SF# 2   1506 . The eNB  102  receiver correlates a DMRS symbol in a first slot of SF# 0 , p 0,0 ,  1510  with a DMRS symbol in the second slot of SF# 0 , p 0,1 ,  1515  to obtain a first correlation ρ 0,0,0 =p 0,0 ·p* 0,1 and with a DMRS symbol in the first slot of SF# 1 , p 1,0 ,  1520  to obtain a second correlation ρ 0,0,1 =p 0,0 ·p* 1,0 /2. It is assumed that a time between a DMRS symbol in a first slot of a SF and a DMRS symbol in a first slot of an immediately next SF (one SF) is twice a time between a DMRS symbol in the first slot of the SF and a DMRS in a second slot of the SF (one slot). The eNB  102  receiver correlates the DMRS symbol in the second slot of SF# 0 , p 0,1 ,  1515  with the DMRS symbol in the first slot of SF# 1 , p 1,0 ,  1520  to obtain a third correlation ρ 0,1,0 =p 0,1 ·p* 1,0 and with the DMRS symbol in the second slot of SF# 1 , p 1,1 ,  1525  to obtain a fourth correlation ρ 0,1,1 =p 0,1 ·p* 1,1 /2. The eNB  102  receiver correlates the DMRS symbol in the first slot of SF# 1 , p 1,0 ,  1520  with the DMRS symbol in the second slot of SF# 1 , p 1,1 ,  1525  to obtain a fifth correlation ρ 1,0,0 =p 1,0 ·p* 1,1 and with the DMRS symbol in the first slot of SF# 2 , p 2,0 ,  1530  to obtain a sixth correlation ρ 1,0,1 =p 0,1 ·p* 1,1 /2. The eNB  102  receiver correlates the DMRS symbol in the second slot of SF# 1 , p 1,1 ,  1525  with the DMRS in the first slot of SF# 2 , p 2,0 ,  1530  to obtain a seventh correlation ρ 1,1,0 =p 1,1 ·p* 2,0 and with the DMRS in the second slot of SF# 2 , p 2,1 ,  1535  to obtain an eighth correlation ρ 1,1,1 =p 1,1 ·p* 2,1 /2. Finally, the eNB  102  receiver can correlate the DMRS symbol in the first slot of SF# 2 , p 2,0 ,  1530  with the DMRS symbol in the second slot of SF# 2 , p 2,1 ,  1535  to obtain a ninth correlation ρ 2,0,0 =p* 2,0 ·p 2,1 . The eNB  102  receiver can obtain a first average correlation as 
                 ρ   ~     ⁡     (   0   )       =       1     2   ·   2       ⁢       ∑     i   =   0     1     ⁢           ⁢       ∑     j   =   0     1     ⁢           ⁢     ρ     i   ,   j   ,   0                   
or as
 
                   ρ   ~     ⁡     (   0   )       =       1       2   ·   2     +   1       ⁢     (       ρ     2   ,   0   ,   0       +       ∑     i   =   0     1     ⁢           ⁢       ∑     j   =   0     1     ⁢           ⁢     ρ     i   ,   j   ,   0             )         ,         
a second
 
                   ρ   ~     ⁡     (   1   )       =       1     2   ·   2       ⁢       ∑     i   =   0     1     ⁢           ⁢       ∑     j   =   0     1     ⁢           ⁢     ρ     i   ,   j   ,   1               ,         
a first frequency offset estimate as {circumflex over (f)} offset (0)=∠{tilde over (ρ)}(0)/(2π·T 0 ), a second frequency offset estimate as {circumflex over (f)} offset (1)=∠{tilde over (ρ)}(1)/(2π·T 1 ), and can compute a final frequency offset estimate as {circumflex over (f)} offset =({circumflex over (f)} offset (0)+{circumflex over (f)} offset (1))/2.
 
     A fourth embodiment of the disclosure considers a frequency offset determination based on correlations of PUSCH DMRS symbols and PUSCH data symbols over multiple SFs. 
     The eNB  102  receiver can determine an estimate of a frequency offset (cumulative frequency offset due to frequency offsets at UE  114  transmitter and eNB  102  receiver) as an average of individual estimates obtained from symbol-by-symbol time-domain or frequency-domain correlations across SC that include both DMRS symbols and data symbols among SFs corresponding to repetitions of a PUSCH transmission. Denoting by N PUSCH  a number of repetitions over a respective number of SFs for a PUSCH transmission from UE  114 , the eNB  102  receiver can use both DMRS symbols and data symbols in N PUSCH,1 ≤N PUSCH  repetitions to obtain a frequency offset estimate. 
     The fourth embodiment considers that UE  114  applies a same redundancy version (see also REF 2) and same scrambling for data information in consecutive N PUSCH,2 ≤N PUSCH,1  repetitions of a PUSCH that UE  114  transmits with a same maximum power over respective N PUSCH,2 ≤N PUSCH,1  SFs. When UCI is multiplexed in the PUSCH transmission, same UCI symbols are repeated in consecutive N PUSCH,2  SFs for respective repetitions of the PUSCH transmission. When UE  114  punctures a transmission in a last PUSCH symbol in some SFs because UE  114  transmits SRS or other UEs transmit SRS that partially overlaps with the PUSCH transmission BW, the last SF symbol is not included in a correlation with last symbols in other SFs from the N PUSCH,2  SFs. When the last SF symbol is not included in the correlation and without considering SF symbols that can be used for retuning, there are J=13 SF symbols available for correlations, including DMRS symbols and data symbols for a SF structure using a normal CP (J=11 for a SF structure using extended CP); otherwise, J=14 (or J=12 for a SF structure using extended CP). 
     Even though values of modulated data symbols are not known to the eNB  102  receiver, they are not material for the purpose of estimating a frequency offset as a correlation of same modulated data symbols has a same value regardless of a value of same modulated data symbols. Denoting by d(j,i) a received signal across SCs in SF symbol j of SF i and by d(j,i+1) a received signal across SCs in symbol j of SF i+1, where 0≤j&lt;J and 0≤i&lt;N PUSCH,2 −1, the two signals convey same modulated data symbols as a same redundancy version for the data TB transmission and a same scrambling sequence for data symbols and DMRS symbols is assumed to be used in the consecutive N PUSCH,2  SFs. When symbol j conveys DMRS, there are no actual modulated data symbols but a same concept applies as the DMRS can be viewed as conveying a known modulated data symbol, for example having a numeric value of one. Then, a frequency offset estimate {circumflex over (f)} offset (i) derived from correlating modulated data symbols across SCs and DMRS symbols in SF i with modulated data symbols across SCs and DMRS symbols in SF i+1 can be obtained as {circumflex over (f)} offset (i)=∠{tilde over (ρ)}(i)/(2π·T 1′ ) where 
                 ρ   ~     ⁡     (   i   )       =       1   J     ·       ∑     j   =   0       J   -   1       ⁢           ⁢       d   ⁡     (     j   ,   i     )       ·       d   *     ⁡     (     j   ,     i   +   1       )                   
where d* is the complex conjugate of d and T 1  is the SF duration, for example T 1 =1e−3 seconds. Extending a computation of the correlation to M PUSCH,2 −1 SFs, a frequency offset estimate can be obtained as {circumflex over (f)} offset =∠{tilde over (ρ)}/(2π·T 1′ ) where
 
               ρ   ~     =       1     J   ·     (       N     PUSCH   ,   2       -   1     )         ·       ∑     i   =   0         N     PUSCH   ,   2       -   1       ⁢           ⁢       ∑     j   =   0       J   -   1       ⁢           ⁢       d   ⁡     (     j   ,   i     )       ·       d   *     ⁡     (     j   ,     i   +   1       )                     
(the scaling factor of 1/(N PUSCH,2 −1) is optional in determining a phase of {tilde over (ρ)}). A frequency offset estimation can also be extended by correlating across SCs (either in the time domain or in the frequency domain) received symbols in SF i with received symbols with same indexes in SF i+l, where l&gt;1.
 
       FIG. 16  illustrates an example frequency offset estimation based on correlations across SC of both DMRS symbols and data symbols in a PUSCH transmission over two SFs according to this disclosure. 
     UE  114  transmits a PUSCH with a number of repetitions where two repetitions from the number of repetitions are over SF# 0   1602  and SF# 1   1604 . An eNB  102  receiver performs a SF symbol by SF symbol correlation for SF# 0  and SF# 1  to obtain J individual correlations. For example, a first correlation is obtained across modulated data symbols or DMRS symbols in SCs of a first SF symbol of SF# 0  and in SCs of a first SF symbol of SF# 1   1610 , when available, a second correlation is obtained across modulated data symbols or DMRS symbols in SCs of a second SF symbol of SF# 0  and in SCs of a second SF symbol of SF# 1   1620 , and so on. As a time interval between SF symbol pairs in each of the J individual correlations is same (one SF), the correlations are equivalent and can be accumulated to provide an average correlation 
                 ρ   ~     ⁡     (   0   )       =       1   J     ·       ∑     j   =   0       J   -   1       ⁢           ⁢       d   ⁡     (     j   ,   0     )       ·         d   *     ⁡     (     j   ,   1     )       .                 
A frequency offset estimate {circumflex over (f)} offset (0) can be obtained as {circumflex over (f)} offset (0)=∠{tilde over (ρ)}(0)/(2π·T 1′ ) where T 1 =1e−3 seconds.
 
       FIG. 17  illustrates an example receiver structure for frequency offset estimation according to this disclosure. 
     A received signal  1710  is filtered by filter  1720 . Subsequently, after a CP is removed (not shown), filter  1730  applies a FFT, SCs  1740  corresponding to an assigned reception BW are selected by a reception BW selector  1745 , and unit  1750  applies an inverse DFT (IDFT). A buffer  1760  stores received modulated information symbols or RS symbols over a number of SF symbols and over a number of SCs of the assigned reception BW. A correlator  1770  correlates a symbol from a previous repetition with a symbol, for a same SF symbol and a same SC, of a new repetition for a same channel. An adder  1780  adds the correlations for the number of SF symbols and the number of SCs. A frequency offset estimator  1790  estimates a frequency offset based on the output of the adder  1780 . A frequency offset adjustor  1795  subsequently adjusts a reception frequency based on the estimated frequency offset. 
     A fifth embodiment of the disclosure considers a frequency offset determination based on correlations of symbols in a PUCCH transmission conveying HARQ-ACK information. 
     The eNB  102  receiver can determine an estimate of a frequency offset (cumulative frequency offset due to frequency offsets at UE  114  transmitter and eNB  102  receiver) based on symbol-by-symbol time-domain or frequency-domain correlations across SCs that include DMRS symbols or both DMRS symbols and HARQ-ACK symbols. 
     In a first approach, considering the PUCCH SF structure in  FIG. 7  or  FIG. 11  and that UE  114  does not apply slot-based FH for a PUCCH transmission, the eNB  102  receiver combines, for example by averaging, the three received DMRS symbols in a first slot of a SF to obtain a first combined received DMRS symbol  p   0  and the three received DMRS symbols in a second slot of the SF to obtain a second combined received DMRS symbol  p   1 . Due to combining, an SINR of  p   0  or  p   1  is 10 log 10 (3)=4.77 dB larger than a SINR of individual DMRS symbols thereby allowing for improved estimation of a frequency offset based on a correlation ρ= p   0 · p*   1 . A frequency offset can be computed as {circumflex over (f)} offset =∠ρ/(2π·T 0′ ) where T 0 =0.5e−3 seconds. Equivalently, denoting by p 0 (j) the DMRS symbols in the first slot of the SF and by p 1 (j) the DMRS symbols in the second slot of the SF, where j=0, 1, 2, the correlation can be obtained as 
             ρ   =       1   3     ·       ∑     j   =   0     2     ⁢           ⁢         p   0     ⁡     (   j   )       ·       p   1   *     ⁡     (   j   )                   
where the scaling by ⅓ is optional as it does not affect a phase in the correlation value.
 
     In a second approach, considering the PUCCH SF structure in  FIG. 7  or  FIG. 11  and that UE  114  does not apply slot-based FH for a PUCCH transmission with repetitions and considering that identical information is transmitted in a SF symbol with a same index in each of the two slots of the SF when a scrambling sequence remains same per SF slot, an eNB  102  receiver can correlate, across SC, symbols with same indexes in each slot to obtain an estimate of a frequency offset for receptions from UE  114 . Denoting by c 0 (j) the symbols across SCs in a first slot of a PUCCH SF and by c 1 (j) the symbols across SCs in a second slot of the PUCCH SF, where for example j=0, . . . , 6, a correlation can be obtained as 
             ρ   =       1   7     ·       ∑     j   =   0     6     ⁢           ⁢         c   0     ⁡     (   j   )       ·         c   1   *     ⁡     (   j   )       .                 
Similar to modulated data symbols in the fourth embodiment, the eNB  102  receiver does not need to know a value for the HARQ-ACK information in order to perform a correlation since the value is same in different PUCCH symbols (other than PUCCH symbols used for DMRS transmission). A frequency offset estimate can be computed as {circumflex over (f)} offset =∠ρ/(2π·T 0′ ) where T 0 =0.5e−3 seconds.
 
       FIG. 18  illustrates an example frequency offset estimation based on correlations across SCs of both DMRS symbols and HARQ-ACK information symbols in a PUCCH transmission over one SF according to this disclosure. 
     UE  114  transmits a PUCCH over a SF that includes a first slot  1802  and a second slot  1804 . A transmission in the first slot and in the second slot is over a same RB of an UL system BW. The eNB  102  receives the PUCCH and performs a symbol by symbol correlation among symbols across SCs in the first slot and symbols in the second slot (assuming use of a same scrambling sequence per slot) to obtain J=7 individual correlations. The first slot includes symbols c 0 (0)  1810 , c 0 (1)  1811 , c 0 (5)  1815  and c 0 (6)  1816  that convey HARQ-ACK symbols and symbols c 0 (2)  1812 , c 0 (3)  1813  and c 0 (4)  1814  that convey DMRS symbols. The second slot includes symbols c 1 (0)  1820 , c 0 (1)  1821 , c 1 (5)  1825  and c 1 (6)  1826  that convey HARQ-ACK information and symbols c 1 (2)  1822 , c 1 (3)  1823  and c 1 (4)  1824  that convey DMRS symbols. UE  114  transmits same HARQ-ACK information and same DMRS in every respective symbol in the first slot and the second slot. The eNB  102  receiver computes a sum of correlations 
             ρ   =       1   7     ·       ∑     j   =   0     6     ⁢           ⁢         c   0     ⁡     (   j   )       ·       c   1   *     ⁡     (   j   )                   
(scaling by 1/7 is optional for the purpose of obtaining a phase of ρ) and a frequency offset estimate {circumflex over (f)} offset  can be obtained as {circumflex over (f)} offset =∠ρ/(2π·T 0′ ) where T 0 =0.5e−3 seconds. Frequency offset correction based on a PUCCH reception can also be based on repetitions over subframes (instead of slots) in a same manner as for frequency offset correction based on a PUSCH reception.
 
     A sixth embodiment of the disclosure considers eNB  102  adjusting a number of repetitions for an UL transmission from UE  114  before and after a frequency offset correction. 
     The eNB  102  can adjust a number of repetitions for an UL transmission from UE  114  depending on whether or not eNB  102  corrects a frequency offset for transmissions from UE  114 . Similar, the eNB  102  can adjust a number of repetitions for a DL transmission to UE  114  depending on whether or not eNB  102  determines that UE  114  corrects a frequency offset for transmissions from eNB  102 . This is because prior to an estimation and correction of a frequency offset that can be above 100 Hz, eNB  102  cannot assume that eNB  102  (or UE  114 ) can perform inter-SF DMRS filtering in order to improve an accuracy of a channel estimate that eNB  102  (or UE  114 ) uses to perform coherent demodulation of modulated symbols conveying data information. Without, or with limited, inter-SF DMRS filtering, an accuracy of the channel estimate can become a limiting factor in achieving a target data reception reliability. 
     The eNB  102  can address an inability to improve an accuracy of a channel estimate prior to correcting a frequency offset, due to a respective inability to perform inter-SF DMRS filtering, by configuring a larger number of repetitions for an UL channel transmission from UE  114  (or for a DL channel transmission to UE  114 ) than after correcting the frequency offset. For example, eNB  102  needs to correct a frequency offset of UL transmissions from UE  114  when UE  114  establishes initial communication with eNB  102  or, more typically, when UE  114  exits from an extended discontinuous reception state where UE  114  can experience a local oscillator drift. Similar, UE  114  needs to correct a frequency offset of DL transmissions from eNB  102  when UE  114  establishes communication with eNB  102  and UE  114  can also use a transmission with repetitions from eNB  102 , such as a PBCH transmission, to correct a frequency offset using symbol replicas in repetitions of a DL channel transmission, such as a PBCH transmission, as it was previously described for example with respect to repetitions of a PUSCH transmission. 
     In such cases, and for otherwise identical transmitter, receiver, or channel conditions, eNB  102  can configure a larger number of repetitions for a PUSCH transmission prior to correcting a frequency offset in order to ensure a target reception reliability and configure a smaller number of repetitions for a PUSCH transmission after correcting a frequency offset to account for improved reception reliability due to improved channel estimation accuracy that is enabled by inter-SF DMRS filtering. A configuration can be by higher layer signaling, such as RRC signaling, or by physical layer signaling in a physical DL control channel conveying an associated DL DCI format. 
       FIG. 19  illustrates a configuration by an eNB to a UE of a number of repetitions for a PUSCH transmission depending on whether or not the eNB corrects a frequency offset according to this disclosure. 
     The eNB  102  determines that UE  114  needs to transmit a PUSCH  1910 . For example, for initial access of UE  114  to eNB  102 , this determination can be for a PUSCH that UE  114  transmits as part of a random access process (see also REF 3 and REF 4). For example, this determination can be based on a positive SR or on a buffer status report that eNB  102  receives from UE  114 . The eNB  102  subsequently determines whether or not can assume a corrected frequency offset for transmissions from UE  114   1920 . For example, for initial access or for transmissions immediately after UE  114  exits a discontinuous reception state, eNB  102  can assume an uncorrected frequency offset while for transmissions after initial access or after a first transmission after UE  114  exits a discontinuous reception state, eNB  102  can previously correct a frequency offset. When eNB  102  does not assume a corrected frequency offset, eNB  102  configures to UE  114  a first number of repetitions for a PUSCH transmission  1930  that conveys a data TB size using a set of transmission parameters such as a PRB allocation and a modulation and coding scheme. When eNB  102  assumes a corrected frequency offset, eNB  102  configures to UE  114  a second number of repetitions for a PUSCH transmission  1940  for a same data TB size and for a same set of transmission parameters. 
     Alternatively, eNB  102  can buffer receptions of repetitions for a PUSCH transmission, possibly after some further processing such as combining, estimate and correct a frequency offset, for example as described in previous embodiments, and subsequently perform demodulation and decoding of modulated data symbols in the buffered receptions of repetitions for the PUSCH transmission. 
     To aid the Patent Office and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants wish to note that they do not intend any of the appended claims or claim elements to invoke 35 U.S.C. § 112(f) unless the words “means for” or “step for” are explicitly used in the particular claim. Use of any other term, including without limitation “mechanism,” “module,” “device,” “unit,” “component,” “element,” “member,” “apparatus,” “machine,” “system,” “processor,” or “controller,” within a claim is understood by the applicants to refer to structures known to those skilled in the relevant art and is not intended to invoke 35 U.S.C. § 112(f). 
     Although the present disclosure has been described with example embodiments, various changes and modifications can be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications that fall within the scope of the appended claims.