PATENT DOCUMENT

Publication Number: US-11469806-B2
Application Number: US-201816133208-A
Country: US
Kind Code: B2

Title: CSI measurement and feedback for eMTC-U system

Abstract:
Techniques described herein can facilitate Channel-State Information (CSI) measurement and feedback for communication in unlicensed spectrum or Sounding Reference Signal (SRS) transmission and/or channel-state estimation for communication in unlicensed spectrum. In an example, an apparatus is configured to be employed in a User Equipment (UE), and the apparatus comprises a Radio Frequency (RF) circuitry interface and processing circuitry configured to perform CSI measurement for communication in unlicensed spectrum. The apparatus further generates data for feedback according to the CSI measurement, and sends the data for feedback to RF circuitry via the RF circuitry interface. In an example, a frame structure of a data channel begins with a downlink (DL) transmission or soon after an initial signal. In an example, the CSI measurement includes measuring Channel Quality Information (CQI) for one or more sub-bands.

Claims:
What is claimed is: 
     
       1. A User Equipment (UE), comprising:
 a Radio Frequency (RF) circuitry interface; and 
 processing circuitry, configured to:
 perform a Channel-State Information (CSI) measurement for communication in an unlicensed spectrum; 
 generate data for feedback according to the CSI measurement; and 
 send the data for feedback to RF circuitry via the RF circuitry interface, 
 
 wherein a frame structure of a data channel for the communication begins with a frequency tuning period, followed by a presence signal period, followed by a downlink (DL) transmission, wherein the frame structure is a DL-uplink (UL)-DL-UL frame structure; and 
 wherein the CSI measurement includes a Channel Quality Information (CQI) for a sub-band. 
 
     
     
       2. The UE of  claim 1 , wherein a total band for the communication is divided into multiple sub-bands, and wherein the processing circuitry is further configured to measure the CQI for each sub-band. 
     
     
       3. The UE of  claim 1 , wherein the processing circuitry is further configured to generate data for a hopping sequence for the communication in a pseudo random manner, and wherein a constraint is added to limit a separation in frequency among two adjacent channels. 
     
     
       4. The UE of  claim 1 , wherein the DL-UL-DL-UL frame structure further includes a Clear Channel Assignment (CCA) and enhanced CCA (eCCA) period, the presence signal period, a DL subframes period, a UL subframes period, a CCA and eCCA period, a DL subframes period and a UL subframes period in sequence. 
     
     
       5. The UE of  claim 1 , wherein the processing circuitry is further configured to: perform long term measurement of the CQI on a specific sub-band based on continuous DL transmissions over the specific sub-band; and generate data for periodic feedback with a periodicity as for reporting mode 1-0, where the periodicity is to be configured through Radio Resource Control (RRC) or Downlink Control Information (DCI) signaling. 
     
     
       6. The UE of  claim 1 , wherein the processing circuitry is further configured to generate the CQI for all sub-bands or only the CQI related to a specific sub-band periodically. 
     
     
       7. The UE of  claim 1 , wherein a number of sub-bands is fixed or predefined or is flexibly changed through higher layer signaling. 
     
     
       8. The UE of  claim 7 , wherein periodic reporting mode 3-0 or 3-1 is to be reused, or periodic mode 2-0 and/or 2-1 is to be used where the number of sub-bands are selected based on a list. 
     
     
       9. The UE of  claim 1 , wherein the processing circuitry is further configured to compute the CQI based on a measurement of a previous DL transmission occurred over an adjacent channel in a previous hop. 
     
     
       10. The UE of  claim 1 , wherein active channels for the communication having high correlation are to be chosen by a base station. 
     
     
       11. The UE of  claim 1 , wherein the CQI is reported as a wideband CQI. 
     
     
       12. The UE of  claim 1 , wherein the CQI includes a wideband CQI and a sub-band CQI, and the sub-band CQI is 2 bit differential field based on the wideband CQI. 
     
     
       13. The UE of  claim 1 , wherein the processing circuitry is configured to compute the CQI as follows:
 a total bandwidth constructed by channels in a list; 
 a total bandwidth of multiple adjacent channels; and 
 a total bandwidth of a specific channel. 
 
     
     
       14. The UE of  claim 1 , wherein the processing circuitry is further configured to evaluate the CQI according to a UE preferred channel index or Resource Blocks (RBs). 
     
     
       15. The UE of  claim 1 , wherein the processing circuitry is further configured to evaluate the sub-band CQI as follows:
 the CQI based on one specific channel; and 
 the CQI on selected RBs within the one specific channel. 
 
     
     
       16. The UE of  claim 1 , wherein the CQI is reported aperiodically. 
     
     
       17. The UE of  claim 1 , wherein the communication is an enhanced Machine Type Communication (eMTC). 
     
     
       18. One or more non-transitory, computer-readable media comprising instructions that, when executed, cause an electronic device to:
 perform a Channel-State Information (CSI) measurement and feedback procedure for communication in an unlicensed spectrum, 
 wherein the CSI measurement and feedback procedure is over a frame structure of a data channel,
 wherein the frame structure is a downlink-uplink (DL-UL) frame structure including a frequency tuning period, a CCA and eCCA period, a presence signal period, followed by a DL subframes period and a UL subframes period in sequence, 
 wherein a total band for the communication is divided into multiple sub-bands, and wherein the processing circuitry is further configured to measure a Channel Quality Information (CQI) for each sub-band.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/559,239 filed Sep. 15, 2017, entitled “CHANNEL STATE INFORMATION MEASUREMENT AND FEEDBACK FOR ENHANCED MACHINE-TYPE COMMUNICATIONS IN UNLICENSED MEDIUM”, U.S. Provisional Application No. 62/576,524 filed Oct. 24, 2017, entitled “SOUNDING REFERENCE SIGNAL (SRS) TRANSMISSIONS AND CHANNEL-STATE ESTIMATE FOR ENHANCED MACHINE TYPE COMMUNICATION SYSTEMS OPERATION IN UNLICENSED SPECTRUM (EMTC-U)”, U.S. Provisional Application No. 62/584,633 filed Nov. 10, 2017, entitled “CHANNEL STATE INFORMATION MEASUREMENT AND FEEDBACK FOR ENHANCED MACHINE-TYPE COMMUNICATIONS IN UNLICENSED MEDIUM”, and U.S. Provisional Application No. 62/595,888 filed Dec. 7, 2017, entitled “CHANNEL STATE INFORMATION MEASUREMENT AND FEEDBACK FOR ENHANCED MACHINE-TYPE COMMUNICATIONS IN UNLICENSED MEDIUM”, the contents of which are herein incorporated by reference in their entirety. 
    
    
     FIELD 
     The present disclosure relates to the field of wireless communications, and more specifically, to Channel State Information (CSI) measurement and feedback for communication in unlicensed spectrum or to Sounding Reference Signal (SRS) transmission and/or channel-state estimation for communication in unlicensed spectrum. 
     BACKGROUND 
     Internet of Things (IoT) is envisioned as a significantly important technology component, which has huge potential, and may change our daily life entirely by enabling connectivity between tons of devices. IoT has wide applications in various scenarios, including smart cities, smart environment, smart agriculture, and smart health systems. 
     3GPP has standardized two designs to support IoT services—enhanced Machine Type Communication (eMTC) and NarrowBand IoT (NB-IoT). As eMTC and NB-IoT, User Equipments (UEs) may be deployed in huge numbers, lowering the cost of these UEs is a key enabler for implementation of IoT. Also, low power consumption is desirable to extend the life time of the battery. In addition, there are substantial use cases of devices deployed deep inside buildings, in which coverage enhancement is desired in comparison to the defined LTE cell coverage footprint. In summary, eMTC, and NB-IoT techniques are designed to ensure that the UEs have low cost, low power consumption, and enhanced coverage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like elements. Embodiments are illustrated by way of examples and not by way of limitation in the figures of the accompanying drawings. 
         FIG. 1  illustrates an exemplary frame structure in accordance with some embodiments of the present disclosure. 
         FIG. 2  illustrates an example of bandwidth partition over four sub-bands in accordance with some embodiments of the present disclosure. 
         FIG. 3  illustrates an exemplary frame structure in accordance with some embodiments of the present disclosure. 
         FIG. 4  illustrates an exemplary frame structure in accordance with some embodiments of the present disclosure. 
         FIG. 5  illustrates an example of bandwidth partition over four sub-bands in accordance with some embodiments of the present disclosure. 
         FIG. 6  illustrates an exemplary electronic apparatus or system in accordance with some embodiments of the present disclosure. 
         FIG. 7  illustrates an exemplary electronic apparatus or system in accordance with some embodiments of the present disclosure. 
         FIG. 8  is a flow chart illustrating an exemplary procedure in accordance with some embodiments of the present disclosure. 
         FIG. 9  is a flow chart illustrating an exemplary procedure in accordance with some embodiments of the present disclosure. 
         FIG. 10  illustrates an architecture of a system of a network in accordance with some embodiments of the present disclosure. 
         FIG. 11  illustrates an architecture of a system of a network in accordance with some embodiments of the present disclosure 
         FIG. 12  illustrates exemplary components of a device in accordance with some embodiments of the present disclosure. 
         FIG. 13  illustrates exemplary interfaces of baseband circuitry in accordance with some embodiments of the present disclosure. 
         FIG. 14  is an illustration of a control plane protocol stack in accordance with some embodiments of the present disclosure. 
         FIG. 15  is an illustration of a user plane protocol stack in accordance with some embodiments of the present disclosure. 
         FIG. 16  illustrates components of a core network in accordance with some embodiments of the present disclosure. 
         FIG. 17  is a block diagram illustrating components in accordance with some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description refers to the accompanying drawings. The same reference numbers may be used in different drawings to identify the same or similar elements. In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular structures, architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the various aspects of various embodiments. However, it will be apparent to those skilled in the art having the benefit of the present disclosure that the various aspects of the various embodiments may be practiced in other examples that depart from these specific details. In certain instances, descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the various embodiments with unnecessary detail. For the purposes of the present document, the phrase “A or B” means (A), (B), or (A and B). In an aspect, embodiments of the present disclosure are related to Long Term Evolution (LTE) operation in unlicensed spectrum in MulteFire, specifically the Internet of Things (IoT) operating in unlicensed spectrum. In an aspect, embodiments of the present disclosure are related to communication in unlicensed spectrum, more specifically, enhanced Machine Type Communication (eMTC) in unlicensed spectrum. In an aspect, embodiments of the present disclosure are related to CSI measurement and feedback for communication in unlicensed spectrum. In an aspect, embodiments of the present disclosure are related to the SRS transmission and/or channel-state estimation for communication in unlicensed spectrum. 
     Both release (Rel)-13 eMTC and NB-IoT operates in licensed spectrum. On the other hand, the scarcity of licensed spectrum in low frequency band results in a deficit in the data rate boost. Thus, there are emerging interests in the operation of LTE systems in unlicensed spectrum. 
     Potential LTE operation in unlicensed spectrum includes, but is not limited to the Carrier Aggregation based on Licensed Assisted Access (LAA)/enhanced LAA (eLAA) systems, LTE operation in the unlicensed spectrum via Dual Connectivity (DC), and the standalone LTE system in the unlicensed spectrum, where LTE-based technology solely operates in unlicensed spectrum without requiring an “anchor” in licensed spectrum—called MulteFire. 
     To extend the benefits of LTE IoT designs into unlicensed spectrum, MulteFire 1.1 is expected to specify the design for Unlicensed-IoT (U-IoT). The embodiments herein as discussed with respect to U-IoT systems, with focus on the eMTC based U-IoT design. Note that similar approaches can be used to NB-IoT based U-IoT design as well, and the embodiments herein may be applicable to other systems, such as fifth generation (5G) New Radio (NR) systems. 
     The unlicensed frequency band of interest for various embodiments is the 2.4 GHz band. For global availability, the design should abide by the regulations in different regions, e.g., the regulations given by FCC in US and the regulations given by ETSI in Europe. Based on these regulations, frequency hopping is more appropriate than other forms of modulations, due to more relaxed Power Spectrum Density (PSD) limitation and co-existence with other unlicensed band technology such as Bluetooth and WiFi. Specifically, frequency hopping has no PSD limit while other wide band modulations have PSD limit of 10 dBm/MHz in regulations given by ETSI. The low PSD limit would result in limited coverage. Embodiments herein include U-IoT with frequency hopping. 
     Since in unlicensed eMTC (eMTC-U) (i.e., eMTC in unlicensed spectrum) the data channel hops from one channel to another, and the hopping sequence depends on whether or not the carrier sensing procedure succeeds over the available channels, the CSI measurement and feedback between downlink (DL) and uplink (UL) represents an issue, and the LTE-legacy methodology cannot be reused as is. Therefore, embodiments herein include mechanisms to efficiently perform CSI measurement and feedback in eMTC-U systems. 
     In LTE, support for downlink channel-dependent scheduling includes the Channel-State Information (CSI), which is provided by the UEs to the network and contains information about the current channel conditions. The exact content of the CSI report depends on both the reporting mode the UE is configured to be in, and the Transmission Mode (TM 1-10). Cell-specific Reference-Signals (CRS) are used to acquire CSI in TM 1-8, while CSI Reference Signals (CSI-RS) are intended to be used by the UEs to acquire CSI in TM 9 and 10. In LTE there are two types of CSI report: aperiodic, where the reports are transmitted on the Physical Uplink Shared Channel (PUSCH) upon request by the network, and periodic, where the reports are transmitted periodically on the Physical Uplink Control Channel (PUCCH), and are generally quite long implying that the information in a report may not be possible to be transmitted in a single sub-frame. 
     In legacy LTE, the aperiodic reporting supports three modes:
         a. The wideband reports are short reports, which reflect the average channel quality across the entire cell bandwidth with a single Channel Quality Information (CQI) value, while the Precoder Matrix Indicator (PMI) reporting might be frequency selective.   b. For the UE-selected reports the UE provides in addition to a wideband CQI value as the wideband report, another value which reflects the best M sub-bands over which the BW is divided into. This type of report thus provides frequency-domain information about the channel conditions.   c. For the configured reports the UE reports one wideband CQI reflecting the channel quality across the full downlink carrier bandwidth and one CQI per sub-band, over which the BW is divided into. Similarly to the UE-selected reports, depending on the sub-mode configured, the PMI and Rank Indicator (RI) are also provided as part of this type of report.       

     As for periodic reporting, LTE legacy supports two modes:
         a. The wideband reports, which works in the same manner as for aperiodic report;   b. For the UE-selected reports, the total bandwidth is divided into four bandwidth parts. The wideband CQI and PMI (if enabled) are reported together with a cyclic info of the best-band and CQI for that band.       

     As for legacy eMTC, only the following transmission modes are supported: TM1, TM2, TM6 (for CRS-based transmission schemes), and TM9 (for DM-RS-based transmission schemes). Furthermore, in order to simplify the CSI measurements and feedback, PMI/RI report is not applicable to TM9 (no support for x-1 and x-2 reporting mode). In legacy eMTC, CSI measurement and feedback is only supported in CE mode A. In CE mode A, the following reporting mode are supported: 
     For aperiodic reports only mode 2-0 is supported for all transmission modes available. For periodic reports mode 1-0 is supported for TM1, TM2 and TM9 and mode 1-1 is supported for TM 6 and TM 9. 
     In eMTC, both sub-band and wideband CSI are supported, where the sub-band CQI size is 6 Physical Resource Blocks (PRBs). In both legacy LTE and eMTC, since the transmissions are performed over the same licensed band, the evaluation of the CQI is performed by estimating the channel quality through the downlink CRS or CSI-RS (SCI-RS), which are transmitted in the previous DL transmissions. 
     In eMTC-U, one of the main constraint for the CSI measurement and feedback is that the data channel hops from one channel to another, and furthermore the transmission on a specific data channel relies on the success of the carrier sensing procedure over that channel. This means that the measurement done over a channel are not valid on another, and if the Clear Channel Assignment (CCA) fails over a specific channel the system may hop over that channel after a minimum time of 1.2 s (15×80 ms), which makes the measurement and eventually the feedback reported on that channel outdated. For this reason, a different data frame structure and the modality for the measurement and feedback of the CSI report may be introduced for the unlicensed eMTC in embodiments of the present disclosure. 
     In an embodiment, the frame structure of the data channel begins with a downlink transmission, or soon after an initial signal, which is used for reliable presence detection of the data channel on which the system has hopped to. This is done to feed CSI measurements (e.g., CQI) to the UEs over that specific channel. 
     An exemplary frame structure  100  according to some embodiments is illustrated in  FIG. 1 . In an embodiment, an UE  101  (e.g., the UE  1001  or  1002  discussed in accordance with  FIG. 10 , which will be discussed later) and an evolved NodeB (eNB)  102  (e.g., the node  1011  or  1012  discussed in accordance with  FIG. 10 , which will be discussed later) may communicate over the frame structure  100 . In an embodiment, under this scheduled report modality, the frame structure  100  is composed by a sequence DL-UL-DL-UL. In this case, the uplink transmission cannot be fully used for CSI feedback, since the eNB  102  is to first grant request for CSI through the uplink grant scheduling, such that the report sent from the UE  101  and/or other UEs may not be wasted. This implies some processing and scheduling delays, which preclude some subframes (SFs) to be used. In an embodiment, additional CCA overhead is introduced, since the channel sensing is to be performed again after the first UL transmission. 
     According to some embodiments, the frame structure  100  includes DL SFs  111 , UL SFs  112 , DL SFs  113  and UL SFs  114 . Furthermore, the frame structure  100  may include a frequency tuning period  121 , a CCA and enhanced CCA (eCCA) period  122 , a presence signal period  123  and a CCA and eCCA period  124 . As illustrated in  FIG. 1 , the sequence of the frame structure  100  may be in the sequence of the frequency tuning period  121 , the CCA and eCCA period  122 , the presence signal period  123 , DL SFs  111 , the UL SFs  112 , the CCA and eCCA period  124 , DL SFs  113  and UL SFs  114 . In an embodiment, the dwelling time of the frame structure  100  may be several tens of milliseconds. In an embodiment, the dwelling time of the frame structure  100  may be approximately 75 milliseconds. 
     In an embodiment, the total band over which the system hops in is divided over multiple sub-bands. In an embodiment, the CQI is measured over each single sub-band, and the number of sub-bands, in which the total band is divided, and this defines the granularity of the CQI measurement (with maximum granularity being the hopping channel). An example of bandwidth partition over four sub-bands is illustrated in  FIG. 2  with a granularity of four sub-bands. As illustrated in  FIG. 2 , the CQI for four sub-bands (i.e., CQI  201 , CQI  202 , CQI  203  and CQI  204 ) are measured. In an embodiment, the CQI for all sub-bands is periodically transmitted. In other embodiments, only the CQI related to a specific sub-band is transmitted. 
     The number of sub-bands, may be fixed or predefined, or it may be flexibly changed through higher layer signaling. Alternatively, the bandwidth of sub-band is configured by the eNB  102  or pre-defined. 
     An exemplary frame structure  300  according to some embodiments is illustrated in  FIG. 3 . In an embodiment, an UE  301  (e.g., the UE  1001  or  1002  discussed in accordance with  FIG. 10 , which will be discussed later) and an eNB  302  (e.g., the node  1011  or  1012  discussed in accordance with  FIG. 10 , which will be discussed later) may communicate over the frame structure  300 . In an embodiment, the UE  301  performs long term measurement of the CQI on a specific sub-band based on continue DL transmissions over that sub-band. In an embodiment, the UE  301  provides periodic feedback as for LTE legacy reporting mode 1-0, where the periodicity may be configured through RRC or Downlink Control Information (DCI) signaling. In an embodiment, periodic reporting mode 3-0 or 3-1 may be reused. In an embodiment, periodic mode 2-0 and/or 2-1 may be used where the M sub-bands are selected based on a whitelist. 
     According to some embodiments, the frame structure  300  is a DL-UL frame structure including DL SFs  311  and UL SFs  312 . Furthermore, the frame structure  300  may include a frequency tuning period  321 , a CCA and eCCA period  322  and a presence signal period  323 . As illustrated in  FIG. 3 , the sequence of the frame structure  300  may be in the sequence of the frequency tuning period  321 , the CCA and eCCA period  322 , the presence signal period  323 , DL SFs  311  and the UL SFs  312 . In an embodiment, the dwelling time of the frame structure  300  may be several tens of milliseconds. In an embodiment, the dwelling time of the frame structure  300  may be approximately 75 milliseconds. 
     In an embodiment, the hopping sequence is still generated in a pseudo random manner in order to comply with the regulation, but an additional constraint is added to limit the separation in frequency among two adjacent channels. This is done with the aim to guarantee that the channels used by two consequent frequency hops are sufficiently close. In an embodiment, the generation of the sequence is done such a way that next hop is correlated with the previously hop, and a new hop is limited to a certain range of values based upon the previous hop (limiting the maximum distance from it). In an embodiment, if such approach is adopted, a frame structure with sequence DL-UL (e.g., the frame structure  300 ) may be used, and the CQI report may be computed based on the measurement of the previous DL transmission occurred over the adjacent channel in the previous hop. In an embodiment, the CQI report may be done in a periodic manner following LTE legacy mode 1-0. In other embodiments, when choosing the active channels, the eNB  102  or  302  may try to choose the channel having high correlation. 
     In an embodiment, the Rank Indicator (RI) is not reported, and the rank is fixed to 1. In an embodiment, only CQI is reported and mode x-2 and x-3 are not supported. 
     In an embodiment, one or two extra bits may be added in the related DCI to indicate if at a given time one or the others is used. 
     In an embodiment, a periodic reporting is performed. In an embodiment, the CQI report may be done as a wideband CQI. In an embodiment, as a complement or in alternative, the UE  101  or  301  selects preferred channel indexes, or Resource Blocks (RBs). In an embodiment, as a complement or in alternative, the total bandwidth is divided into sub-bands, and the sub-band CQI may be 2 bit differential field based on wideband CQI. 
     In an embodiment, as legacy eMTC only mode 1-0 and 1-1 are supported, where the latest contains a wideband CQI (4 bits long) and a wideband PMI (2 bits). In an embodiment, for wideband CQI, this may be computed as follows:
         1. the total bandwidth constructed by the channels in a whitelist;   2. the total bandwidth of multiple adjacent channels, e.g., channels in a whitelist ranging from f C −f BW  to f C +f BW , where 2*f BW  is the coherent bandwidth. This may be configured by the eNB  102  or  302  or it may be pre-defined; and   3. the total bandwidth of a specific channel.       

     In an embodiment, frequency-selective CQI is supported. For instance, mode 2-0 or 3-0 is supported in conjunction with other modalities, e.g., mode 1-0 and/or mode 1-1. In an embodiment, the CQI is evaluated according to the UE  101  or  301  preferred channel index, or RBs. In this case, the index may be:
         1. The channel index within a whitelist; and   2. The index of N contiguous RBs within one specific channel, e.g., N=2 or 3.       

     In an embodiment, for sub-band CQI, this may be evaluated as follows:
         1. the CQI based on one specific channel; and   2. the CQI on selected RBs within one specific channel.       

     In an embodiment, mode 1-0 and 1-1 are supported, and each CQI and PMI is evaluated for each sub-band, as indicated above. In order to be able to fit the information related to the CQI and PMI for all the sub-bands, in which the total bandwidth is divided into, within the PUCCH (format 3) payload (21 bits total), one the two following options may be used: 
     1. The number of sub-bands is limited by the available bits within the PUCCH (format 3) payload that may be used for reporting CQI and PMI. The HARQ process IDs may be also properly fit within the PUCCH format 3, in order to reduce the payload. 
     2. In each PUCCH transmission, the PMI and CQI report information of only one sub-band at the time is included, which resembles what is done over PUCCH for feedback mode 2-0 in LTE-legacy. In other words, the reports for all the sub-bands are not sent together at the same time, but are spread over several reporting opportunities. In an embodiment, an offset between reports and an equation that indicates their periodic occurrence may be introduced, and it depends on the frame structure type over which the PUCCH transmission is performed. 
     In an embodiment, mode 2-1 and/or 3-1 is also supported. 
     In an embodiment, a scheduled CQI report transmission is supported, and aperiodic reporting is performed. In an embodiment, the CQI report may be done as a wideband CQI. In an embodiment, as a complement or in alternative, the UE  101  or  301  selects preferred channel indexes, or RBs. In an embodiment, as a complement or in alternative, the total bandwidth is divided into sub-bands, and the sub-band CQI may be 2 bit differential field based on wideband CQI. 
     In an embodiment, only mode 1-0 may be supported. In an embodiment, for wideband CQI, this may be computed as follows:
         1. the total bandwidth constructed by the channels in a whitelist;   2. the total bandwidth of multiple adjacent channels, e.g., channels in a whitelist ranging from f C −f BW  to f C +f BW , where 2*f BW  is the coherent bandwidth. This may be configured by the eNB  102  or  302  or it may be pre-defined;   3. the total bandwidth of a specific channel.       

     In an embodiment, only mode 1-1 is supported, which includes a wideband CQI, and a single PMI on this wideband CQI. In alternative, mode 1-1 is supported with other reporting modalities. 
     In an embodiment, only mode 2-0 is supported as the legacy eMTC systems or in conjunction with other modalities, e.g., mode 1-0 and/or mode 1-1. In an embodiment, the CQI is evaluated according to the UE  101  or  301  preferred channel index, or RBs. In this case, the index may be:
         1. The channel index within a whitelist;   2. The index of N contiguous RBs within one specific channel, e.g., N=2 or 3.       

     In an embodiment, for sub-band CQI, this may be evaluated as follows:
         1. The CQI based on one specific channel;   2. The CQI on selected RBs within one specific channel.       

     In an embodiment, similarly to legacy eMTC reporting mode 2-0, the following are included in the report: 
     1. the CQI/PMI evaluated per each sub-band; 
     2. CQI evaluated over a continuous set of RBs (i.e., one narrowband). In this last case, the CQI report may contain either the measurement over the current dwell or the measurement over the best narrow band. In an embodiment, this choice may be indicated through a bit field within the DCI. 
     In an embodiment, mode 2-1 is also supported. 
     In an embodiment, an offset may be contained within the DCI that triggers the CQI measurement:
         1 bit: “0” to indicate that the previous (or next) channel is to be used for CQI measurement; “1” to indicate that the current channel where the DCI is transmitted is to be used for CQI measurement. In alternative, “0” is used to indicate the previous (or next) channel, where DCI is transmitted, and “1” to indicate the next hopping channel.   2 bits: “00” to indicate that the previous channel is to be used for CQI measurement; “01” to indicate that the current channel, where the DCI is transmitted, is to be used for CQI measurement; “10” to indicate that the next channel is to be used for CQI measurement; and “11” is reserved.       

     More than 2 bits are used to indicate the channel index that is used for CQI measurement. 
     In an embodiment, the total band over which the system hops in is divided over multiple sub-bands as shown in  FIG. 2 , and described above. In one embodiment, the number of sub-bands may be explicitly set among a specific set of values (i.e., {1,2,3,4}) through RRC signaling (i.e., within the “cqi-ReportConfig” field) or it may depends on the cell bandwidth. In one embodiment, the sub-band size is fixed or high layer configured. In one embodiment, the number of sub-bands is related to the bandwidth available, and is equal to the total bandwidth divided by the sub-band size. In one embodiment, the number of sub-bands is fixed, and defined in the specification, or in alternative it may be semi-statically defined. In one embodiment, the center frequency of the sub-band is fixed or RRC signaled. 
     In an embodiment, the number of sub-bands is encoded in the bitmap, which provides an indication of the channel list given M groups and N channels (i.e., M=4, and N=14) to use: according to the bitmap info the number of sub-bands is known. In one embodiment, the adjacency of bits is an indication on the adjacency in the spectrum of the channels to use, and based on the bit separation the number of sub-bands may be defined. In one embodiment, one bit separation is sufficient for enabling an additional sub-band. For instance, given a bitmap composed by 14 bits, the following may be concluded:
         0 0 0 0 0 0 0 0 0 0 1 1 1 1→only one sub-band is used   0 0 0 1 1 0 0 0 0 0 0 0 1 1→two sub-bands are defined   0 0 0 0 0 0 0 1 0 1 0 1 0 1→four sub-bands are defined       

     In one embodiment, two or three or more bits of separation are the minimum threshold to configure an additional sub-band. The value of the bitmap itself provides also an indication of which channel belongs to which specific sub-band, based on how the channels are spaced between each other, and/or their position in the spectrum. 
     In one embodiment, the number of sub-bands is implicitly indicated by the channels that are enabled by the bitmap of the channel list, and the bandwidth separation among them. Additional sub-bands may be defined each time the separation between a channel and the others within the set of enabled channels is higher than X Khz, where X may be fixed, or higher layer configured. 
     In one embodiment, the bitmap signals the channels to be used in such a manner that this reflects how separated they are in frequency among each other based on the decimal representation of the bitmap, which we indicate here with S. For example, the bitmap may be organized such that a sequence of adjacent channels is indicated with low vales of S, while highly separated channels are indicated with higher values of S. According to this, brackets of values may be defined, such that according to the value of S, the number of sub-bands is known. As an example, if S&lt;=A the 1 sub-band is used, if B&lt;=S&lt;A 2 sub-bands are used, if C&lt;=S&lt;B 2 sub-bands are used, if D&lt;=S&lt;C 3 sub-bands are used, and if D&lt;S 4 sub-bands are used, where A&lt;B&lt;C&lt;D. 
     Since total number of hopping channel may be either 16 or 32, the number of hopping data channels within each sub-band may also calculated based on above embodiments. 
     In another embodiment, the hopping channels included in each sub-band is higher layer configured by the eNB  102  or  302 . For example, in “cqi-reportConfig”, the eNB  102  or  302  may explicitly configure number of sub-bands and the channels used in each sub-band using a bitmap. An example of this embodiment is provided below: 
     
       
         
           
               
             
               
                   
               
             
            
               
                 CQI-report-Subband-config-MF :: = SEQUENCE{ 
               
            
           
           
               
               
            
               
                 numberSub-band 
                 INTEGER {1, ... Max} 
               
               
                 sub-bandConfig 
                 { 
               
            
           
           
               
               
               
               
            
               
                   
                 subband1, 
                 Bit String (size (14)) 
                 OPTIONAL - Need on 
               
               
                   
                 subband2, 
                 Bit String (size (14)) 
                 OPTIONAL - Need on 
               
            
           
           
               
            
               
                 ... 
               
               
                 } 
               
               
                 } 
               
               
                   
               
            
           
         
       
     
     In an embodiment, the eNB  102  or  302  may configure maximum X sub-bands (where X is, e.g., 4). 
     Since in eMTC systems operation in unlicensed spectrum the data channel hops from one channel to another, and the hopping sequence depends on whether or not the carrier sensing procedure succeeds over the available channels, the SRS transmissions between UL and DL and the consequent channel-state estimation represent an issue, and the LTE-legacy methodology cannot be reused as is. Therefore, embodiments herein provide mechanisms to efficiently perform SRS transmissions in eMTC-U systems. 
     Embodiments herein provide mechanisms to perform Sounding Reference Signal (SRS) transmissions in eMTC-U systems, which are characterized by frequency hopping where the hopping sequence depends on the carrier sensing procedure success that effects the channel state estimation. The embodiments may support SRS transmission for channel-state estimation by the eNB to support uplink channel-dependent scheduling and link adaptation in eMTC-U systems. 
     In legacy-LTE, Sounding Reference Signals (SRSs) are intended to be used by the evolved NodeB (eNB) for channel-state estimation at different frequencies to support uplink channel-dependent scheduling and link adaptation, but also in other situations when uplink transmission is desired although there is no data to transmit, such as for uplink timing estimation as part of the uplink-timing-alignment procedure. Only one symbol may be reserved for SRS, which is the last symbol within a subframe (SF), even though in Time Division Duplexing (TDD) mode SRS may also be transmitted within the Uplink Pilot Time Slot (UpPTS). Similarly to Demodulation Reference Signal (DM-RS), a SRS is defined as a frequency-domain reference-signal sequence, which is a cyclic extension of prime-length Zadoff-Chu (ZC) sequence for sequence length bigger or equal to 30 or computer-generated sequence for sequence length less than 30, and it is cell-specific (typically, UE-specific reference signal sequences are not supported for SRS). An SRS is not necessarily transmitted together with any physical channel, and it may span over a different frequency range. Two types of SRS transmissions are defined in LTE: periodic and aperiodic SRS transmission. 
     Periodic SRS transmission may occur at regular time intervals (from as often as every 2 ms to as infrequently as 160 ms), and may be activated/deactivated through a one bit field called “SRS request” contained in the DCI format 0/0A/0B/4/4A/4B/1A/6-0A/6-1A for FDD mode, and DCI format 2B, 2C, 2D and 3B in TDD mode. Periodic SRS transmission spans on different frequency ranges and it allows two options: i) the SRS transmission is performed over a wideband of interest; ii) the SRS transmission occurs in a more narrowband fashion that is performed through the entire band of interest through hopping in frequency domain in such a way that a sequence of SRS transmissions jointly spans the frequency range of interest. The instantaneous SRS bandwidth is a multiple of four Resource Blocks, and the lengths of the reference-signal sequences for SRS are thus multiples of 24. Another characteristic of SRS is that the reference-signal is mapped in frequency domain every N subcarriers such that it creates different combs-like structures depending on the value of N. In order to multiplex different SRS transmissions, different cyclic-shifts may be applied to generate different SRSs that are orthogonal to each other. Another way to allow for SRS to be simultaneously transmitted from different UEs is to rely on the fact that each SRS only occupies every second (or every fourth) subcarrier. Thus, SRS transmissions from two devices may be frequency multiplexed by assigning them to different frequency shifts or “combs”. If a UE is transmitting SRS in a certain SF, the SRS transmission may overlap with PUSCH transmissions from other UEs within the cell. In order to avoid such collisions, UEs are aware of the set of SFs (which is provided as part of the cell system information) within which SRS is transmitted by any UE within the cell, and the UE avoid PUSCH transmission in the last Orthogonal Frequency-Division Multiplexing (OFDM) symbol of those SFs. As mentioned above, in this typology of transmission mode, many are the things that may be configured (e.g., periodicity, bandwidth, frequency hopping, comb type and number, etc.), that are here set through RRC signaling. 
     Aperiodic SRS transmissions are a one-shot transmission that is triggered by the “SRS request” field in the DCI form 0 used for uplink scheduling grant transmission. The SRS request field consists of two bits that are used to set one of the three preconfigured settings for the SRS transmissions (e.g., different configuration in terms of frequency position of the SRS transmission and/or the transmission comb), or dictate that no SRS should be transmitted. When such a trigger is received, a single SRS is transmitted in the next available aperiodic SRS instant configured for the UE using the configured frequency-domain parameters. Additional SRS transmissions may then be carried out if additional triggers are received. The frequency-domain structure of an aperiodic SRS transmission is identical to that of periodic SRS. Also, in the same way as for periodic SRS transmission, aperiodic SRS are transmitted within the last symbol of a subframe. Furthermore, the time instants when aperiodic SRS may be transmitted are configured per device using higher-layer signaling. 
     In eMTC-U, one of the main constraint for the SRS transmission is that the data channel hops from one channel to another. Furthermore, the transmission on a specific data channel relies on the success of the carrier sensing procedure over that channel. This means that the channel-state estimation done over a channel are not valid on another, and if the Clear Channel Assessment (CCA) fails over a specific channel the system will hop over that channel after a minimum time of 1.2 s (15×80 ms), which makes the estimate on that channel outdated. For this reason, the data frame structure and the modality for SRS transmission may be introduced for the eMTC-U systems in embodiments of the present disclosure. 
     In an embodiment, in eMTC-U, SRS signal is transmitted using 6 Resource Blocks (RBs) within a data hop. In an embodiment, the LTE-legacy structure and signal generation design may be reused. In an embodiment, the SRS signal may have a comb-like structure within the 6 RBs. In another embodiment, the SRS signal occupy all the tones across the 6 RBs, and different Cyclic Delay Diversity (CDD) or Orthogonal Cover Codes (OCCs) may be used for UE multiplexing. 
     In an embodiment, the SRS transmission is performed over the all 6 Physical Resource Blocks (PRBs). In an embodiment, the SRS transmission occurs in a PRB fashion that is performed through the entire 6 PRBs through hopping in frequency domain in such a way that a sequence of SRS transmissions jointly spans the frequency range of interest. In an embodiment, the SRS transmission hops may be carrier specific, not UE specific. In an embodiment, the hopping patterns follow the data hopping pattern, which is a function of Physical Cell Identity (PCI) and System Frame Number (SFN)+eFrame number. 
     In an embodiment, the periodic SRS transmission opportunities may be defined relative to the downlink (DL)/uplink (UL) configuration. For example, SRS transmission opportunity may be configured on the first UL SF within a data dwell. In case the DL/UL configuration changes in SIB-anchor, SRS may not be reconfigured. In an embodiment, once activated SRS transmission may not rely on DL CCA/enhanced CCA (eCCA) success or not. In an embodiment, the SRS opportunities are constrained to a specific data dwell, and even if a periodic SRS transmission is activated it is automatically disabled at the end of the available data dwell. 
     An exemplary frame structure  400  according to some embodiments is illustrated in  FIG. 4 . In an embodiment, an UE  401  (e.g., the UE  1001  or  1002  discussed in accordance with  FIG. 10 , which will be discussed later) and an eNB  402  (e.g., the node  1011  or  1012  discussed in accordance with  FIG. 10 , which will be discussed later) may communicate over the frame structure  400 . In an embodiment, the frame structure  400  of the data channel begins with a downlink transmission, or soon after an initial signal, which is used for reliable presence detection of the data channel on which the system has hopped to, and this is used to trigger periodic or aperiodic SRS transmissions within the available UL dwell time. In an embodiment, a DL-UL structure is adopted where the frame structure  400  is chosen. In this case, the uplink transmission cannot be fully used, since the eNB  402  is to first grant request for SRS transmission through the uplink grant scheduling or through DCI format 1/2A/2B/2C, such that the SRS transmission sent from the UE  401  and/or other UEs will not be wasted. This implies some processing and scheduling delays, which preclude some SFs to be used. In an embodiment, in order to extend the SRS transmissions opportunities, the frame structure comprises a sequence DL-UL-DL-UL, with the drawback that additional CCA overhead may be introduced, since the channel sensing is to be performed again after the first UL transmission. 
     According to some embodiments, the frame structure  400  includes DL SFs  411 , UL SFs  412 , DL SFs  413  and UL SFs  414 . Furthermore, the frame structure  400  may include a frequency tuning period  421 , a CCA and eCCA period  422 , a presence signal period  423  and a CCA and eCCA period  424 . As illustrated in  FIG. 4 , the sequence of the frame structure  400  may be in the sequence of the frequency tuning period  421 , the CCA and eCCA period  422 , the presence signal period  423 , DL SFs  411 , the UL SFs  412 , the CCA and eCCA period  424 , DL SFs  413  and UL SFs  414 . In an embodiment, the dwelling time of the frame structure  400  may be several tens of milliseconds. In an embodiment, the dwelling time of the frame structure  400  may be approximately 75 milliseconds. 
     In an embodiment, the total band over which the system hops in is divided over multiple sub-bands. In an embodiment, the channel state estimation is performed over each single sub-band, and the number of sub-bands, in which the total band is divided, defines the granularity of the channel state estimate (with maximum granularity being the hopping channel). An example of bandwidth partition over four sub-bands is illustrated in  FIG. 5  with a granularity of four sub-bands. As illustrated in  FIG. 5 , the CQI for four sub-bands (i.e., CQI  501 , CQI  502 , CQI  503  and CQI  504 ) are measured. In an embodiment, the SRS transmission is performed for all sub-bands in a periodical manner. In another embodiment, SRS transmissions are performed over a specific sub-band, which may be configured through higher layer signaling. In an embodiment, the sub-bands configuration for SRS may be the same or different as that of the sub-bands configuration of CSI-RS for downlink channel measurement. 
     In an embodiment, the number of sub-bands, may be fixed or predefined, or it may be flexibly changed through higher layer signaling. In an embodiment, similar consideration may be made on the number of time on which SRS transmissions are performed over a specific sub-band before, and the SRS is transmitted on a different band. In an alternative embodiment, the bandwidth of sub-band is configured by the eNB  402  or pre-defined. In one embodiment, the UE  401  performs periodic transmission of SRS where the periodicity can be configured through RRC. In such one embodiment, the eNB  402  performs long term channel state estimate on a specific sub-band based on continue SRS transmissions over that sub-band. In an embodiment, the SRS transmission for a sub-band is done by the means of a sufficiently wideband SRS transmission that allows for sounding of the entire frequency range of interest with a single SRS transmission. In an embodiment, the SRS transmission occurs over the means of a more narrowband transmission that is hopping in the frequency domain in such a way that a sequence of SRS transmission jointly spans the range of interest in a long run. 
     In an embodiment, the hopping sequence is still generated in a pseudo random manner in order to comply with the regulation, but an additional constraint is added to limit the separation in frequency among two adjacent channels. This is done with the aim to guarantee that the channels used by two consequent frequency hops are sufficiently close. In an embodiment, the generation of the sequence is done such a way that next hop is the most correlated with the previously hop. In an embodiment, correlation and channel separation can be jointly used for the sequence. In an embodiment, a frame structure with sequence DL-UL as well as the frame structure  400  with sequence DL-UL-DL-UL may be used, and long term channel state estimate is performed upon the channel-state estimate of the previous SRS transmission occurred over the adjacent channel in the previous hop. In an embodiment, the SRS transmission can be done in a periodic manner or in an aperiodic manner. 
     In an alternative embodiment, there is no SRS, and the eNB  402  may estimate the channel information based on the DM-RS of PUSCH. 
       FIG. 6  illustrates an exemplary electronic apparatus or system  600  configured to be employed in a UE (e.g., the UE  1001  or  1002  discussed in accordance with  FIG. 10 , which will be discussed later) or an IoT device that facilitates the CSI measurement and feedback or the SRS transmission and/or channel-state estimation for communication in unlicensed spectrum (e.g., eMTC-U) according to some embodiments. In an embodiment, the electronic system  600  comprises one or more processors  601  (e.g., the one or more processors discussed in accordance with  FIG. 12  and/or  FIG. 13 , which will be discussed later) configured to cause the UE to perform the CSI measurement and feedback for unlicensed eMTC or the SRS transmission and/or channel-state estimation for unlicensed eMTC as described above and herein. In an embodiment, the one or more processors  601  may include processing circuitry and an associated memory interface. In an embodiment, the electronic system  600  may further include a memory  602  coupled with the memory interface and communication circuitry  603  containing a transceiver or a transmitter and/or a receiver coupled to antenna(s). In an embodiment, the electronic system  600  may further include an RF circuitry interface to couple the processing circuitry to RF circuitry. 
       FIG. 7  illustrates an exemplary electronic apparatus or system  700  configured to be employed in an eNB (e.g., the node  1011  or  1012  discussed in accordance with  FIG. 10 , which will be discussed later) or IoT device that facilitates the corresponding CSI measurement and feedback or the SRS transmission and/or channel-state estimation for communication in unlicensed spectrum (e.g., eMTC-U) according to some embodiments. In an embodiment, the electronic system  700  comprises one or more processors  701  (e.g., the one or more processors discussed in accordance with  FIG. 12  and/or  FIG. 13 , which will be discussed later) configured to facilitate the CSI measurement and feedback for unlicensed eMTC or the SRS transmission and/or channel-state estimation for unlicensed eMTC as described above and herein. In an embodiment, the one or more processors  701  may include processing circuitry and an associated memory interface. In an embodiment, the electronic system  700  may further include a memory  702  coupled with the memory interface and communication circuitry  703  containing a transceiver or a transmitter and a receiver coupled to antenna(s). In an embodiment, the electronic system  700  may further include an RF circuitry interface to couple the processing circuitry to RF circuitry. 
       FIG. 8  is a flow chart illustrating an exemplary procedure  800  that facilitates the CSI measurement and feedback for communication in unlicensed spectrum (e.g., eMTC-U) according to some embodiments. At the operation  802 , processing circuitry of an electronic apparatus employed in a UE performs CSI measurement for communication in unlicensed spectrum. In an embodiment, the CSI measurement may include measuring CQI for one or more sub-bands. In an embodiment, the CSI measurement includes measuring CQI for each sub-band. In an embodiment, the processing circuitry of an electronic apparatus employed in a UE may perform the CQI measurement by performing long term measurement of the CQI on a specific sub-band based on continuous DL transmissions over that sub-band. In an embodiment, the processing circuitry may compute the CQI as follows: a total bandwidth constructed by the channels in a whitelist, a total bandwidth of multiple adjacent channels, and a total bandwidth of a specific channel. In an embodiment, the processing circuitry may further evaluate the CQI according to a UE preferred channel index or RBs. In an embodiment, the processing circuitry may further evaluate sub-band CQI as follows: the CQI based on one specific channel and the CQI on selected RBs within one specific channel. In one embodiment, the CQI may be wideband CQI. In an embodiment, the CQI may include wideband CQI and sub-band CQI. In such one embodiment, the sub-band CQI is 2 bit differential field based on the wideband CQI. 
     At the operation  804 , the processing circuitry of the electronic apparatus employed in the UE generates data for feedback according to the CSI measurement for the communication in unlicensed spectrum. At the operation  806 , the processing circuitry of the electronic apparatus employed in the UE sends the data for feedback for the communication in unlicensed spectrum to RF circuitry via an RF circuitry interface. In an embodiment, the feedback may be transmitted by the UE (e.g., to an eNB) periodically. In another embodiment, the feedback may be transmitted by the UE (e.g., to an eNB) aperiodically. In an embodiment, a frame structure of a data channel for the communication begins with a downlink (DL) transmission or soon after an initial signal. In one embodiment, the frame structure is a DL-UL-DL-UL frame structure. In such one embodiment, the DL-UL-DL-UL frame structure includes a frequency tuning period, a CCA and eCCA period, a presence signal period, a DL subframes period, a UL subframes period, a CCA and eCCA period, a DL subframes period and a UL subframes period in sequence. In one embodiment, the frame structure is a DL-UL frame structure. In such one embodiment, the DL-UL frame structure includes a frequency tuning period, a CCA and eCCA period, a presence signal period, a DL subframes period and a UL subframes period in sequence. In an embodiment, the procedure  800  may further include an optional operation that the processing circuitry of the electronic apparatus employed in the UE generates data for a hopping sequence for the communication in a pseudo random manner, and wherein a constraint is added to limit the separation in frequency among two adjacent channels. 
       FIG. 9  is a flow chart illustrating an exemplary procedure  900  that facilitates the SRS transmission and/or channel-state estimation for communication in unlicensed spectrum (e.g., eMTC-U) according to some embodiments. At the operation  902 , an SRS for UL channel estimation for communication in unlicensed spectrum is generated. In an embodiment, the communication is over a frame structure of the data dwell time comprises a DL dwell time and a UL dwell time, and a DL transmission in the DL dwell time is to trigger transmission of the SRS within an available UL dwell time. At the operation  904 , the SRS is transmitted in unlicensed spectrum (e.g., from a UE to an eNB). In one embodiment, SRS transmission hops for the SRS may be generated in a carrier-specific manner. In such one embodiment, hopping patterns for the SRS transmission hops may be generated based on a data hopping pattern. In such one embodiment, the data hopping pattern may be determined based on a function of a Physical Cell Identity (PCI) and System Frame Number (SFN)+eFrame number. In an embodiment, the frame structure comprises a DL-UL sequence or a DL-UL-DL-UL sequence. 
     In an alternative embodiment, the procedure  900  may further include an optional operation to detect a configuration via higher layer signaling, wherein the higher layer signaling comprises RRC signaling or NAS signaling, to determine or identify, based on the configuration, a number of sub-bands and/or a number of times on which SRS transmissions are to be performed over a specific sub-band before the SRS is transmitted on a different band, and to determine or identify a bandwidth of the sub-band based on the configuration. In an alternative embodiment, the procedure  900  may further include an optional operation to generate a hopping sequence such that channels have a specific separation in frequency among two adjacent channels and/or the channels are sufficiently correlated, wherein the SRS is to be communicated on a periodic basis or on an aperiodic basis. 
     In some embodiments, a computer-readable medium (e.g., a non-transitory computer-readable medium) comprises instructions, when executed (e.g., by one or more processors of the exemplary electronic system  600  or  700  and/or other electronic devices), to cause an electronic device to perform the exemplary procedures  800  or  900  and/or other procedures described above. 
     Embodiments described above and herein may be implemented into a system using any suitable hardware and/or software.  FIG. 10  illustrates an architecture of a system  1000  of a network in accordance with some embodiments. The system  1000  is shown to include a User Equipment (UE)  1001  and a UE  1002 . The UEs  1001  and  1002  are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks), but may also comprise any mobile or non-mobile computing device, such as Personal Data Assistants (PDAs), pagers, laptop computers, desktop computers, wireless handsets, or any computing device including a wireless communications interface. 
     In some embodiments, any of the UEs  1001  and  1002  can comprise an Internet of Things (IoT) UE, which can comprise a network access layer designed for low-power IoT applications utilizing short-lived UE connections. An IoT UE can utilize technologies such as Machine-to-Machine (M2M) or Machine-Type Communications (MTC) for exchanging data with an MTC server or device via a Public Land Mobile Network (PLMN), Proximity-Based Service (ProSe) or Device-to-Device (D2D) communication, sensor networks, or IoT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An IoT network describes interconnecting IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. The IoT UEs may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate the connections of the IoT network. 
     The UEs  1001  and  1002  may be configured to connect, e.g., communicatively couple, with a Radio Access Network (RAN)  1010 —the RAN  1010  may be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN (NG RAN), or some other type of RAN. The UEs  1001  and  1002  utilize connections  1003  and  1004 , respectively, each of which comprises a physical communications interface or layer (discussed in further detail below); in this example, the connections  1003  and  1004  are illustrated as an air interface to enable communicative coupling, and can be consistent with cellular communications protocols, such as a Global System for Mobile Communications (GSM) protocol, a Code-Division Multiple Access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a fifth generation (5G) protocol, a New Radio (NR) protocol, and the like. 
     In this embodiment, the UEs  1001  and  1002  may further directly exchange communication data via a ProSe interface  1005 . The ProSe interface  1005  may alternatively be referred to as a sidelink interface comprising one or more logical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Discovery Channel (PSDCH), and a Physical Sidelink Broadcast Channel (PSBCH). 
     The UE  1002  is shown to be configured to access an Access Point (AP)  1006  via connection  1007 . The connection  1007  can comprise a local wireless connection, such as a connection consistent with any IEEE 802.11 protocol, wherein the AP  1006  would comprise a wireless fidelity (WiFi®) router. In this example, the AP  1006  is shown to be connected to the Internet without connecting to the core network of the wireless system (described in further detail below). 
     The RAN  1010  can include one or more access nodes that enable the connections  1003  and  1004 . These Access Nodes (ANs) can be referred to as Base Stations (BSs), NodeBs, evolved NodeBs (eNBs), next Generation NodeBs (gNB), RAN nodes, and so forth, and can comprise ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). The RAN  1010  may include one or more RAN nodes for providing macrocells, e.g., macro RAN node  1011 , and one or more RAN nodes for providing femtocells or picocells (e.g., cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells), e.g., Low Power (LP) RAN node  1012 . 
     Any of the RAN nodes  1011  and  1012  can terminate the air interface protocol and can be the first point of contact for the UEs  1001  and  1002 . In some embodiments, any of the RAN nodes  1011  and  1012  can fulfill various logical functions for the RAN  1010  including, but not limited to, Radio Network Controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management. 
     In accordance with some embodiments, the UEs  1001  and  1002  can be configured to communicate using Orthogonal Frequency-Division Multiplexing (OFDM) communication signals with each other or with any of the RAN nodes  1011  and  1012  over a multicarrier communication channel in accordance various communication techniques, such as, but not limited to, an Orthogonal Frequency-Division Multiple Access (OFDMA) communication technique (e.g., for downlink communications) or a Single Carrier Frequency Division Multiple Access (SC-FDMA) communication technique (e.g., for uplink and ProSe or sidelink communications), although the scope of the embodiments is not limited in this respect. The OFDM signals can comprise a plurality of orthogonal subcarriers. 
     In some embodiments, a downlink resource grid can be used for downlink transmissions from any of the RAN nodes  1011  and  1012  to the UEs  1001  and  1002 , while uplink transmissions can utilize similar techniques. The grid can be a time-frequency grid, called a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot. Such a time-frequency plane representation is a common practice for OFDM systems, which makes it intuitive for radio resource allocation. Each column and each row of the resource grid corresponds to one OFDM symbol and one OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one slot in a radio frame. The smallest time-frequency unit in a resource grid is denoted as a resource element. Each resource grid comprises a number of resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block comprises a collection of resource elements; in the frequency domain, this may represent the smallest quantity of resources that currently can be allocated. There are several different physical downlink channels that are conveyed using such resource blocks. 
     The Physical Downlink Shared Channel (PDSCH) may carry user data and higher-layer signaling to the UEs  1001  and  1002 . The Physical Downlink Control Channel (PDCCH) may carry information about the transport format and resource allocations related to the PDSCH channel, among other things. It may also inform the UEs  1001  and  1002  about the transport format, resource allocation, and H-ARQ (Hybrid Automatic Repeat Request) information related to the uplink shared channel. Typically, downlink scheduling (assigning control and shared channel resource blocks to the UE  102  within a cell) may be performed at any of the RAN nodes  1011  and  1012  based on channel quality information fed back from any of the UEs  1001  and  1002 . The downlink resource assignment information may be sent on the PDCCH used for (e.g., assigned to) each of the UEs  1001  and  1002 . 
     The PDCCH may use Control Channel Elements (CCEs) to convey the control information. Before being mapped to resource elements, the PDCCH complex-valued symbols may first be organized into quadruplets, which may then be permuted using a sub-block interleaver for rate matching. Each PDCCH may be transmitted using one or more of these CCEs, where each CCE may correspond to nine sets of four physical resource elements known as Resource Element Groups (REGs). Four Quadrature Phase Shift Keying (QPSK) symbols may be mapped to each REG. The PDCCH can be transmitted using one or more CCEs, depending on the size of the Downlink Control Information (DCI) and the channel condition. There can be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation level, L=1, 2, 4, or 8). 
     Some embodiments may use concepts for resource allocation for control channel information that are an extension of the above-described concepts. For example, some embodiments may utilize an Enhanced Physical Downlink Control Channel (EPDCCH) that uses PDSCH resources for control information transmission. The EPDCCH may be transmitted using one or more Enhanced the Control Channel Elements (ECCEs). Similar to above, each ECCE may correspond to nine sets of four physical resource elements known as an Enhanced Resource Element Groups (EREGs). An ECCE may have other numbers of EREGs in some situations. 
     The RAN  1010  is shown to be communicatively coupled to a Core Network (CN)  1020 —via an S1 interface  1013 . In an embodiment, the CN  1020  may be an Evolved Packet Core (EPC) network, a NextGen Packet Core (NPC) network, or some other type of CN. In this embodiment, the S1 interface  1013  is split into two parts: the S1-U interface  1014 , which carries traffic data between the RAN nodes  1011  and  1012  and the Serving Gateway (S-GW)  1022 , and the S1-mobility Management Entity (MME) interface  1015 , which is a signaling interface between the RAN nodes  1011  and  1012  and MMEs  1021 . 
     In this embodiment, the CN  1020  comprises the MMEs  1021 , the S-GW  1022 , the Packet Data Network (PDN) Gateway (P-GW)  1023 , and a Home Subscriber Server (HSS)  1024 . The MMEs  1021  may be similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MMEs  1021  may manage mobility aspects in access such as gateway selection and tracking area list management. The HSS  1024  may comprise a database for network users, including subscription-related information to support the network entities&#39; handling of communication sessions. The CN  1020  may comprise one or several HSSs  1024 , depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS  1024  can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc. 
     The S-GW  1022  may terminate the S1 interface  1013  towards the RAN  1010 , and routes data packets between the RAN  1010  and the CN  1020 . In addition, the S-GW  1022  may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities may include lawful intercept, charging, and some policy enforcement. 
     The P-GW  1023  may terminate an SGi interface toward a PDN. The P-GW  1023  may route data packets between the EPC network  1023  and external networks such as a network including the application server  1030  (alternatively referred to as Application Function (AF)) via an Internet Protocol (IP) interface  1025 . Generally, the application server  1030  may be an element offering applications that use IP bearer resources with the core network (e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). In this embodiment, the P-GW  1023  is shown to be communicatively coupled to an application server  1030  via an IP communications interface  1025 . The application server  1030  can also be configured to support one or more communication services (e.g., Voice-over-Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs  1001  and  1002  via the CN  1020 . 
     The P-GW  1023  may further be a node for policy enforcement and charging data collection. Policy and Charging Enforcement Function (PCRF)  1026  is the policy and charging control element of the CN  1020 . In a non-roaming scenario, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with a UE&#39;s Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with local breakout of traffic, there may be two PCRFs associated with a UE&#39;s IP-CAN session: a Home PCRF (H-PCRF) within a HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF  1026  may be communicatively coupled to the application server  1030  via the P-GW  1023 . The application server  1030  may signal the PCRF  1026  to indicate a new service flow and select the appropriate Quality of Service (QoS) and charging parameters. The PCRF  1026  may provision this rule into a Policy and Charging Enforcement Function (PCEF) (not shown) with the appropriate Traffic Flow Template (TFT) and QoS Class of Identifier (QCI), which commences the QoS and charging as specified by the application server  1030 . 
       FIG. 11  illustrates an architecture of a system  1100  of a network in accordance with some embodiments. The system  1100  is shown to include a UE  1101 , which may be the same or similar to UEs  1001  and  1002  discussed previously; a RAN node  1111 , which may be the same or similar to RAN nodes  1011  and  1012  discussed previously; a User Plane Function (UPF)  1102 ; a Data network (DN)  1103 , which may be, for example, operator services, Internet access or 3rd party services; and a 5G Core Network (5GC or CN)  1120 . 
     The CN  1120  may include an Authentication Server Function (AUSF)  1122 ; a Core Access and Mobility Management Function (AMF)  1121 ; a Session Management Function (SMF)  1124 ; a Network Exposure Function (NEF)  1123 ; a Policy Control function (PCF)  1126 ; a Network Function (NF) Repository Function (NRF)  1125 ; a Unified Data Management (UDM)  1127 ; and an Application Function (AF)  1128 . The CN  1120  may also include other elements that are not shown, such as a Structured Data Storage network function (SDSF), an Unstructured Data Storage Network Function (UDSF), and the like. 
     The UPF  1102  may act as an anchor point for intra-RAT and inter-RAT mobility, an external PDU session point of interconnect to DN  1103 , and a branching point to support multi-homed PDU session. The UPF  1102  may also perform packet routing and forwarding, packet inspection, enforce user plane part of policy rules, lawfully intercept packets (UP collection); traffic usage reporting, perform QoS handling for user plane (e.g. packet filtering, gating, UL/DL rate enforcement), perform Uplink Traffic verification (e.g., SDF to QoS flow mapping), transport level packet marking in the uplink and downlink, and downlink packet buffering and downlink data notification triggering. UPF  1102  may include an uplink classifier to support routing traffic flows to a data network. The DN  1103  may represent various network operator services, Internet access, or third party services. NY  1103  may include, or be similar to application server  1030  discussed previously. 
     The AUSF  1122  may store data for authentication of UE  1101  and handle authentication related functionality. The AUSF  1122  may facilitate a common authentication framework for various access types. 
     The AMF  1121  may be responsible for registration management (e.g., for registering UE  1101 , etc.), connection management, reachability management, mobility management, and lawful interception of AMF-related events, and access authentication and authorization. AMF  1121  may provide transport for SM messages between and SMF  1124 , and act as a transparent proxy for routing SM messages. AMF  1121  may also provide transport for Short Message Service (SMS) messages between UE  1101  and an SMS function (SMSF) (not shown by  FIG. 11 ). AMF  1121  may act as Security Anchor Function (SEA), which may include interaction with the AUSF  1122  and the UE  1101 , receipt of an intermediumte key that was established as a result of the UE  1101  authentication process. Where USIM based authentication is used, the AMF  1121  may retrieve the security material from the AUSF  1122 . AMF  1121  may also include a Security Context Management (SCM) function, which receives a key from the SEA that it uses to derive access-network specific keys. Furthermore, AMF  1121  may be a termination point of RAN CP interface (N2 reference point), a termination point of NAS (N1) signalling, and perform NAS ciphering and integrity protection. 
     AMF  1121  may also support NAS signalling with a UE  1101  over an N3 interworking-function (IWF) interface. The N3IWF may be used to provide access to untrusted entities. N33IWF may be a termination point for the N2 and N3 interfaces for control plane and user plane, respectively, and as such, may handle N2 signalling from SMF and AMF for PDU sessions and QoS, encapsulate/de-encapsulate packets for IPSec and N3 tunnelling, mark N3 user-plane packets in the uplink, and enforce QoS corresponding to N3 packet marking taking into account QoS requirements associated to such marking received over N2. N3IWF may also relay uplink and downlink control-plane NAS (N1) signalling between the UE  1101  and AMF  1121 , and relay uplink and downlink user-plane packets between the UE  1101  and UPF  1102 . The N3IWF also provides mechanisms for IPsec tunnel establishment with the UE  1101 . 
     The SMF  1124  may be responsible for session management (e.g., session establishment, modify and release, including tunnel maintain between UPF and AN node); UE IP address allocation &amp; management (including optional Authorization); Selection and control of UP function; Configures traffic steering at UPF to route traffic to proper destination; termination of interfaces towards Policy control functions; control part of policy enforcement and QoS; lawful intercept (for SM events and interface to LI System); termination of SM parts of NAS messages; downlink Data Notification; initiator of AN specific SM information, sent via AMF over N2 to AN; determine SSC mode of a session. The SMF  1124  may include the following roaming functionality: handle local enforcement to apply QoS SLAB (VPLMN); charging data collection and charging interface (VPLMN); lawful intercept (in VPLMN for SM events and interface to LI System); support for interaction with external DN for transport of signalling for PDU session authorization/authentication by external DN. 
     The NEF  1123  may provide means for securely exposing the services and capabilities provided by 3GPP network functions for third party, internal exposure/re-exposure, Application Functions (e.g., AF  1128 ), edge computing or fog computing systems, etc. In such embodiments, the NEF  1123  may authenticate, authorize, and/or throttle the AFs. NEF  1123  may also translate information exchanged with the AF  1128  and information exchanged with internal network functions. For example, the NEF  1123  may translate between an AF-Service-Identifier and an internal 5GC information. NEF  1123  may also receive information from other network functions (NFs) based on exposed capabilities of other network functions. This information may be stored at the NEF  1123  as structured data, or at a data storage NF using a standardized interfaces. The stored information can then be re-exposed by the NEF  1123  to other NFs and AFs, and/or used for other purposes such as analytics. 
     The NRF  1125  may support service discovery functions, receive NF Discovery Requests from NF instances, and provide the information of the discovered NF instances to the NF instances. NRF  1125  also maintains information of available NF instances and their supported services. 
     The PCF  1126  may provide policy rules to control plane function(s) to enforce them, and may also support unified policy framework to govern network behaviour. The PCF  1126  may also implement a front end (FE) to access subscription information relevant for policy decisions in a UDR of UDM  1127 . 
     The UDM  1127  may handle subscription-related information to support the network entities&#39; handling of communication sessions, and may store subscription data of UE  1101 . The UDM  1127  may include two parts, an application FE and a User Data Repository (UDR). The UDM may include a UDM FE, which is in charge of processing of credentials, location management, subscription management and so on. Several different front ends may serve the same user in different transactions. The UDM-FE accesses subscription information stored in the UDR and performs authentication credential processing; user identification handling; access authorization; registration/mobility management; and subscription management. The UDR may interact with PCF  1126 . UDM  1127  may also support SMS management, wherein an SMS-FE implements the similar application logic as discussed previously. 
     The AF  1128  may provide application influence on traffic routing, access to the Network Capability Exposure (NCE), and interact with the policy framework for policy control. The NCE may be a mechanism that allows the 5GC and AF  1128  to provide information to each other via NEF  1123 , which may be used for edge computing implementations. In such implementations, the network operator and third party services may be hosted close to the UE  1101  access point of attachment to achieve an efficient service delivery through the reduced end-to-end latency and load on the transport network. For edge computing implementations, the 5GC may select a UPF  1102  close to the UE  1101  and execute traffic steering from the UPF  1102  to DN  1103  via the N6 interface. This may be based on the UE subscription data, UE location, and information provided by the AF  1128 . In this way, the AF  1128  may influence UPF (re)selection and traffic routing. Based on operator deployment, when AF  1128  is considered to be a trusted entity, the network operator may permit AF  1128  to interact directly with relevant NFs. 
     As discussed previously, the CN  1120  may include an SMSF, which may be responsible for SMS subscription checking and verification, and relaying SM messages to/from the UE  1101  to/from other entities, such as an SMS-GMSC/IWMSC/SMS-router. The SMS may also interact with AMF  1121  and UDM  1127  for notification procedure that the UE  1101  is available for SMS transfer (e.g., set a UE not reachable flag, and notifying UDM  1127  when UE  1101  is available for SMS). 
     The system  1100  may include the following service-based interfaces: Namf: Service-based interface exhibited by AMF; Nsmf: Service-based interface exhibited by SMF; Nnef: Service-based interface exhibited by NEF; Npcf: Service-based interface exhibited by PCF; Nudm: Service-based interface exhibited by UDM; Naf: Service-based interface exhibited by AF; Nnrf: Service-based interface exhibited by NRF; and Nausf: Service-based interface exhibited by AUSF. 
     The system  1100  may include the following reference points: N1: Reference point between the UE and the AMF; N2: Reference point between the (R)AN and the AMF; N3: Reference point between the (R)AN and the UPF; N4: Reference point between the SMF and the UPF; and N6: Reference point between the UPF and a Data Network. There may be many more reference points and/or service-based interfaces between the NF services in the NFs, however, these interfaces and reference points have been omitted for clarity. For example, an N5 reference point may be between the PCF and the AF; an N7 reference point may be between the PCF and the SMF; an N11 reference point between the AMF and SMF; etc. In some embodiments, the CN  1120  may include an Nx interface, which is an inter-CN interface between the MME (e.g., MME  1021 ) and the AMF  1121  in order to enable interworking between CN  1120  and CN  1020 . 
     Although not shown by  FIG. 11 , system  1100  may include multiple RAN nodes  1111  wherein an Xn interface is defined between two or more RAN nodes  1111  (e.g., gNBs and the like) that connecting to 5GC  1120 , between a RAN node  1111  (e.g., gNB) connecting to 5GC  1120  and an eNB (e.g., a RAN node  1011  of  FIG. 10 ), and/or between two eNBs connecting to 5GC  1120 . 
     In some implementations, the Xn interface may include an Xn user plane (Xn-U) interface and an Xn control plane (Xn-C) interface. The Xn-U may provide non-guaranteed delivery of user plane PDUs and support/provide data forwarding and flow control functionality. The Xn-C may provide management and error handling functionality, functionality to manage the Xn-C interface; mobility support for UE  1101  in a connected mode (e.g., CM-CONNECTED) including functionality to manage the UE mobility for connected mode between one or more RAN nodes  1111 . The mobility support may include context transfer from an old (source) serving RAN node  1111  to new (target) serving RAN node  1111 ; and control of user plane tunnels between old (source) serving RAN node  1111  to new (target) serving RAN node  1111 . 
     A protocol stack of the Xn-U may include a transport network layer built on Internet Protocol (IP) transport layer, and a GTP-U layer on top of a UDP and/or IP layer(s) to carry user plane PDUs. The Xn-C protocol stack may include an application layer signaling protocol (referred to as Xn Application Protocol (Xn-AP)) and a transport network layer that is built on an SCTP layer. The SCTP layer may be on top of an IP layer. The SCTP layer provides the guaranteed delivery of application layer messages. In the transport IP layer point-to-point transmission is used to deliver the signaling PDUs. In other implementations, the Xn-U protocol stack and/or the Xn-C protocol stack may be same or similar to the user plane and/or control plane protocol stack(s) shown and described herein. 
       FIG. 12  illustrates exemplary components of a device  1200  in accordance with some embodiments. In some embodiments, the device  1200  may include application circuitry  1202 , baseband circuitry  1204 , Radio Frequency (RF) circuitry  1206 , front-end module (FEM) circuitry  1208 , one or more antennas  1210 , and power management circuitry (PMC)  1212  coupled together at least as shown. The components of the illustrated device  1200  may be included in a UE or a RAN node. In some embodiments, the device  1200  may include less elements (e.g., a RAN node may not utilize application circuitry  1202 , and instead include a processor/controller to process IP data received from an EPC). In some embodiments, the device  1200  may include additional elements such as, for example, memory/storage, display, camera, sensor, or input/output (I/O) interface. In other embodiments, the components described below may be included in more than one device (e.g., said circuitries may be separately included in more than one device for Cloud-RAN (C-RAN) implementations). 
     The application circuitry  1202  may include one or more application processors. For example, the application circuitry  1202  may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with or may include memory/storage and may be configured to execute instructions stored in the memory/storage to enable various applications or operating systems to run on the device  1200 . In some embodiments, processors of application circuitry  1202  may process IP data packets received from an EPC. 
     The baseband circuitry  1204  may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry  1204  may include one or more baseband processors or control logic to process baseband signals received from a receive signal path of the RF circuitry  1206  and to generate baseband signals for a transmit signal path of the RF circuitry  1206 . Baseband processing circuitry  1204  may interface with the application circuitry  1202  for generation and processing of the baseband signals and for controlling operations of the RF circuitry  1206 . For example, in some embodiments, the baseband circuitry  1204  may include a third generation (3G) baseband processor  1204 A, a fourth generation (4G) baseband processor  1204 B, a fifth generation (5G) baseband processor  1204 C, or other baseband processor(s)  1204 D for other existing generations, generations in development or to be developed in the future (e.g., second generation (2G), sixth generation (6G), etc.). The baseband circuitry  1204  (e.g., one or more of baseband processors  1204 A-D) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry  1206 . In other embodiments, some or all of the functionality of baseband processors  1204 A-D may be included in modules stored in the memory  1204 G and executed via a Central Processing Unit (CPU)  1204 E. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments, modulation/demodulation circuitry of the baseband circuitry  1204  may include Fast-Fourier Transform (FFT), precoding, or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry  1204  may include convolution, tail-biting convolution, turbo, Viterbi, or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments. 
     In some embodiments, the baseband circuitry  1204  may include one or more audio Digital Signal Processor(S) (DSP)  1204 F. The audio DSP(s)  1204 F may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry  1204  and the application circuitry  1202  may be implemented together such as, for example, on a system on a chip (SOC). 
     In some embodiments, the baseband circuitry  1204  may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry  1204  may support communication with an Evolved Universal Terrestrial Radio Access Network (EUTRAN) or other Wireless Metropolitan Area Networks (WMAN), a Wireless Local Area Network (WLAN), a Wireless Personal Area Network (WPAN). Embodiments in which the baseband circuitry  1204  is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry. 
     RF circuitry  1206  may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry  1206  may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry  1206  may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry  1208  and provide baseband signals to the baseband circuitry  1204 . RF circuitry  1206  may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry  1204  and provide RF output signals to the FEM circuitry  1208  for transmission. 
     In some embodiments, the receive signal path of the RF circuitry  1206  may include mixer circuitry  1206   a , amplifier circuitry  1206   b  and filter circuitry  1206   c . In some embodiments, the transmit signal path of the RF circuitry  1206  may include filter circuitry  1206   c  and mixer circuitry  1206   a . RF circuitry  1206  may also include synthesizer circuitry  1206   d  for synthesizing a frequency for use by the mixer circuitry  1206   a  of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry  1206   a  of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry  1208  based on the synthesized frequency provided by synthesizer circuitry  1206   d . The amplifier circuitry  1206   b  may be configured to amplify the down-converted signals and the filter circuitry  1206   c  may be a Low-Pass Filter (LPF) or Band-Pass Filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to the baseband circuitry  1204  for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry  1206   a  of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect. 
     In some embodiments, the mixer circuitry  1206   a  of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry  1206   d  to generate RF output signals for the FEM circuitry  1208 . The baseband signals may be provided by the baseband circuitry  1204  and may be filtered by filter circuitry  1206   c.    
     In some embodiments, the mixer circuitry  1206   a  of the receive signal path and the mixer circuitry  1206   a  of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and upconversion, respectively. In some embodiments, the mixer circuitry  1206   a  of the receive signal path and the mixer circuitry  1206   a  of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry  1206   a  of the receive signal path and the mixer circuitry  1206   a  may be arranged for direct downconversion and direct upconversion, respectively. In some embodiments, the mixer circuitry  1206   a  of the receive signal path and the mixer circuitry  1206   a  of the transmit signal path may be configured for super-heterodyne operation. 
     In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry  1206  may include Analog-To-Digital Converter (ADC) and Digital-To-Analog Converter (DAC) circuitry and the baseband circuitry  1204  may include a digital baseband interface to communicate with the RF circuitry  1206 . 
     In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, although the scope of the embodiments is not limited in this respect. 
     In some embodiments, the synthesizer circuitry  1206   d  may be a fractional-N synthesizer or a fractional N/N+1 synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry  1206   d  may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider. 
     The synthesizer circuitry  1206   d  may be configured to synthesize an output frequency for use by the mixer circuitry  1206   a  of the RF circuitry  1206  based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry  1206   d  may be a fractional N/N+1 synthesizer. 
     In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either the baseband circuitry  1204  or the applications processor  1202  depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by the applications processor  1202 . 
     Synthesizer circuitry  1206   d  of the RF circuitry  1206  may include a divider, a Delay-Locked Loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a Dual Modulus Divider (DMD) and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by either N or N+1 (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle. 
     In some embodiments, synthesizer circuitry  1206   d  may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLO). In some embodiments, the RF circuitry  1206  may include an IQ/polar converter. 
     FEM circuitry  1208  may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas  1210 , amplify the received signals and provide the amplified versions of the received signals to the RF circuitry  1206  for further processing. FEM circuitry  1208  may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry  1206  for transmission by one or more of the one or more antennas  1210 . In various embodiments, the amplification through the transmit or receive signal paths may be done solely in the RF circuitry  1206 , solely in the FEM  1208 , or in both the RF circuitry  1206  and the FEM  1208 . 
     In some embodiments, the FEM circuitry  1208  may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include an LNA to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry  1206 ). The transmit signal path of the FEM circuitry  1208  may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry  1206 ), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas  1210 ). 
     In some embodiments, the PMC  1212  may manage power provided to the baseband circuitry  1204 . In particular, the PMC  1212  may control power-source selection, voltage scaling, battery charging, or DC-to-DC conversion. The PMC  1212  may often be included when the device  1200  is capable of being powered by a battery, for example, when the device is included in a UE. The PMC  1212  may increase the power conversion efficiency while providing desirable implementation size and heat dissipation characteristics. 
     While  FIG. 12  shows the PMC  1212  coupled only with the baseband circuitry  1204 . However, in other embodiments, the PMC  1212  may be additionally or alternatively coupled with, and perform similar power management operations for, other components such as, but not limited to, application circuitry  1202 , RF circuitry  1206 , or FEM  1208 . 
     In some embodiments, the PMC  1212  may control, or otherwise be part of, various power saving mechanisms of the device  1200 . For example, if the device  1200  is in an RRC Connected state, where it is still connected to the RAN node as it expects to receive traffic shortly, then it may enter a state known as Discontinuous Reception Mode (DRX) after a period of inactivity. During this state, the device  1200  may power down for brief intervals of time and thus save power. 
     If there is no data traffic activity for an extended period of time, then the device  1200  may transition off to an RRC Idle state, where it disconnects from the network and does not perform operations such as channel quality feedback, handover, etc. The device  1200  goes into a very low power state and it performs paging where again it periodically wakes up to listen to the network and then powers down again. The device  1200  may not receive data in this state, in order to receive data, it transitions back to RRC Connected state. 
     An additional power saving mode may allow a device to be unavailable to the network for periods longer than a paging interval (ranging from seconds to a few hours). During this time, the device is totally unreachable to the network and may power down completely. Any data sent during this time incurs a large delay and it is assumed the delay is acceptable. 
     Processors of the application circuitry  1202  and processors of the baseband circuitry  1204  may be used to execute elements of one or more instances of a protocol stack. For example, processors of the baseband circuitry  1204 , alone or in combination, may be used execute Layer 3, Layer 2, or Layer 1 functionality, while processors of the application circuitry  1204  may utilize data (e.g., packet data) received from these layers and further execute Layer 4 functionality (e.g., Transmission Communication Protocol (TCP) and User Datagram Protocol (UDP) layers). As referred to herein, Layer 3 may comprise a Radio Resource Control (RRC) layer, described in further detail below. As referred to herein, Layer 2 may comprise a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, and a Packet Data Convergence Protocol (PDCP) layer, described in further detail below. As referred to herein, Layer 1 may comprise a physical (PHY) layer of a UE/RAN node, described in further detail below. 
       FIG. 13  illustrates exemplary interfaces of baseband circuitry in accordance with some embodiments. As discussed above, the baseband circuitry  1204  of  FIG. 12  may comprise processors  1204 A- 1204 E and a memory  1204 G utilized by said processors. Each of the processors  1204 A- 1204 E may include a memory interface,  1304 A- 1304 E, respectively, to send/receive data to/from the memory  1204 G. 
     The baseband circuitry  1204  may further include one or more interfaces to communicatively couple to other circuitries/devices, such as a memory interface  1312  (e.g., an interface to send/receive data to/from memory external to the baseband circuitry  1204 ), an application circuitry interface  1314  (e.g., an interface to send/receive data to/from the application circuitry  1202  of  FIG. 12 ), an RF circuitry interface  1316  (e.g., an interface to send/receive data to/from RF circuitry  1206  of  FIG. 12 ), a wireless hardware connectivity interface  1318  (e.g., an interface to send/receive data to/from Near Field Communication (NFC) components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components), and a power management interface  1320  (e.g., an interface to send/receive power or control signals to/from the PMC  1212 . 
       FIG. 14  is an illustration of a control plane protocol stack in accordance with some embodiments. In this embodiment, a control plane  1400  is shown as a communications protocol stack between the UE  1001  (or alternatively, the UE  1002 ), the RAN node  1011  (or alternatively, the RAN node  1012 ), and the MME  1021 . 
     The PHY layer  1401  may transmit or receive information used by the MAC layer  1402  over one or more air interfaces. The PHY layer  1401  may further perform link adaptation or Adaptive Modulation and Coding (AMC), power control, cell search (e.g., for initial synchronization and handover purposes), and other measurements used by higher layers, such as the RRC layer  1405 . The PHY layer  1401  may still further perform error detection on the transport channels, Forward Error Correction (FEC) coding/decoding of the transport channels, modulation/demodulation of physical channels, interleaving, rate matching, mapping onto physical channels, and Multiple Input Multiple Output (MIMO) antenna processing. 
     The MAC layer  1402  may perform mapping between logical channels and transport channels, multiplexing of MAC Service Data Units (SDUs) from one or more logical channels onto Transport Blocks (TB) to be delivered to PHY via transport channels, de-multiplexing MAC SDUs to one or more logical channels from Transport Blocks (TB) delivered from the PHY via transport channels, multiplexing MAC SDUs onto TBs, scheduling information reporting, error correction through Hybrid Automatic Repeat Request (HARD), and logical channel prioritization. 
     The RLC layer  1403  may operate in a plurality of modes of operation, including: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). The RLC layer  1403  may execute transfer of upper layer Protocol Data Units (PDUs), error correction through Automatic Repeat Request (ARQ) for AM data transfers, and concatenation, segmentation and reassembly of RLC SDUs for UM and AM data transfers. The RLC layer  1403  may also execute re-segmentation of RLC data PDUs for AM data transfers, reorder RLC data PDUs for UM and AM data transfers, detect duplicate data for UM and AM data transfers, discard RLC SDUs for UM and AM data transfers, detect protocol errors for AM data transfers, and perform RLC re-establishment. 
     The PDCP layer  1404  may execute header compression and decompression of IP data, maintain PDCP Sequence Numbers (SNs), perform in-sequence delivery of upper layer PDUs at re-establishment of lower layers, eliminate duplicates of lower layer SDUs at re-establishment of lower layers for radio bearers mapped on RLC AM, cipher and decipher control plane data, perform integrity protection and integrity verification of control plane data, control timer-based discard of data, and perform security operations (e.g., ciphering, deciphering, integrity protection, integrity verification, etc.). 
     The main services and functions of the RRC layer  1405  may include broadcast of system information (e.g., included in Master Information Blocks (MIBs) or System Information Blocks (SIBs) related to the Non-Access Stratum (NAS)), broadcast of system information related to the Access Stratum (AS), paging, establishment, maintenance and release of an RRC connection between the UE and E-UTRAN (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), establishment, configuration, maintenance and release of point to point Radio Bearers, security functions including key management, inter Radio Access Technology (RAT) mobility, and measurement configuration for UE measurement reporting. Said MIBs and SIBs may comprise one or more information elements (IEs), which may each comprise individual data fields or data structures. 
     The UE  1001  and the RAN node  1011  may utilize a Uu interface (e.g., an LTE-Uu interface) to exchange control plane data via a protocol stack comprising the PHY layer  1401 , the MAC layer  1402 , the RLC layer  1403 , the PDCP layer  1404 , and the RRC layer  1405 . 
     The Non-Access Stratum (NAS) protocols  1406  form the highest stratum of the control plane between the UE  1001  and the MME  1021 . The NAS protocols  1406  support the mobility of the UE  1001  and the session management procedures to establish and maintain IP connectivity between the UE  1001  and the P-GW  1023 . 
     The S1 Application Protocol (S1-AP) layer  1415  may support the functions of the S1 interface and comprise Elementary Procedures (EPs). An EP is a unit of interaction between the RAN node  1011  and the CN  1020 . The S1-AP layer services may comprise two groups: UE-associated services and non UE-associated services. These services perform functions including, but not limited to: E-UTRAN Radio Access Bearer (E-RAB) management, UE capability indication, mobility, NAS signaling transport, RAN Information Management (RIM), and configuration transfer. 
     The Stream Control Transmission Protocol (SCTP) layer (alternatively referred to as the SCTP/IP layer)  1414  may ensure reliable delivery of signaling messages between the RAN node  1011  and the MME  1021  based, in part, on the IP protocol, supported by the IP layer  1413 . The L2 layer  1412  and the L1 layer  1411  may refer to communication links (e.g., wired or wireless) used by the RAN node and the MME to exchange information. 
     The RAN node  1011  and the MME  1021  may utilize an S1-MME interface to exchange control plane data via a protocol stack comprising the L1 layer  1411 , the L2 layer  1412 , the IP layer  1413 , the SCTP layer  1414 , and the S1-AP layer  1415 . 
       FIG. 15  is an illustration of a user plane protocol stack in accordance with some embodiments. In this embodiment, a user plane  1500  is shown as a communications protocol stack between the UE  1001  (or alternatively, the UE  1002 ), the RAN node  1011  (or alternatively, the RAN node  1012 ), the S-GW  1022 , and the P-GW  1023 . The user plane  1500  may utilize at least some of the same protocol layers as the control plane  1400 . For example, the UE  1001  and the RAN node  1011  may utilize a Uu interface (e.g., an LTE-Uu interface) to exchange user plane data via a protocol stack comprising the PHY layer  1401 , the MAC layer  1402 , the RLC layer  1403 , the PDCP layer  1404 . 
     The General Packet Radio Service (GPRS) Tunneling Protocol for the user plane (GTP-U) layer  1504  may be used for carrying user data within the GPRS core network and between the radio access network and the core network. The user data transported can be packets in any of IPv4, IPv6, or PPP formats, for example. The UDP and IP security (UDP/IP) layer  1503  may provide checksums for data integrity, port numbers for addressing different functions at the source and destination, and encryption and authentication on the selected data flows. The RAN node  1011  and the S-GW  1022  may utilize an S1-U interface to exchange user plane data via a protocol stack comprising the L1 layer  1411 , the L2 layer  1412 , the UDP/IP layer  1503 , and the GTP-U layer  1504 . The S-GW  1022  and the P-GW  1023  may utilize an S5/S8a interface to exchange user plane data via a protocol stack comprising the L1 layer  1411 , the L2 layer  1412 , the UDP/IP layer  1503 , and the GTP-U layer  1504 . As discussed above with respect to  FIG. 14 , NAS protocols support the mobility of the UE  1001  and the session management procedures to establish and maintain IP connectivity between the UE  1001  and the P-GW  1023 . 
       FIG. 16  illustrates components of a core network in accordance with some embodiments. The components of the CN  1020  may be implemented in one physical node or separate physical nodes including components to read and execute instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium). In embodiments, the components of CN  1120  may be implemented in a same or similar manner as discussed herein with regard to the components of CN  1020 . In some embodiments, Network Functions Virtualization (NFV) is utilized to virtualize any or all of the above described network node functions via executable instructions stored in one or more computer readable storage mediums (described in further detail below). A logical instantiation of the CN  1020  may be referred to as a network slice  1601 . A logical instantiation of a portion of the CN  1020  may be referred to as a network sub-slice  1602  (e.g., the network sub-slice  1602  is shown to include the PGW  1023  and the PCRF  1026 ). 
     NFV architectures and infrastructures may be used to virtualize one or more network functions, alternatively performed by proprietary hardware, onto physical resources comprising a combination of industry-standard server hardware, storage hardware, or switches. In other words, NFV systems can be used to execute virtual or reconfigurable implementations of one or more EPC components/functions. 
       FIG. 17  is a block diagram illustrating components, according to some example embodiments, able to read instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and perform any one or more of the methodologies discussed herein. Specifically,  FIG. 17  shows a diagrammatic representation of hardware resources  1700  including one or more processors (or processor cores)  1710 , one or more memory/storage devices  1720 , and one or more communication resources  1730 , each of which may be communicatively coupled via a bus  1740 . For embodiments where node virtualization (e.g., NFV) is utilized, a hypervisor  1702  may be executed to provide an execution environment for one or more network slices/sub-slices to utilize the hardware resources  1700   
     The processors  1710  (e.g., a Central Processing Unit (CPU), a Reduced Instruction Set Computing (RISC) processor, a Complex Instruction Set Computing (CISC) processor, a graphics processing unit (GPU), a Digital Signal Processor (DSP) such as a baseband processor, an Application Specific Integrated Circuit (ASIC), a Radio-Frequency Integrated Circuit (RFIC), another processor, or any suitable combination thereof) may include, for example, a processor  1712  and a processor  1714 . 
     The memory/storage devices  1720  may include main memory, disk storage, or any suitable combination thereof. The memory/storage devices  1720  may include, but are not limited to any type of volatile or non-volatile memory such as Dynamic Random Access Memory (DRAM), Static Random-Access Memory (SRAM), Erasable Programmable Read-Only Memory (EPROM), electrically Erasable Programmable Read-Only Memory (EEPROM), Flash memory, solid-state storage, etc. 
     The communication resources  1730  may include interconnection or network interface components or other suitable devices to communicate with one or more peripheral devices  1704  or one or more databases  1706  via a network  1708 . For example, the communication resources  1730  may include wired communication components (e.g., for coupling via a Universal Serial Bus (USB)), cellular communication components, NFC components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components. 
     Instructions  1750  may comprise software, a program, an application, an applet, an app, or other executable code for causing at least any of the processors  1710  to perform any one or more of the methodologies discussed herein. The instructions  1750  may reside, completely or partially, within at least one of the processors  1710  (e.g., within the processor&#39;s cache memory), the memory/storage devices  1720 , or any suitable combination thereof. Furthermore, any portion of the instructions  1750  may be transferred to the hardware resources  1700  from any combination of the peripheral devices  1704  or the databases  1706 . Accordingly, the memory of processors  1710 , the memory/storage devices  1720 , the peripheral devices  1704 , and the databases  1706  are examples of computer-readable and machine-readable medium. 
     In some embodiments, the electronic device(s), network(s), system(s), chip(s) or component(s), or portions or implementations thereof, of any figure herein may be configured to perform one or more processes, techniques, or methods as described herein, or portions thereof. 
     EXAMPLES 
     Example 1 may include an apparatus configured to be employed in a User Equipment (UE), comprising: a Radio Frequency (RF) circuitry interface; and processing circuitry, configured to: perform Channel-State Information (CSI) measurement for communication in unlicensed spectrum; generate data for feedback according to the CSI measurement; and send the data for feedback to RF circuitry via the RF circuitry interface, wherein a frame structure of a data channel for the communication begins with a downlink (DL) transmission or soon after an initial signal, and wherein the CSI measurement includes to measure Channel Quality Information (CQI) for a sub-band (e.g., one or more sub-bands). 
     Example 2 may include the subject matter of Example 1, wherein the frame structure is a DL-uplink(UL)-DL-UL frame structure. 
     Example 3 may include the subject matter of Example 1 or 2, wherein a total band for the communication is divided into multiple sub-bands, and wherein the processing circuitry is further configured to measure the CQI for each sub-band. 
     Example 4 may include the subject matter of any one of Examples 1 to 3, wherein the processing circuitry is further configured to generate data for a hopping sequence for the communication in a pseudo random manner, and wherein a constraint is added to limit the separation in frequency among two adjacent channels. 
     Example 5 may include the subject matter of Example 2, wherein the DL-UL-DL-UL frame structure includes a frequency tuning period, a Clear Channel Assignment (CCA) and enhanced CCA (eCCA) period, a presence signal period, a DL subframes period, a UL subframes period, a CCA and eCCA period, a DL subframes period and a UL subframes period in sequence. 
     Example 6 may include the subject matter of Example 1, wherein the frame structure is a DL-UL frame structure. 
     Example 7 may include the subject matter of any one of Examples 1, 3 and 6, wherein the processing circuitry is further configured to: perform long term measurement of the CQI on a specific sub-band based on continuous DL transmissions over the specific sub-band, and generate data for periodic feedback as for reporting mode 1-0, where the periodicity is to be configured through Radio Resource Control (RRC) or Downlink Control Information (DCI) signaling. 
     Example 8 may include the subject matter of any one of Examples 1, 3, 6 and 7, wherein the processing circuitry is further configured to generate the CQI for all sub-bands or only the CQI related to a specific sub-band periodically. 
     Example 9 may include the subject matter of Example any one of Examples 1, 3 and 6 to 8, wherein the number of sub-bands is fixed or predefined or is flexibly changed through higher layer signaling. 
     Example 10 may include the subject matter of any one of Examples 1, 3 and 6 to 8, wherein periodic reporting mode 3-0 or 3-1 is to be reused, or periodic mode 2-0 and/or 2-1 is to be used where the M sub-bands are selected based on a whitelist. 
     Example 11 may include the subject matter of Example 1 or 6, wherein the processing circuitry is further configured to compute the CQI based on the measurement of a previous DL transmission occurred over an adjacent channel in a previous hop. 
     Example 12 may include the subject matter of Example 1 or 6, wherein active channels for the communication having high correlation are to be chosen by an eNB. 
     Example 13 may include the subject matter of Example 1, wherein the CQI is reported as wideband CQI. 
     Example 14 may include the subject matter of Example 1, wherein the CQI includes wideband CQI and sub-band CQI, and the sub-band CQI is 2 bit differential field based on the wideband CQI. 
     Example 15 may include the subject matter of Example 1, wherein the processing circuitry is configured to compute the CQI as follows: a total bandwidth constructed by the channels in a whitelist; a total bandwidth of multiple adjacent channels; and a total bandwidth of a specific channel. 
     Example 16 may include the subject matter of Example 1, wherein the processing circuitry is further configured to evaluate the CQI according to a UE preferred channel index or Resource Blocks (RBs). 
     Example 17 may include the subject matter of Example 1 or 16, wherein the processing circuitry is further configured to evaluate sub-band CQI as follows: the CQI based on one specific channel; and the CQI on selected RBs within the one specific channel. 
     Example 18 may include the subject matter of Example 1, wherein the CQI is reported aperiodically. 
     Example 19 may include the subject matter of any one of Examples 1 to 18, wherein the communication is enhanced Machine Type Communication (eMTC). 
     Example 20 may include the subject matter of any one of Examples 1 to 19, wherein the Rank Indicator (RI) is not reported, and the rank is fixed to 1. 
     Example 21 may include the subject matter of any one of Examples 1 to 19, wherein only the CQI is reported in the feedback and mode x-2 and x-3 are not supported. 
     Example 22 may include the subject matter of Example 1 or 19, wherein the feedback contains a wideband CQI and a wideband Precoder Matrix Indicator (PMI). 
     Example 23 may include the subject matter of Example 1 or 19, wherein frequency-selective CQI is supported. 
     Example 24 may include the subject matter of Example 1 or 19, wherein mode 2-1 and/or 3-1 is supported. 
     Example 25 may include the subject matter of any one of Examples 1, 13 and 19, wherein only mode 1-1 is supported, which includes a wideband CQI, and a single PMI on the wideband CQI. 
     Example 26 may include the subject matter of any one of Examples 1, 13 and 19, wherein mode 1-1 is supported with other reporting modalities. 
     Example 27 may include the subject matter of any one of Examples 1, 13 and 19, wherein only mode 2-0 is supported as the legacy eMTC systems or in conjunction with other modalities, e.g., mode 1-0 and/or mode 1-1. 
     Example 28 may include the subject matter of any one of Examples 1, 13 and 19, wherein mode 2-1 is supported. 
     Example 29 may include the subject matter of any one of Examples 1, 13 and 19, wherein an offset may be contained within the DCI that triggers the CQI measurement. 
     Example 30 may include the subject matter of Example 1 or 19, wherein the sub-bands are RRC configured. 
     Example 31 may include the subject matter of Example 1 or 19, wherein the configuration of the sub-bands is encoded within the bitmap which indicates the list of available channels. 
     Example 32 may include a computer-readable medium (e.g., a non-transitory computer-readable medium) comprising instructions that, when executed (e.g., by one or more processors of an electronic device), cause an electronic device to: perform a Channel-State Information (CSI) measurement and feedback procedure for communication in unlicensed spectrum, wherein the CSI measurement and feedback procedure is over a frame structure of a data channel, wherein the frame structure is a DL-UL frame structure including a frequency tuning period, a CCA and eCCA period, a presence signal period, a DL subframes period and a UL subframes period in sequence, wherein a total band for the communication is divided into multiple sub-bands, and wherein the processing circuitry is further configured to measure the CQI for each sub-band. 
     Example 33 may include a computer-readable medium (e.g., a non-transitory computer-readable medium) comprising instructions that, when executed (e.g., by one or more processors of an electronic device), cause an electronic device to: perform the Channel-State Information (CSI) measurement and feedback procedure for communication in unlicensed spectrum described above. 
     Example 34 may include a method comprising the Channel-State Information (CSI) measurement and feedback procedure for communication in unlicensed spectrum described above. 
     Example 35 may include a computer-readable medium (e.g., a non-transitory computer-readable medium) comprising instructions that, when executed (e.g., by one or more processors of an electronic device), cause an electronic device to: generate a Sounding Reference Signal (SRS) for uplink (UL) channel estimation for communication in unlicensed spectrum, wherein the communication is over a frame structure of a data dwell time comprising a downlink (DL) dwell time and a UL dwell time, wherein a DL transmission in the DL dwell time is to trigger transmission of the SRS within an available UL dwell time. 
     Example 36 may include the subject matter of Example 35, wherein Long Term Evolution (LTE) signal generation mechanisms are reused. 
     Example 37 may include the subject matter of Example 35 or 36, wherein the communication for the SRS is to use 6 Resource Blocks (RBs) within a data hop, and the SRS is generated to have a comb-like structure within the 6 RBs. 
     Example 38 may include the subject matter of any one of Examples 35 to 37, wherein the SRS is to occupy all tones across the 6 RBs using different Cyclic Delay Diversity (CDD) or Orthogonal Cover Codes (OCCs). 
     Example 39 may include the subject matter of any one of Examples 35 to 38, wherein the instructions, when executed, cause the electronic device to: generate SRS transmission hopping for the SRS in a carrier-specific manner; generate hopping patterns for the SRS transmission hops based on a data hopping pattern; and determine the data hopping pattern based on a function of a Physical Cell Identity (PCI) and System Frame Number (SFN)+eFrame number. 
     Example 40 may include the subject matter of any one of Examples 35 to 39, wherein the frame structure comprises a DL-UL sequence or DL-UL-DL-UL sequence. 
     Example 41 may include the subject matter of any one of Examples 35 to 39, wherein a total band over which SRS transmissions in the communication are to hop is divided over multiple sub-bands, and wherein the SRS transmissions are for all sub-bands on a periodic basis or are over a specific sub-band configured through higher layer signaling comprising Radio Resource Control (RRC) signaling or Non-Access Stratum (NAS) signaling. 
     Example 42 may include the subject matter of any one of Examples 35 to 39, wherein the instructions, when executed, cause the electronic device to: detect a configuration via higher layer signaling, wherein the higher layer signaling comprises RRC signaling or NAS signaling; determine or identify, based on the configuration, a number of sub-bands and/or a number of times on which SRS transmissions are to be performed over a specific sub-band before the SRS is transmitted on a different band; and determine or identify a bandwidth of the sub-band. 
     Example 43 may include the subject matter of any one of Examples 35 to 39, wherein the instructions, when executed, cause the electronic device to: generate a hopping sequence such that channels have a specific separation in frequency among two adjacent channels and/or the channels are sufficiently correlated, wherein the SRS is to be communicated on a periodic basis or on an aperiodic basis. 
     Example 44 may include the subject matter of any one of Examples 35 to 38, wherein in the communication, the SRS is transmitted in a Physical Resource Block (PRB) fashion that is performed through an entire 6 PRBs through hopping in a frequency domain such that a sequence of SRS transmissions jointly spans a frequency range of interest. 
     Example 45 may include the subject matter of any one of Examples 35 to 44, wherein in the communication, the SRS is transmitted upon activation of the SRS and without regard to a DL Clear Channel Assessment (CCA)/enhanced CCA (eCCA). 
     Example 46 may include the subject matter of any one of Examples 35 to 45, wherein SRS opportunities including the periodic SRS opportunities are associated with a data dwell time, and wherein an SRS opportunity is automatically disabled at an end of an available data dwell time even when a periodic SRS transmission is activated. 
     Example 47 may include the subject matter of any one of Examples 35 to 39, wherein a sub-band configuration for the SRS is a same configuration or a different configuration as a sub-band configuration for Channel State Information (CSI)-Reference Signal (RS) for DL channel measurement. 
     Example 48 may include the subject matter of any one of Examples 35 to 39, wherein a number of sub-bands and/or a number of times on which SRS transmissions are to be performed over a specific sub-band before the SRS is transmitted on a different band is predefined, and wherein a bandwidth of the sub-band is predefined. 
     Example 49 may include the subject matter of any one of Examples 35 to 39, wherein the instructions, when executed, cause the electronic device to: detect a configuration via higher layer signaling, wherein the higher layer signaling comprises RRC signaling or NAS signaling; and determine or identify, based on the configuration, a periodicity for transmitting the SRS, and wherein periodic SRS transmission is for a long term channel state estimate on a specific sub-band based on continuous SRS transmissions over the specific sub-band. 
     Example 50 may include the subject matter of any one of Examples 35 to 39, wherein in the communication, the transmission of the SRS for a sub-band is by way of a wideband SRS transmission that allows for sounding of an entire frequency range of interest with the transmission of the SRS. 
     Example 51 may include the subject matter of any one of Examples 35 to 39, wherein in the communication, the transmission of the SRS is over a narrowband transmission that is hopping in a frequency domain such that a sequence of the SRS jointly spans a range of interest in a long run. 
     Example 52 may include the subject matter of any one of Examples 35 to 39, wherein: the signal generation includes generating a Demodulation Reference Signal (DM-RS) to be used to estimate channel information; and in the communication, the DM-RS is transmitted over a Physical Uplink Shared Channel (PUSCH). 
     Example 53 may include the subject matter of any one of Examples 35 to 39, wherein the electronic device is implemented in or by an enhanced Machine Type Communication (eMTC) User Equipment (UE). 
     Example 54 may include a method comprising the SRS transmission and/or channel-state estimation for communication in unlicensed spectrum as described above. 
     The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of embodiments to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments.

Metadata:
Filing Date: 20180917
Publication Date: 20221011
Grant Date: 20221011
Priority Date: 20170915
Inventors: TALARICO, Salvatore
NIU, HUANING
CHANG, Wenting
Assignee: APPLE INC
CPC Classifications: [{"code": "H04L5/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0057", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0632", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0057", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0048", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W4/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B7/0626", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L25/0228", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W74/0808", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L27/0006", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/0006", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W76/27", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L5/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W16/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/713", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W4/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W74/0808", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L5/0012", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/713", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W16/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W24/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L25/0228", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L5/0012", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0051", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0051", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W24/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W24/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0632", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W74/0808", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L5/0051", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0626", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W4/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L25/0228", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W16/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0057", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/713", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W76/27", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L27/0006", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0012", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0048", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 65230018