WO2017074246A1

WO2017074246A1 - Systems and methods of performing data transmission and reception in a communication system

Info

Publication number: WO2017074246A1
Application number: PCT/SE2016/051036
Authority: WO
Inventors: Xingqin LIN; Miguel Lopez; Shashi Kant; Yutao Sui; Asbjörn GRÖVLEN; Niklas Johansson; Yi-Pin Eric Wang; Ansuman ADHIKARY
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2015-10-26
Filing date: 2016-10-26
Publication date: 2017-05-04

Abstract

Systems and methods of performing data transmission and reception in a communication system are presented. In one exemplary embodiment, a method implemented by a wireless device for transmitting a block of user or pilot data in a communication system may include generating (1301) a transmit signal that represents the block of user or pilot data. The transmit signal may include a guard period excluding any of the user or pilot data in the block. Further, the transmit signal may include, after the guard period, a cyclic prefix formed from a tail end portion of the block of user or pilot data. In addition, the transmit signal may include, after the cyclic prefix, multiple contiguous repetitions of the block of user or pilot data. The method may also include transmitting (1303) the generated transmit signal.

Description

SYSTEMS AND METHODS OF PERFORMING DATA TRANSMISSION AND RECEPTION IN

A COMMUNICATION SYSTEM

RELATED APPLICATIONS

This application claims priority to U.S. Provisional patent Application Serial Number 62/246534 filed 26 October 2015, the entire contents of which are incorporated herein by reference.

FIELD OF DISCLOSURE

The present disclosure relates generally to the field of communications, and in particular to performing data transmission and reception in a communication system. BACKGROUND

Machine-type communications (MTC) or machine-to-machine (M2M) communications envisions that everything that benefits being connected will be connected, which is also referred to as the Internet of things (loT). MTC/M2M communications offer a growth opportunity for the 3^rd Generation Partnership Project (3GPP) ecosystem and also a new revenue generation for mobile operators. In order to support loT, the 3GPP community/operators have to address usage scenarios with devices that may be connected in challenging coverage conditions, e.g., indoor and basements. Moreover, MTC devices are expected to be energy efficient (e.g., battery life of ten years), and have low cost such that they may be deployed in massive scale. An enhanced coverage improvement target of fifteen to twenty decibels (15-20 dB) is required to support MTC devices that are deployed in challenging locations, e.g. deep inside buildings, and to compensate for signal-to-noise ratio (SNR) loss due to complexity reduction techniques.

The Networked Society and Internet of Things (loT) is associated with new requirements for cellular networks such as with respect to device cost, battery lifetime and coverage. To reduce device and module cost, a system-on-a-chip (SoC) solution with integrated power amplifier (PA) is desirable. However, the current state-of-the-art of PA technology only allows about twenty to twenty-three decibel-milliwatts (20-23 dBm) transmit power when the PA is integrated in the SoC. This constraint limits uplink coverage from a user terminal to a serving base station. To improve this uplink coverage using a PA integrated in an SoC, it is necessary to avoid PA backoff. PA backoff is needed when the communication signal has a non-unity peak-to-average power ratio (PAPR). The higher the PAPR, the higher the PA backoff. Higher PA backoff also reduces PA efficiency, resulting in increased power consumption by the PA. Thus, for wireless loT technologies, designing an uplink communication signal that has a lower PAPR is important for achieving the performance objectives concerning device cost, battery lifetime and coverage. Currently, 3^rd Generational Partnership Project (3GPP) is working on extending the Long Term Evolution (LTE) standard to better support loT applications. 3GPP is standardizing Narrow-band loT (NB loT) technologies that may be deployed using one hundred and eighty kilohertz (180 kHz) system bandwidth, such as described by 3GPP RP-151621 , New Work Item: Narrowband IOT (NB-IOT), Qualcomm, Sept. 2015, Phoenix, AZ. NB loT is required to support three different modes of operation: stand-alone operation, guard-band operation and in-band operation. The stand-alone operation utilized, for example, the spectrum currently being used by GSM/EDGE systems as a replacement for one or more GSM carriers. The guard-band operation utilizes the unused resource blocks within a guard band of an LTE carrier. The in- band operation utilizes resource blocks within a normal LTE carrier. A leading candidate solution for NB loT is an LTE-based NB-LTE solution. For this solution, the LTE uplink is based on single-carrier frequency-division multiple-access (SC-FDMA) modulation for uplink data and control channels. SC-FDMA requires certain accuracy of timing advancement to preserve orthogonality between UEs.

In LTE, an uplink random access procedure is used by user equipment (UE) to access an LTE network. The random access signal also allows the base station to estimate the timing advance needed so that the subsequent signals transmitted by a UE, e.g. Physical Uplink Shared Channel (PUSCH) signals, may arrive at the base station within the cyclic prefix interval (CP). By doing so, orthogonality among uplink modulation signals is maintained, thanks to the Single-Carrier Frequency-Division Multiple-Access (SC-FDMA) scheme employed in LTE.

However, a poor timing advance estimate may result in the loss of orthogonality among the uplink modulation signals and degraded PUSCH performance.

The performance objectives of NB loT include ultra-low module cost, twenty decibels (20 dB) coverage extension, and ten-year battery lifetime. To achieve these objectives, it is desirable to make the PAPR as close to zero decibels (0 dB) as possible, especially for UEs that are in poor coverage areas. One solution to achieve close to zero decibels (0 dB) PAPR for the random access signal is to use a frequency-hopping, phase-continuous single subcarrier signal. However, such a random access signal may result in a poor timing advance estimate at the base station due to its narrow signal bandwidth characteristics. For example, the error in a timing advance estimate may be as large as thirty microseconds (30 μεβα), which exceeds the LTE normal CP of 4.7 με. The sub-carrier spacing of NB-LTE may be scaled down from a fifteen kilohertz (15 kHz) subcarrier spacing for an uplink shared channel in LTE to 2.5 kHz subcarrier spacing, such as described by 3GPP R1-156010, NB-LTE - General L1 concept description, Ericsson. In this example, scaling down the subcarrier spacing by a factor of six compared to LTE provides a six times increase in CP, which helps cope with poor timing accuracy. However, using 2.5 kHz subcarrier spacing for NB loT may introduce a coexistence problem with LTE for the aforementioned in-band and guard-band operations. Although, using 2.5 kHz subcarrier spacing with a longer CP helps preserve orthogonality between NB loT UEs when the timing advance accuracy is poor, it does not preserve orthogonality with UEs using neighboring LTE physical resource blocks (PRBs). Accordingly, there is a need for improved techniques for performing data transmission and reception in a communication system such as an NB-loT system. In addition, other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description and embodiments, taken in conjunction with the accompanying figures and the foregoing technical field and background.

The Background section of this document is provided to place embodiments of the present disclosure in technological and operational context, to assist those of skill in the art in understanding their scope and utility. Unless explicitly identified as such, no statement herein is admitted to be prior art merely by its inclusion in the Background section.

SUMMARY

The following presents a simplified summary of the disclosure in order to provide a basic understanding to those of skill in the art. This summary is not an extensive overview of the disclosure and is not intended to identify key/critical elements of embodiments of the disclosure or to delineate the scope of the disclosure. The sole purpose of this summary is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.

Briefly described, embodiment of the present disclosure relate to performing data transmission and reception in a communication system. According to one aspect, a method implemented by a wireless device for transmitting a block of user or pilot data in a

communication system may include generating a transmit signal that represents the block of user or pilot data. The transmit signal may include a guard period excluding any of the user or pilot data in the block. Further, the transmit signal may include, after the guard period, a cyclic prefix formed from a tail end portion of the block of user or pilot data. In addition, the transmit signal may include, after the cyclic prefix, multiple contiguous repetitions of the block of user or pilot data. The method may also include transmitting the generated transmit signal.

According to another aspect, the method may include obtaining the tail end portion of the block of user or pilot data as comprising a sub-block that has a defined length and that is positioned at a tail end of the block of user or pilot data. Further, the defined length may be an integer multiple of a number of the contiguous repetitions of the block of user or pilot data in the transmit signal. The method may also include forming the cyclic prefix from the tail end portion of the block of user or pilot data.

According to another aspect, the step of transmitting may include transmitting the transmit signal at a time such that the transmit signal arrives at a receiver as comprising multiple cyclically-shifted versions of the block of user or pilot data, with each version prefixed by a tail end portion of that version.

According to another aspect, the cyclically-shifted versions may cyclically shift the block of user or pilot data to a different extent across the transmit signal.

According to another aspect, the cyclically-shifted versions may cyclically shift the block of user or pilot data to a progressively lesser extent across the transmit signal towards an end of the transmit signal.

According to another aspect, the steps of generating and transmitting may be performed when a timing advance error associated with a previously generated and transmitted transmit signal exceeds a defined threshold.

According to another aspect, the timing advance error may be estimated based on a signal strength of a signal received by the wireless device from a serving base station.

According to another aspect, the method may include, when the timing advance error is less than the defined threshold, transmitting the block of user or pilot data with a shorter cyclic prefix than when the timing advance exceeds the defined threshold. Further, the block of user or pilot data may be transmitted without the guard period or without the multiple repetitions.

According to another aspect, the method may include receiving, from a serving base station, an indication to perform said generating and transmitting. Further, the steps of generating and transmitting may be responsive to this indication.

According to another aspect, the method may include dynamically selecting between generating the transmit signal to comprise the guard period, cyclic prefix, and multiple contiguous repetitions and generating the transmit signal to comprise a shorter cyclic prefix intervening between each block of user or pilot data within the transmit signal. Further, this shorter cyclic prefix may be shorter than the cyclic prefix.

According to another aspect, the method may include selecting a length of the cyclic prefix according to a scheduling grant received from a serving base station.

According to another aspect, the transmit signal may have a subcarrier spacing of 3.75 kHz.

According to another aspect, the transmit signal may be an uplink OFDM signal.

According to another aspect, the method may include multiplexing the user data and the pilot data to obtain the block of user or pilot data.

According to another aspect, the transmit signal may be a narrowband Internet of Things (NB-loT) signal. According to another aspect, the method may include encoding information to obtain the block of user or pilot data.

According to another aspect, the step of transmitting may be on a physical data channel.

According to another aspect, a timing advance error that corresponds to the transmitted signal may be no more than the guard period.

According to another aspect, a timing advance error that corresponds to the transmitted signal may be at least the guard period.

According to another aspect, the transmitted signal may be associated with a contention- based, random access procedure.

According to another aspect, the transmitted signal may exclude a preamble.

According to another aspect, the wireless device may be a user equipment.

According to another aspect, the user data may include acknowledgment (ACK) or not acknowledged (NAK) information.

According to another aspect, the user data may include control information.

According to one aspect, a wireless device for transmitting a block of user or pilot data in a communication system may include a processing circuit. Further, the processing circuit may be configured to generate a transmit signal that represents the block of user or pilot data. The transmit signal may include a guard period excluding any of the user or pilot data in the block. Further, the transmit signal may include, after the guard period, a cyclic prefix formed from a tail end portion of the block of user or pilot data. In addition, the transmit signal may include, after the cyclic prefix, multiple contiguous repetitions of the block of pilot or user data. The

processing circuit may also be configured to transmit the generated transmit signal.

According to one aspect, a method implemented by a radio network node for receiving a block of user or pilot data in a communication system may include receiving, by the radio network node, a receive signal that represents the block of user or pilot data. The receive signal may include a cyclic prefix formed from a tail end portion of the block of user or pilot data.

Further, the receive signal may include, after the cyclic prefix, multiple contiguous repetitions of the block of user or pilot data. The method may also include removing any portion of the receive signal that was received prior to the cyclic prefix. Further, the method may include extracting the block of user or pilot data from the receive signal.

According to one aspect, a method implemented by a radio network node may include receiving, by the radio network node, a receive signal that comprises a sequence of OFDM symbols representing a block of user or pilot data. Further, the method may include removing a head-end portion of each OFDM symbol in the sequence to obtain a sequence of OFDM symbol data portions. Also, the method may include extracting the block of user or pilot data from the OFDM symbol data portions. The step of extracting may include phase rotating at least one OFDM symbol data portion based on a cyclic shift of that data portion relative to another OFDM symbol data portion. The step of extracting may also include combining those OFDM symbol data portions as phase rotated.

According to another aspect, the method may include determining a timing advance with which the receive signal is to be transmitted. Further, the steps of receiving, removing, and extracting may be performed responsive to determining that the timing advance exceeds a defined threshold. In addition, the method may include signaling that the receive signal is to be transmitted with this timing advance.

According to another aspect, the step of phase rotating may include phase rotating by a predefined length of the head-end portion of each OFDM symbol in the sequence.

According to another aspect, the method may include selecting a length of a cyclic prefix that is to be used to form the receive signal for transmission by prefixing that cyclic prefix to multiple contiguous repetitions of the block of user or pilot data. Further, the method may include signaling the selected length within a scheduling grant.

According to one aspect, a radio network node may include a rpocessing circuit. The processing circuit may be configured to receive a receive signal that comprises a sequence of OFDM symbols representing a block of user or pilot data. Further, the processing circuit may be configured to remove a head-end portion of each OFDM symbol in the sequence to obtain a sequence of OFDM symbol data portions. Also, the processing circuit may be configured to extract the block of user or pilot data from the OFDM symbol data portions by phase rotating at least one OFDM symbol data portion based on a cyclic shift of that data portion relative to another OFDM symbol data portion and by combining those OFDM symbol data portions as phase rotated.

According to another aspect, the radio network node may be a base station.

According to one aspect, a method by a base station for performing data reception in a communication system may include receiving, by the base station, from a first wireless device, a first uplink modulation signal having a plurality of contiguous modulation symbols, wherein an initial modulation symbol of the plurality of contiguous modulation symbols includes at least a portion of a guard period, each of a remaining contiguous modulation symbols includes at least a portion of a phase-rotated repeated user or pilot data of a modulation symbol, each of the remaining contiguous modulation symbols includes a progressively different phase rotation of the repeated user or pilot data of the modulation symbol, and at least one of the initial modulation symbol and an adjacent modulation symbol of the plurality of contiguous modulation symbols includes at least a portion of a first cyclic prefix. According to another aspect, the step of receiving may include receiving a combined signal that includes the first uplink modulation signal and a second uplink modulation signal transmitted by a second wireless device. Further, the second uplink modulation signal may include a plurality of modulation symbols with each modulation symbol having a second cyclic prefix and user or pilot data.

According to another aspect, a length of the first cyclic prefix may be longer than a length of the second cyclic prefix.

According to another aspect, the first uplink modulation signal may be substantially orthogonal to the second uplink modulation signal.

According to another aspect, the first uplink modulation signal may be capable of a timing advance that is greater than a timing advance of the second uplink modulation signal.

According to another aspect, a subcarrier spacing of the first uplink modulation signal may be equivalent to a subcarrier spacing of the second uplink modulation signal.

According to another aspect, a subcarrier spacing of the first uplink modulation signal is less than a subcarrier spacing of the second uplink modulation signal.

According to another aspect, a subcarrier spacing of the first uplink modulation signal may be an integer multiple of a subcarrier spacing of the second uplink modulation signal.

According to another aspect, a subcarrier spacing of the first uplink modulation signal may be 3.75 kHz and a subcarrier spacing of the second uplink modulation signal may be 15 kHz.

According to another aspect, the method may include demodulating the remaining contiguous portion of the plurality of contiguous modulation symbols of the first uplink modulation signal to obtain the plurality of phase-rotated repeated user or pilot data. Further, the method may include phase rotating each of the plurality of phase-rotated repeated user or pilot data to obtain a plurality of phase-aligned repeated user or pilot data. Also, the method may include determining a channel estimate using the plurality of phase-aligned repeated user or pilot data responsive to determining that the plurality of phase-aligned repeated user or pilot data is associated with a pilot symbol. In addition, the method may include channel compensating the plurality of phase-aligned repeated user or pilot data using the channel estimate to obtain a plurality of channel-compensated repeated user or pilot data. The method may also include combining the plurality of channel-compensated repeated user or pilot data to obtain a data symbol.

According to another aspect, the step of combining may include coherent combining of the plurality of channel-compensated repeated data. According to another aspect, the step of combining may include using log-likelihood ratios.

According to one aspect, a base station for performing data reception in a

communication system may include a processing circuit. Further, the processing circuit may be configured to receive, from a first wireless device, a first uplink modulation signal having a plurality of contiguous modulation symbols. An initial modulation symbol of the plurality of contiguous modulation symbols may include at least a portion of a guard period. Each of a remaining contiguous modulation symbols may include at least a portion of a phase-rotated repeated user or pilot data of a modulation symbol. Also, each of the remaining contiguous modulation symbols may include a progressively different cyclic shift of the repeated user or pilot data of the modulation symbol. In addition, at least one of the initial modulation symbol and an adjacent modulation symbol of the plurality of contiguous modulation symbols may include at least a portion of a first cyclic prefix.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the disclosure are shown. However, this disclosure should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like numbers refer to like elements throughout.

FIG. 1 illustrates one embodiment of a system for performing data transmission and reception in a communication system in accordance with various aspects as described herein.

FIG. 2 shows an example of uplink modulation signals transmitted by UEs and received at a base station in a communication system that does not use timing advance.

FIG. 3 shows an example of uplink modulation signals transmitted by UEs and received at a base station in a communication system that uses timing advance.

FIG. 4 illustrates one embodiment of a system for performing data transmission and reception in a communication system in accordance with various aspects as described herein.

FIG. 5 illustrates another embodiment of a system for performing data transmission and reception in a communication system in accordance with various aspects as described herein.

FIG. 6 illustrates another embodiment of a system for performing data transmission and reception in a communication system in accordance with various aspects as described herein.

FIG. 7 illustrates one embodiment of a repetition pattern of data symbols and pilot symbols in a communication system in accordance with various aspects as described herein. FIG. 8 shows another embodiment of a system for performing data reception in a communication system in accordance with various aspects as described herein.

FIG. 9 shows another embodiment of a system for performing data reception in a communication system in accordance with various aspects as described herein.

FIG. 10 shows another embodiment of a system for performing data reception in a communication system in accordance with various aspects as described herein.

FIG. 11 shows another embodiment of a system for performing data reception in accordance with various aspects as described herein.

FIG. 12 shows another embodiment of a system for performing data transmission and reception in a communication system in accordance with various aspects as described herein.

FIG. 13 shows one embodiment of a method of performing data transmission in a communication system in accordance with various aspects as described herein.

FIG. 14 shows another embodiment of a method of performing data reception in a communication system in accordance with various aspects as described herein.

FIG. 15 shows another embodiment of a method of performing data reception in a communication system in accordance with various aspects as described herein.

FIG. 16 shows one embodiment of a wireless device in accordance with various aspects as described herein.

FIGs. 17A-B show other embodiments of a wireless device in accordance with various aspects as described herein. FIG. 17C illustrates one embodiment of a user equipment (UE) in accordance with various aspects described herein.

FIG. 18A-B show other embodiments of a network node in accordance with various aspects as described herein. FIG. 18C illustrates one embodiment of a base station in accordance with various aspects described herein. DETAILED DESCRIPTION

For simplicity and illustrative purposes, the present disclosure is described by referring mainly to an exemplary embodiment thereof. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be readily apparent to one of ordinary skill in the art that the present disclosure may be practiced without limitation to these specific details. In this description, well known methods and structures have not been described in detail so as not to unnecessarily obscure the present disclosure. This disclosure includes describing systems and methods of performing data transmission in a communication system. For instance, FIG. 1 illustrates one embodiment of a system 100 for performing data transmission and reception in a communication system in accordance with various aspects as described herein. In FIG. 1 , the system 100 includes a base station 101 and UEs 111-115 served by the base station 101 in its coverage area 103. The system 100 in some embodiments supports transmission by a UE of either a first or second uplink modulation signal. The first and second uplink modulation signals support different ranges of timing advances. As designated herein, the first uplink modulation signal supports a larger timing advance than the second uplink modulation signal.

In one or more embodiments, the first uplink modulation signal may include contiguous modulation symbols. Further, an initial modulation symbol of the contiguous modulation symbols may include at least a portion of a guard period. Each of the remaining contiguous modulation symbols may include at least a portion of a phase-rotated repeated data of a certain modulation symbol such as a modulated data symbol or a modulated pilot symbol. Also, each of the remaining contiguous modulation symbols may include a different cyclic shift of the phase-rotated repeated data of the certain modulation symbol. In one example, each of the remaining contiguous modulation symbols may include a progressively lower cyclic shift of the repeated data. In addition, at least one of the initial modulation symbol and an adjacent modulation symbol of the plurality of contiguous modulation symbols may include a first cyclic prefix. The first uplink modulation signal may support a first timing advance up to the guard period plus an interval of the first cyclic shift. The second uplink modulated signal may include one or more modulation symbols with each modulation symbol including a second cyclic shift followed by data. The second cyclic shift may have different intervals for each of the modulation symbols. The second uplink modulation signal may support a second timing advance up to an interval of the second CP of a first modulation symbol.

In FIG. 1 , the first UE 111 may be close enough to the base station 101 so that the first UE 111 may use the second uplink modulation signal with little or no timing advance. The second and third UEs 112-113 may also use the second uplink modulation signal with a timing advance of less than about the interval of the second CP. However, since the fourth UE 114 is on a fringe of the coverage area 103 of the base station 101 , the fourth UE 114 may have a timing advance that is at least the interval of the second CP. If the fourth UE 114 uses the second uplink modulation signal, then the orthogonality between the second uplink modulation signal transmitted by the fourth UE 114 and the other uplink modulation signals transmitted by the first, second and third UEs 111-113 may be lost, resulting in the second uplink modulation signal of the fourth UE 114 causing degradation to the other uplink modulation signals of the first, second and third UEs 111-113 due to inter-carrier interference. Further, the second uplink modulation signal of the fourth UE 114 may also be degraded due to inter-symbol interference or inter-carrier interference. Instead, the fourth UE 114 may use the first uplink modulation signal to adjust for a larger timing advance that is supported by the first uplink modulation signal but not the second uplink modulation signal. In addition, the fifth UE 115 is shadowed by a first structure 121. A primary propagation path of an uplink transmission by the fifth UE 115 is reflected by a second structure 123 to the base station 101. Due to a length of the primary propagation path between the fifth UE 115 and the base station 101 , if the fifth UE 115 uses the second uplink modulation signal, then the orthogonality between the second uplink modulation signal transmitted by the fifth UE 115 and the other uplink modulation signals transmitted by the first, second, third and fourth UEs 111-114 may be lost. Instead, the fifth UE 115 may use the first uplink modulation signal to adjust for a larger timing advance that is supported by the first uplink modulation signal but not the second uplink modulation signal.

FIG. 2 shows uplink modulation signals 201-204 transmitted by UEs and received at a base station in a communication system that does not use timing advance. Each of the uplink modulation signals 201-104 may include two modulation symbols as shown in FIG. 2. In one example, each modulation symbol may be an OFDM modulation symbol or the like. Each modulation symbol may have a modulation symbol duration 211 that includes a CP and data. In FIG. 2, the uplink modulation signal 202 from the second UE arrives at the base station with the largest delay, whereas the uplink modulation signal 203 from the third UE arrives at the base station with the shortest delay. The largest delay is due to a primary propagation path from the second UE to the base station being the longest and the smallest delay is due to a primary propagation path from the third UE to the base station being the shortest. Each uplink modulation signal 201-204 may be time aligned so that the uplink modulation signals 201-204 transmitted by each UE arrive at the serving base station around the same time, such as within a CP interval of a first symbol of each uplink modulation signal 201-204. When the uplink modulation signals 201-204 arrive within the CP interval, their mutual orthogonality may be preserved. Thus, the timing advance needed for each UE may be estimated at the serving base station based on the random access signal from each UE. The base station may then inform each UE of a level of timing advance needed so that any subsequent signals (e.g. uplink shared channel signal) transmitted by the UE may arrive at the base station within the cyclic prefix interval.

FIG. 3 shows uplink modulation signals 301-304 transmitted by UEs and received at a base station in a communication system that uses timing advance. In FIG. 3, a timing advance of the uplink modulation signal 301 of the first UE is correct, whereas a timing advance for each of the uplink modulation signals 302-303 of the second and third UEs, respectively, is incorrect. However, for the second UE and the third UE, although each of their timing advances is incorrect, the error in each of their timing advances is no more than about a CP interval 313 of a first modulation symbol of the uplink modulation signal 301. For the fourth UE, an estimate of a timing advance of the uplink modulation signal 304 is substantially incorrect, and the error is greater than the CP interval 313 of the first modulation symbol of the uplink modulation signal 301.

In FIG. 3, each of the uplink modulation signals 301-304 may include one or more modulation symbols. For example, each of the uplink modulation signals 301-304 may include two modulation symbols. Each modulation symbol may have a symbol duration 311 that includes a CP and data. A receiver of a base station may receive a combined signal that includes a combination of the uplink modulation signals 301-304 transmitted by the first, second, third and fourth UEs, respectively. In demodulating the second symbol for each of the UEs, the receiver may discard the CP portion of the modulation symbol and may use a portion of the combined signal 315 for demodulation. The portion of the combined signal 315 used for demodulation may include cyclic shifts of the second symbol of the uplink modulation signals 301-303 of the first, second and third UEs. Since these are cyclic shifts of the orthogonal modulation symbols, the orthogonality may be preserved. However, the portion of the combined signal 315 used for demodulation may also include a first modulation symbol and a second modulation symbol of the uplink modulation signal 304 of the fourth UE, which may not be a cyclic shift of either the first modulation symbol or the second modulation symbol of the fourth UE. The orthogonality between the uplink modulation signal 304 of the fourth UE and the other uplink modulation signals 301-303 of the first, second and third UEs, respectively, may be lost. Hence, the uplink modulation signal 304 of the fourth UE may cause degradation to the other uplink modulation signals 301-303, respectively, due, for instance, to inter-carrier interference. Also, the uplink modulation signal 304 of the fourth UE may also be degraded due, for instance, to inter-symbol interference or inter-carrier interference.

FIG. 4 illustrates one embodiment of a system 400 of performing data transmission and reception in a communication system in accordance with various aspects as described herein. In FIG. 4, a first uplink modulation signal 411 is represented. The UE may generate the first uplink modulation signal 411 by repeating each modulation symbol 403-409 one or more times. For example, a modulation symbol 403 may be repeated six times to obtain repeated

modulation symbols 415-420, as shown. Further, a first CP 413 may be inserted into or appended to the repeated first modulation symbols 415-420 to obtain the first uplink modulation signal 411. For example, the first CP 405 may be appended prior to the repeated modulation symbols 415-420, as shown. Also, a guard period 403 may be appended prior to the first CP 403 to obtain the first uplink modulation signal 411. A slot 401 may include seven modulation symbols 403-409.

FIG. 5 illustrates another embodiment of a system 500 of performing data transmission and reception in a communication system in accordance with various aspects as described herein. In FIG. 5, a first uplink modulation signal 511 may be generated and transmitted by a first UE. A receiver of a base station may receive a combined signal that includes the first uplink modulation signal 511 with a timing advance that is correct. The first uplink modulation signal 511 may include multiple modulation symbols 503-509. Further, a slot 501 may include the multiple modulation symbols 503-509. The receiver of the base station may apply receiver processing to the combined signal such as discarding a CP of a first modulation symbol 503, taking the next samples as data of the first modulation symbol 503, discarding a CP of a second modulation symbol 504, taking the next samples as data of the second modulation symbol 504, and repeating this process for the remaining modulation symbols 505-509.

In FIG. 5, the data of the first modulation symbol 503 may not have any contribution from the first uplink modulation signal 511 , as shown, since it is in a guard period 513 of the first uplink modulation signal 511. It may however include uplink modulation signals from other UEs. The data of the second modulation symbol 504 may include a contribution from the first uplink modulation signal 511 , starting with a segment 531 to a segment 532. This portion is a cyclic shift of the repeated data, and thus the orthogonality with all other UEs may be preserved. The data portion of the third modulation symbol 505 may include a contribution from the first uplink modulation signal 511 , starting with a segment 533 to a segment 534. Again, this data portion may be a cyclic shift of the repeated data, and thus the orthogonality with all other UEs may be preserved. The data portion of the third modulation symbol 505 may be a cyclic shift of the data portion of the second modulation symbol. This means that effective channel coefficient in the frequency-domain may need to be phase rotated according to the relative time shift. Thus, in order to combine these modulation symbols coherently, a suitable phase shift may need to be applied. This same process may be applied to the remaining modulation symbols in the slot 501.

FIG. 6 illustrates another embodiment of a system 600 of performing data transmission and reception in a communication system in accordance with various aspects as described herein. In FIG. 6, a first uplink modulation signal 611 may be generated and transmitted by a first UE. A receiver of a base station may receive a combined signal that includes the first uplink modulation signal 611 with a timing advance that is incorrect. In this example, a timing advance error of the first uplink modulation signal 611 is larger (e.g., about 60 samples). The receiver of the base station may apply a same process to the combined signal as previously described, i.e., discarding a CP of a first modulation symbol, taking data of the first modulation symbol, discarding a CP of a second modulation symbol, taking data of the second modulation symbol, discarding a CP of a third modulation symbol, taking data of the third modulation symbol, and repeating this process for the remaining modulation symbols. Due to the larger timing advance, the first uplink modulation signal 611 may cause interference to the first modulation symbol 603 and the seventh modulation symbol 609 of the second uplink

modulation signal 601 transmitted by the second UE as well as any other uplink modulation signals transmitted by other UEs. However, the second modulation symbol 604 to the sixth modulation symbol 608 may maintain orthogonality with the second modulation symbol to the sixth modulation symbol of the second uplink modulation signal 601 of the second UE as well as the uplink modulation signals transmitted by other UEs. Furthermore, the receiver of the base station may need to apply phase shifting to the different repetitions of the first uplink modulation signal 611 in order to coherently combine them.

FIG. 7 illustrates one embodiment of a repetition pattern 700 of data symbols 701-704 and pilot symbols 705-706 in a communication system in accordance with various aspects as described herein. In order to perform channel estimation and to preserve orthogonality between the pilot symbols having the format of the first uplink modulation signal 411 (as shown in FIG. 4) and uplink modulation signals by other UEs, the same (or similar) repetition pattern as shown in FIG. 7 may be applied to the pilot signals 705-706. FIG. 7 provides an example of multiplexing data symbols and pilot symbols. For instance, for every N data symbols 701-704, the pilot symbol 705-706 may be inserted with each data symbol 701-704 and each pilot symbol 705-706 using a format of the first uplink modulation signal 411.

FIG. 8 shows another embodiment of a system 800 for performing data reception in a communication system in accordance with various aspects as described herein. In FIG. 8, the system 800 may be configured to include demodulators 801 a-801 n, phase rotators 803a-803n, channel compensators 805a-805n, a combiner 807, and a channel estimator 809. Each of the demodulators 801a-801 n may receive a modulation symbol from the first uplink modulation signal 411 as input and may discard a CP of the modulation symbol and may take the next samples as data of the modulation symbol. The data of the first modulation symbol may not have any contribution from the first uplink modulation signal 411 , since it is in a guard period of the first uplink modulation signal 411. It may however include uplink modulation signals from other UEs. The data of the second modulation symbol may include a contribution from the first uplink modulation signal 411. This portion is a cyclic shift of repeated data of the original modulation symbol, and thus the orthogonality with all other UEs may be preserved. The data portion of the third modulation symbol may include a contribution from the first uplink modulation signal 411. Again, this data portion may be a cyclic shift of the repeated data of the original modulation symbol, and thus the orthogonality with all other UEs may be preserved. Further, the data portion of the third modulation symbol may be a cyclic shift of the data portion of the second modulation symbol. This means that effective channel coefficient in the frequency- domain may need to be phase rotated according to the relative time shift. Hence, the output of the demodulators 801 a-801 n that demodulate the first uplink modulation signal 411 may be referred to as phase-rotated repeated data or pilot symbols. Hence, the phase rotators 803a- 803n may phase rotate the phase-rotated repeated data or pilot symbols to obtain phase- aligned data or pilot symbols. The phase-aligned pilot symbols are input to the channel estimator 809 where they are used to determine a channel estimate. The channel estimator 809 provides the channel estimate to the channel compensator 805a-805n where it channel compensates the phase-aligned repeated data symbols to obtain channel compensated repeated data symbols. The channel compensated repeated data symbols are input to the combiner where it combines the channel compensated repeated data symbols to obtain a received data symbol.

Furthermore, this disclosure describes systems and methods for an uplink shared channel that preserves orthogonality among NB loT UEs, including when an estimate of the timing advance is poor. This uplink shared channel structure may also maintain orthogonality with LTE when NB loT is deployed inside an LTE carrier, including using resource blocks within a normal LTE carrier or unused resource blocks within a guard-band of an LTE carrier.

The uplink shared channel may improve coexistence performance with LTE when NB loT is deployed inside an LTE carrier or in the guard band of an LTE carrier. Further, the uplink shared channel may improve coexistence performance with LTE without having to increase the accuracy of an estimated timing advance. This allows the timing advance to be estimated based on a narrow bandwidth random access signal that has close to zero decibels (0 dB) PAPR and has other characteristics that may reduce the cost of a UE.

Uplink LTE uses SC-FDMA, which is essentially precoded orthogonal frequency-division multiple-access (OFDMA). In one exemplary embodiment, each of the uplink modulation signals may include two OFDM symbols. Each OFDM symbol may have an OFDM system duration that includes a CP and data. The uplink modulation signal from a second UE may arrive at a serving base station with the largest delay, whereas the uplink modulation signal from a third UE signal may arrive at the serving base station with the shortest delay. This is due to the second UE being the furthest UE of away from the serving base station and the third UE being the closest UE to the serving base station. For OFDMA signals, it is desired to align the uplink modulation signals transmitted by the UEs served by the base station so that the uplink modulation signals arrive at the base station around the same time, such as within a cyclic prefix interval. When the uplink modulation signals transmitted by the UEs arrive within the CP interval, their mutual orthogonality may be preserved. Thus, in LTE, the timing advance needed for each UE may be estimated at the serving base station based on the random access signal from each UE. The base station may then inform each UE of a level of timing advance needed so that any subsequent signals (e.g. uplink shared channel signal) transmitted by the UE may arrive at the base station within the cyclic prefix. The estimate of the timing advance may not be accurate.

In another exemplary embodiment, a timing advance for a first UE is correct, whereas a timing advance for each of the other UEs is incorrect. However, for a second UE and a third UE, although each of their timing advances is incorrect, the error in each of their timing advance is no more than about one CP interval. For a fourth UE, an estimate of a timing advance is substantially incorrect, and the error is greater than the one CP interval. The fourth UE may be in a poor coverage area. Each of the uplink modulation signals may include one or more OFDM symbols such as two OFDM symbols. Each OFDM symbol may have an OFDM system duration that includes a CP and data. A receiver of a serving base station may receive a combined signal that includes a combination of uplink modulation signals transmitted by the other UEs. In demodulating the second symbol of each uplink modulation signal, the receiver may discard a CP portion of the OFDM symbol and may use a portion of the combined signal for demodulation. The portion of the combined signal used for demodulation may include cyclic shifts of the second symbols of the first, second, third and fourth UEs. Since these are all cyclic shifts of the orthogonal OFDM symbols, the orthogonality may be preserved. However, the portion of the combined signal used for demodulation may also include a first OFDM symbol and a second OFDM symbol of the fourth UE, which may not be a cyclic shift of either the first OFDM symbol or the second OFDM symbol of the fourth UE. The orthogonality between the uplink modulation signal of the fourth UE and the other uplink modulation signals of the other UEs may be lost. Hence, the uplink modulation signal of the fourth UE may cause degradation to the other uplink modulation signals of the other UEs due, for instance, to inter-carrier interference or the like. Also, the uplink modulation signal of the fourth UE may also be degraded due to inter-symbol interference, inter-carrier interference or the like.

In another exemplary embodiment, an LTE slot may include seven OFDM symbols. Each OFDM symbol may include a CP and data. In one example, for a sampling rate of 1.92 MHz, the data of each OFDM symbol may be one hundred and twenty-eight (128) samples and the CP of the first OFDM symbol may be ten (10) samples and the CP for each of the other

OFDM symbols may be nine (9) samples. For a UE with a substantial timing advance error, the UE may generate an uplink modulation signal that includes each OFDM symbol repeated a number of times. For example, a first OFDM symbol may be repeated six times to obtain repeated first OFDM symbols. Further, an elongated CP may be inserted into or appended to the repeated first OFDM symbols to obtain the uplink modulation signal. For example, the elongated CP may be appended to the repeated symbols. Further, the elongated CP may be fifty-four (54) samples, as opposed to nine (9) or ten (10) samples for each OFDM symbol of the LTE slot. Also, a guard period may be appended prior to the elongated CP to obtain the uplink modulation signal. In one example, the guard period may be one hundred and thirty-eight (138) samples. For a UE that has a timing advance error of less than about one CP duration, typical LTE uplink transmission processing may be applied, e.g. nine (9) or ten (10) samples for the CP and one hundred and twenty-eight (128) samples for the data of each OFDM symbol.

In another exemplary embodiment, an uplink modulation signal may be generated and transmitted by a UE and may be received by a receiver of a base station with a timing advance that is correct. The receiver of the base station may apply typical LTE receiver processing, i.e. discarding the first ten (10) samples as the CP of a first OFDM symbol, taking the next one hundred and twenty-eight (128) samples as the data of the first OFDM symbol, discarding the next nine (9) samples of a second OFDM symbol, taking the next one hundred and twenty-eight (128) samples as the data of the second OFDM symbol, etc. The data of the first OFDM symbol may not have any contribution from the uplink modulation signal, since it is in a guard period of the uplink modulation signal. It may however include uplink modulation signals from other UEs. The data of the second OFDM symbol may include a contribution from the uplink modulation signal. This portion is a cyclic shift of the original version, and thus the orthogonality with all other UEs may be preserved. The data portion of the third OFDM symbol consists of a contribution from the uplink modulation signal. Again, this portion is a cyclic shift of the original version, and thus the orthogonality with all other UEs is preserved. The data portion of the third OFDM symbol is a cyclic shift of the data portion of the second OFDM symbol. This means that effective channel coefficient in the frequency-domain needs to be phase rotated according to the relative time shift. Thus, in order to combine these OFDM symbols coherently, a suitable phase shift needs to be applied. Without going into much further details, it may be seen that the above description applies to all the remaining OFDM symbols in the slot.

In another exemplary embodiment, a timing advance error for a first uplink modulation signal transmitted by a first UE is large such as sixty (60) samples. A receiver of a base station may still follow the same process as previously described (i.e. discarding the first 10 samples, taking the next 128 samples as the data portion of the first OFDM symbol, discarding the next 9 samples, taking the next 128 samples as the data portion of the second OFDM symbol, discarding the next 9 samples, taking the next 128 samples as the data portion of the third OFDM symbol, etc.). Since the timing advance of the first uplink modulation signal is large, the first uplink modulation signal may cause interference to a first OFDM symbol and a seventh OFDM symbol of a second uplink modulation signal transmitted by a second UE. However, the second OFDM symbol to the sixty OFDM symbol may maintain orthogonality with other uplink modulation signals transmitted by other UEs. Furthermore, as previously described, the receiver of the base station may need to apply suitable phase shifts in order to be able to combine different repetitions of the UE signal coherently.

In order to perform channel estimation and also preserve orthogonality between the pilot symbols of this special UE signal and all the other UE signals, the same (or similar) repetition pattern as shown in FIG. 4 needs to be applied to the pilot signal. An example of data and pilot symbols multiplexing is shown in FIG. 7. For every N data slots, a pilot slot is inserted, and each data and pilot slot follows the format of FIG. 4.

An example channel estimation process is shown in FIG. 9. A key step shown here is that the phase rotation due to the different cyclic shifts of different repetitions is removed before performing channel estimation based on multiple pilot symbols. Example data symbol receiver processing operations based on either coherent combining of symbol estimates or non-coherent combining of log-likelihood ratios (or soft-bits) are shown in FIG. 10 and FIG. 11 , respectively. Again, a key step is to apply an appropriate phase rotation to account for the unique cyclic shift of each repetition. The receiver may further consider the possibility that repetition #6 in FIG. 6 is not a full symbol and is subject to interference due to poor timing advance. The receive may weight down such a repetition in the coherent combining process to account for that this may be a less reliable repetition compared to others.

In LTE, the subcarrier spacing is 15 kHz and the transmission scheme as illustrated in

FIG. 4 is according to the 15 kHz subcarrier spacing numerology (e.g. CP duration, data portion duration, OFDM symbol duration).

The transmission scheme shown in FIG. 4 for UEs with poor timing advance accuracy may also be viewed as generating a signal based on 2.5 kHz subcarrier spacing numerology. With 2.5 kHz subcarrier spacing, the CP may be 54-sample long (at the same 1.92 MHz sampling rate as discussed earlier), and the data portion may be 768-sample long. That is the CP and data portions may be 6 times long compared to those of 15 kHz subcarrier spacing. The signal illustrated in FIG. 4 is indeed one OFDM symbol according to the 2.5 kHz

numerology. However, not any signal with 2.5 kHz numerology achieves good orthogonality with signals based on 15 kHz numerology. Both 2.5 kHz and 15 kHz subcarrier grids are shown in FIG. 12. As shown, a number of subcarriers on the 2.5 kHz grids fall also on the 15 kHz grids. These subcarriers are represented by green dashed arrows. According to this disclosure, only one of these special 2.5 kHz subcarriers may be used for UEs with poor timing advance accuracy. Furthermore, a guard time is introduced to alleviate the mutual interference between UEs using special "2.5 kHz" subcarrier and UEs using the other regular 15 kHz subcarriers.

FIG. 13 shows one embodiment of a method 1300 of performing data transmission in a communication system in accordance with various aspects as described herein. In FIG. 13, the method 1300 may start, for instance, at block 1301 where it may include generating, by a wireless device in a communication system, a transmit signal that represents a block of user or pilot data. The transmit signal may include: (1) a guard period excluding any of the user or pilot data in the block, (2) after the guard period, a cyclic prefix formed from a tail end portion of the block of user or pilot data, and (3) after the cyclic prefix, multiple contiguous repetitions of the block of user or pilot data. At block 1303, the method 1300 may include obtaining the tail end portion of the block of user or pilot data as comprising a sub-block that has a defined length and that is positioned at a tail end of the block of user or pilot data. Further, the defined length may be an integer multiple of a number of the contiguous repetitions of the block of user or pilot data in the transmit signal. At block 1305, the method 1300 may also include forming the cyclic prefix from the tail end portion of the block of user or pilot data. At block 1307, the method 1300 may include transmitting, by the wireless device, to a base station, the generated transmit signal. FIG. 14 shows another embodiment of a method 1400 of performing data reception in a communication system in accordance with various aspects as described herein. In FIG. 14, the method 1400 may start, for instance, at block 1401 where it may include receiving, by a base station in a communication system, from a wireless device, a receive signal that represents a block of user or pilot data, wherein the receive signal includes: (1) a guard period excluding any of the user or pilot data in the block, (2) after the guard period, a cyclic prefix formed from a tail end portion of the block of user or pilot data, and (3) after the cyclic prefix, multiple contiguous repetitions of the block of user or pilot data. At block 1403, the method 1400 may include removing any portion of the receive signal that was received prior to the cyclic prefix. At block 1405, the method 1400 may further include extracting the block of user or pilot data from the receive signal. At block 1407, the method 1400 may include demodulating the received signal.

FIG. 15 shows another embodiment of a method 1500 of performing data transmission in accordance with various aspects as described herein. In FIG. 15, the method 1500 may start, for instance, at block 1501 where it may include receiving, by a base station, from a first wireless device, a first uplink modulation signal having a plurality of contiguous modulation symbols. An initial modulation symbol of the plurality of contiguous modulation symbols may include at least a portion of a guard period. Further, each of a remaining contiguous modulation symbols may include at least a portion of a phase-rotated repeated user or pilot data of a certain modulation symbol. Also, each of the remaining contiguous modulation symbols may include a progressively different phase rotation of the repeated user or pilot data of the certain modulation symbol. In addition, at least one of the initial modulation symbol and an adjacent modulation symbol of the plurality of contiguous modulation symbols may include at least a portion of a first cyclic prefix. At block 1503, the method 1500 may include demodulating the remaining contiguous portion of the plurality of contiguous modulation symbols of the first uplink modulation signal to obtain the plurality of phase-rotated repeated user or pilot data. At block 1505, the method 1500 may include phase rotating each of the plurality of phase-rotated repeated user or pilot data to obtain a plurality of phase-aligned repeated user or pilot data. At block 1507, the method 1500 may include determining a channel estimate using the plurality of phase-aligned repeated user or pilot data responsive to determining that the plurality of phase- aligned repeated user or pilot data is associated with a pilot symbol. At block 1509, the method 1500 may include channel compensating the plurality of phase-aligned repeated user or pilot data using a channel estimate to obtain a plurality of channel-compensated repeated user or pilot data. At block 1511 , the method 1500 may include combining the plurality of channel- compensated repeated user or pilot data to obtain a user or pilot symbol.

FIG. 16 illustrates one embodiment of a wireless device 1600 in accordance with various aspects as described herein. In some instances, the wireless device 1600 may be referred as a network node, a base station (BS), an access point (AP), a user equipment (UE), a mobile station (MS), a terminal, a cellular phone, a cellular handset, a personal digital assistant (PDA), a smartphone, a wireless phone, an organizer, a handheld computer, a desktop computer, a laptop computer, a tablet computer, a set-top box, a television, an appliance, a game device, a medical device, a display device, a metering device, or some other like terminology. In other instances, the wireless device 1600 may be a set of hardware components. In FIG. 16, the wireless device 1600 may be configured to include a processor 1601 (i.e., a processing circuit) that is operatively coupled to an input/output interface 1605, a radio frequency (RF) interface 1609, a network connection interface 1611 , a memory 1615 including a random access memory (RAM) 1617, a read only memory (ROM) 1619, a storage medium 1621 or the like, a communication subsystem 1631 , a power source 1633, another component, or any combination thereof. The storage medium 1621 may include an operating system 1623, an application program 1625, data 1627, or the like. Specific devices may utilize all of the components shown in FIG. 16, or only a subset of the components, and levels of integration may vary from device to device. Further, specific devices may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc. For instance, a computing device may be configured to include a processor and a memory.

In FIG. 16, the processor 1601 may be configured to process computer instructions and data. The processor 1601 may be configured as any sequential state machine operative to execute machine instructions stored as machine-readable computer programs in the memory, such as one or more hardware-implemented state machines (e.g., in discrete logic, FPGA, ASIC, etc.); programmable logic together with appropriate firmware; one or more stored- program, general-purpose processors, such as a microprocessor or Digital Signal Processor (DSP), together with appropriate software; or any combination of the above. For example, the processor 1601 may include two computer processors. In one definition, data is information in a form suitable for use by a computer. It is important to note that a person having ordinary skill in the art will recognize that the subject matter of this disclosure may be implemented using various operating systems or combinations of operating systems.

In the current embodiment, the input/output interface 1605 may be configured to provide a communication interface to an input device, output device, or input and output device. The wireless device 1600 may be configured to use an output device via the input/output interface 1605. A person of ordinary skill will recognize that an output device may use the same type of interface port as an input device. For example, a USB port may be used to provide input to and output from the wireless device 1600. The output device may be a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. The wireless device 1600 may be configured to use an input device via the input/output interface 1605 to allow a user to capture information into the wireless device 1600. The input device may include a mouse, a trackball, a directional pad, a trackpad, a presence-sensitive input device, a display such as a presence-sensitive display, a scroll wheel, a digital camera, a digital video camera, a web camera, a microphone, a sensor, a smartcard, and the like. The presence-sensitive input device may include a digital camera, a digital video camera, a web camera, a microphone, a sensor, or the like to sense input from a user. The presence-sensitive input device may be combined with the display to form a presence-sensitive display. Further, the presence-sensitive input device may be coupled to the processor. The sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, another like sensor, or any combination thereof. For example, the input device may be an accelerometer, a magnetometer, a digital camera, a microphone, and an optical sensor.

In FIG. 16, the RF interface 1609 may be configured to provide a communication interface to RF components such as a transmitter, a receiver, and an antenna. The network connection interface 1611 may be configured to provide a communication interface to a network 1643a. The network 1643a may encompass wired and wireless communication networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, the network 1643a may be a Wi-Fi network. The network connection interface 1611 may be configured to include a receiver and a transmitter interface used to communicate with one or more other nodes over a communication network according to one or more

communication protocols known in the art or that may be developed, such as Ethernet, TCP/IP, SONET, ATM, or the like. The network connection interface 1611 may implement receiver and transmitter functionality appropriate to the communication network links (e.g., optical, electrical, and the like). The transmitter and receiver functions may share circuit components, software or firmware, or alternatively may be implemented separately.

In this embodiment, the RAM 1617 may be configured to interface via the bus 1602 to the processor 1601 to provide storage or caching of data or computer instructions during the execution of software programs such as the operating system, application programs, and device drivers. In one example, the wireless device 1600 may include at least one hundred and twenty-eight megabytes (128 Mbytes) of RAM. The ROM 1619 may be configured to provide computer instructions or data to the processor 1601. For example, the ROM 1619 may be configured to be invariant low-level system code or data for basic system functions such as basic input and output (I/O), startup, or reception of keystrokes from a keyboard that are stored in a non-volatile memory. The storage medium 1621 may be configured to include memory such as RAM, ROM, programmable read-only memory (PROM), erasable programmable readonly memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, floppy disks, hard disks, removable cartridges, flash drives. In one example, the storage medium 1621 may be configured to include an operating system 1623, an application program 1625 such as a web browser application, a widget or gadget engine or another application, and a data file 1627. In FIG. 16, the processor 1601 may be configured to communicate with a network 1643b using the communication subsystem 1631. The network 1643a and the network 1643b may be the same network or networks or different network or networks. The communication subsystem 1631 may be configured to include one or more transceivers used to communicate with the network 1643b. For example, the communication subsystem 1631 may be configured to include one or more transceivers used to communicate with one or more remote transceivers of another wireless device such as a base station of a radio access network (RAN) according to one or more communication protocols known in the art or that may be developed, such as IEEE 802.XX, CDMA, WCDMA, GSM, LTE, UTRAN, WiMax, or the like.

In another example, the communication subsystem 1631 may be configured to include one or more transceivers used to communicate with one or more remote transceivers of another wireless device such as user equipment according to one or more communication protocols known in the art or that may be developed, such as IEEE 802.xx, CDMA, WCDMA, GSM, LTE, UTRAN, WiMax, or the like. Each transceiver may include a transmitter 1633 or a receiver 1635 to implement transmitter or receiver functionality, respectively, appropriate to the RAN links

(e.g., frequency allocations and the like). Further, the transmitter 1633 and the receiver 1635 of each transceiver may share circuit components, software or firmware, or alternatively may be implemented separately.

In the current embodiment, the communication functions of the communication subsystem 1631 may include data communication, voice communication, multimedia

communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. For example, the communication subsystem 1631 may include cellular communication, Wi-Fi communication, Bluetooth communication, and GPS communication. The network 1643b may encompass wired and wireless communication networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, the network 1643b may be a cellular network, a W-Fi network, and a near-field network. The power source 1613 may be configured to provide an alternating current (AC) or direct current (DC) power to components of the wireless device 1600.

In FIG. 16, the storage medium 1621 may be configured to include a number of physical drive units, such as a redundant array of independent disks (RAID), a floppy disk drive, a flash memory, a USB flash drive, an external hard disk drive, thumb drive, pen drive, key drive, a high-density digital versatile disc (HD-DVD) optical disc drive, an internal hard disk drive, a Blu- Ray optical disc drive, a holographic digital data storage (HDDS) optical disc drive, an external mini-dual in-line memory module (DIMM) synchronous dynamic random access memory (SDRAM), an external micro- DIMM SDRAM, a smartcard memory such as a subscriber identity module or a removable user identity (SIM/RUIM) module, other memory, or any combination thereof. The storage medium 1621 may allow the wireless device 1600 to access computer- executable instructions, application programs or the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied in storage medium 1621 , which may comprise a computer-readable medium.

The functionality of the methods described herein may be implemented in one of the components of the wireless device 1600 or partitioned across multiple components of the wireless device 1600. Further, the functionality of the methods described herein may be implemented in any combination of hardware, software or firmware. In one example, the communication subsystem 1631 may be configured to include any of the components described herein. Further, the processor 1601 may be configured to communicate with any of such components over the bus 1602. In another example, any of such components may be represented by program instructions stored in memory that when executed by the processor 1601 performs the corresponding functions described herein. In another example, the functionality of any of such components may be partitioned between the processor 1601 and the communication subsystem 1631. In another example, the non-computative-intensive functions of any of such components may be implemented in software or firmware and the computative- intensive functions may be implemented in hardware.

FIGs. 17A-B show other embodiments of a wireless device 1700a-b in accordance with various aspects as described herein. In FIG. 17A, the wireless device 1700a (e.g., radio node, UE, or the like) may include processing circuitry 1701 a and radio frequency (RF) communication circuitry 1705a. The RF circuitry 1705a may be configured to transmit and/or receive information to and/or from one or more other nodes, e.g., via any communication technology. Such communication may occur via one or more antennas 1707a that are either internal or external to the wireless device 1700a. The processing circuitry 1701 a may be configured to perform processing described above (e.g., the method 1300 in FIG. 13, such as by executing instructions stored in memory 1703a). The processing circuitry 1701 a in this regard may implement certain functional means, units, or modules.

In FIG. 17B, the wireless device 1700b may implement various functional means, units, or modules (e.g., via the processing circuitry 1701a in FIG. 17A and/or via software code). These functional means, units, or modules (e.g., for implementing the method 1300 in FIG. 13) may include a generating unit or module 1711 b for generating a transmit signal that represents a block of data. Further, the transmit signal may include: (1) a guard period excluding any of the data in the block, (2) after the guard period, a cyclic prefix formed from a tail end portion of the block of data, and (3) after the cyclic prefix, multiple contiguous repetitions of the block of data. In addition, these functional means, units, or modules may include a transmitting unit or module 1713b for transmitting, to a base station, the generated transmit signal.

FIG. 17C shows one embodiment of a user equipment 1700c in accordance with various aspects as described herein. In FIG. 17C, the user equipment 1700c may include processing circuitry 1701c and RF communications circuitry 1705c. The RF circuitry 1705c may be configured to transmit and/or receive information to and/or from one or more other base stations, e.g., via any communication technology. Such communication may occur via one or more antennas 1707c that are either internal or external to the user equipment 1700c. The processing circuitry 1701c may be configured to perform processing described above (e.g., the method 1300 in FIG. 13, such as by executing instructions stored in memory 1703c). The processing circuitry 1701c in this regard may implement certain functional means, units, or modules.

FIGs. 18A-B show other embodiments of a network node 1800a-b in accordance with various aspects as described herein. In FIG. 18A, the network node 1800a (e.g., radio network node, base station, or the like) may include processing circuitry 1801 a and RF communication circuitry 1805a. The RF circuitry 1805a may be configured to transmit and/or receive information to and/or from one or more other nodes, e.g., via any communication technology. Such communication may occur via one or more antennas 1807a that are either internal or external to the network node 1800a. The processing circuitry 1801 a may be configured to perform processing described above (e.g., the methods 1400 and 1500 in respective FIGs. 14 and 15, such as by executing instructions stored in memory 1803a). The processing circuitry 1801 a in this regard may implement certain functional means, units, or modules.

In FIG. 18B, the wireless device 1800b may implement various functional means, units, or modules (e.g., via the processing circuitry 1801a in FIG. 18A and/or via software code). These functional means, units, or modules (e.g., for implementing the methods 1400 and 1500 in respective FIGs. 14 and 15) may include a receiving unit or module 1811 b for receiving, from a wireless device, a receive signal that represents the block of data. Further, the receive signal may include: (1) a guard period excluding any of the data in the block, (2) after the guard period, a cyclic prefix formed from a tail end portion of the block of data, and (3) after the cyclic prefix, multiple contiguous repetitions of the block of data. In addition, these functional means, units, or modules may include a demodulating unit or module 1813b for demodulating the received signal. The demodulating unit or module 1813b may be configured to include one or more sub-blocks. For instance, the demodulating unit or module 1813b may be configured to include a phase rotating unit or module 1815b, a channel estimating unit or module 1817b, a channel compensating unit or module 1819b, a combining module 1821 b, the like, or any combination thereof. In the current embodiment, these functional means, units, or modules may include the phase rotating unit or module 1815b for phase rotating each of the plurality of phase-rotated repeated data to obtain a plurality of phase-aligned repeated data. Further, these functional means, units, or modules may include the channel estimating unit or module 1817b for determining a channel estimate using the plurality of phase-aligned repeated data responsive to determining that the plurality of phase-aligned repeated data is associated with a pilot symbol. Also, these functional means, units, or modules may include the channel compensating unit or module 1819b channel compensating the plurality of phase-aligned repeated data using a channel estimate to obtain a plurality of channel-compensated repeated data. In addition, these functional means, units, or modules may include the combining module 1821 b for combining the plurality of channel-compensated repeated data to obtain a data symbol.

FIG. 18C shows one embodiment of a base station 1800c in accordance with various aspects as described herein. In FIG. 18C, the base station 1800c may include processing circuitry 1801c and RF communication circuitry 1805c. The RF circuitry 1805c may be configured to transmit and/or receive information to and/or from one or more user equipment, e.g., via any communication technology. Such communication may occur via one or more antennas 1807a that are either internal or external to the base station 1800c. The processing circuitry 1801c may be configured to perform processing described above (e.g., the methods 1400 and 1500 in respective FIGs. 14 and 15, such as by executing instructions stored in memory 1803a). The processing circuitry 1801c in this regard may implement certain functional means, units, or modules.

In one exemplary embodiment, a method may be implemented by a radio node for transmitting a block of data in a communication system. The method may include generating a transmit signal that represents the block of data. The transmit signal may include: (1) a guard period excluding any of the data in the block, (2) after the guard period, a cyclic prefix formed from a tail end portion of the block of data, and (3) after the cyclic prefix, multiple contiguous repetitions of the block of data. Further, the method may include transmitting the generated transmit signal.

In another exemplary embodiment, the method may include obtaining the tail end portion of the block of data as comprising a sub-block that has a defined length and that is positioned at a tail end of the block of data. Further, the defined length may be an integer multiple of the number of the contiguous repetitions of the block of data in the transmit signal. The method may also include forming the cyclic prefix from the tail end portion of the block of data.

In another exemplary embodiment, the method may include forming the cyclic prefix as an extended cyclic prefix that is at least forty percent of the length of the block of data.

In another exemplary embodiment, the method may include transmitting the transmit signal at a time such that the transmit signal arrives at a receiver as comprising multiple cyclically-shifted versions of the block of data, with each version prefixed by a tail end portion of that version.

In another exemplary embodiment, the cyclically-shifted versions may cyclically shift the block of data to a different extent across the transmit signal.

In another exemplary embodiment, the cyclically-shifted versions may cyclically shift the block of data to a progressively lesser extent across the transmit signal towards an end of the transmit signal.

In another exemplary embodiment, the method may perform the generating and transmitting steps when a timing advance exceeds a defined threshold.

In another exemplary embodiment, when the timing advance is less than a defined threshold, the method may include transmitting the block of data: (1) with a shorter cyclic prefix than when the timing advance exceeds the defined threshold, (2) without said guard period, and/or (3) without said multiple repetitions.

In another exemplary embodiment, the method may include dynamically selecting between: (1) generating the transmit signal to include the guard period, cyclic prefix, and multiple contiguous repetitions, and (2) generating the transmit signal to comprise a shorter cyclic prefix intervening between each block of data within the transmit signal, the shorter cyclic prefix shorter than said cyclic prefix.

In another exemplary embodiment, the method may include selecting a length of the cyclic prefix according to a scheduling grant received from a serving base station.

In another exemplary embodiment, the transmit signal may have a subcarrier spacing of 2.5 kHz.

In another exemplary embodiment, the transmit signal may be an uplink OFDM signal.

In another exemplary embodiment, the block of data may include a block of user data. In another exemplary embodiment, the block of data may include a block of pilot data.

In another exemplary embodiment, the transmit signal may be a narrowband Internet of Things (NB-loT) signal.

In one exemplary embodiment, a radio node for transmitting a block of data in a communication system may include a generator operationally coupled to a transmitter. The generator may be configured to generate a transmit signal that represents the block of data. Further, the transmit signal may include: (1) a guard period excluding any of the data in the block, (2) after the guard period, a cyclic prefix formed from a tail end portion of the block of data, and (3) after the cyclic prefix, multiple contiguous repetitions of the block of data. The transmitter may be configured to transmit the generated transmit signal. In another exemplary embodiment, the radio node may be configured to perform any of the methods described herein.

In one exemplary embodiment, a radio node for transmitting a block of data in a communication system may include means for generating a transmit signal that represents the block of data. Further, the transmit signal may include: (1) a guard period excluding any of the data in the block, (2) after the guard period, a cyclic prefix formed from a tail end portion of the block of data, and (3) after the cyclic prefix, multiple contiguous repetitions of the block of data. Further, the radio node may include means for transmitting the generated transmit signal.

In one exemplary embodiment, a method may be implemented by a radio network node for receiving a block of data in a communication system. The method may include receiving, by the radio network node, a receive signal that represents the block of data. The receive signal may include: (1) a cyclic prefix formed from a tail end portion of the block of data, (2) after the cyclic prefix, multiple contiguous repetitions of the block of data, and (3) extracting the block of data from the received signal.

In one exemplary embodiment, a method may be implemented by a radio network node.

The method may include receiving, by the radio network node, a receive signal that comprises a sequence of OFDM symbols representing a block of data. Further, the method may include removing a head-end portion of each OFDM symbol in the sequence to obtain a sequence of OFDM symbol data portions. Also, the method may include extracting the block of data from the OFDM symbol data portions. The method may perform the extracting step including by phase rotating at least one OFDM symbol data portion based on a cyclic shift of that data portion relative to another OFDM symbol data portion. Further, the method may perform the extracting step including by combining those OFDM symbol data portions as phase rotated.

In another exemplary embodiment, the method may include determining a timing advance with which the receive signal is to be transmitted. Further, the method may include performing said receiving, removing, and extracting steps responsive to determining that the timing advance exceeds a defined threshold and signaling that the receive signal is to be transmitted with said timing advance.

In another exemplary embodiment, the method may include phase rotating by a predefined length of said head-end portion.

In another exemplary embodiment, the method may include selecting a length of a cyclic prefix that is to be used to form the receive signal for transmission by prefixing that cyclic prefix to multiple contiguous repetitions of the block of data. Further, the method may include signaling the selected length within a scheduling grant.

In one exemplary embodiment, a radio network node may be configured to receive a receive signal that comprises a sequence of OFDM symbols representing a block of data. Further, the radio network node may be configured to remove a head-end portion of each OFDM symbol in the sequence to obtain a sequence of OFDM symbol data portions. Also, the radio network node may be configured to extract the block of data from the OFDM symbol data portions. The radio network node may extract the block of data including by phase rotating at least one OFDM symbol data portion based on a cyclic shift of that data portion relative to another OFDM symbol data portion. Further, the radio network node may extract the block of data by combining those OFDM symbol data portions as phase rotated.

In another exemplary embodiment, the radio network node may be configured to perform any of the methods described herein.

In one exemplary embodiment, a method may be implemented by a base station for performing data reception in a communication system. The method may include receiving, by the base station, from a first wireless device, a first uplink modulation signal having a plurality of contiguous modulation symbols. An initial modulation symbol of the plurality of contiguous modulation symbols may include at least a portion of a guard period. Further, each of a remaining contiguous modulation symbols may include at least a portion of a phase-rotated repeated data of a certain modulation symbol. Also, each of the remaining contiguous modulation symbols may include a progressively different phase rotation of the repeated data of the certain modulation symbol. In addition, at least one of the initial modulation symbol and an adjacent modulation symbol of the plurality of contiguous modulation symbols may include at least a portion of a first cyclic prefix.

In another exemplary embodiment, the method may include receiving a combined signal that includes the first uplink modulation signal and a second uplink modulation signal transmitted by a second wireless device. The second uplink modulation signal may include a plurality of modulation symbols with each modulation symbol having a second cyclic prefix and data.

In another exemplary embodiment, a length of the first cyclic prefix may be longer than a length of the second cyclic prefix.

In another exemplary embodiment, the first uplink modulation signal may be

substantially orthogonal to the second uplink modulation signal.

In another exemplary embodiment, the certain modulation symbol may correspond to a data symbol.

In another exemplary embodiment, the certain modulation symbol may correspond to a pilot symbol.

In another exemplary embodiment, the first uplink modulation signal may be capable of a timing advance that is greater than a timing advance of the second uplink modulation signal. In another exemplary embodiment, a subcarrier spacing of the first uplink modulation signal may be equivalent to a subcarrier spacing of the second uplink modulation signal.

In another exemplary embodiment, a subcarrier spacing of the first uplink modulation signal may be less than a subcarrier spacing of the second uplink modulation signal.

In another exemplary embodiment, a subcarrier spacing of the second uplink modulation signal may be a multiple of a subcarrier spacing of the first uplink modulation signal.

In another exemplary embodiment, a subcarrier spacing of the first uplink modulation signal is 2.5 kHz and a subcarrier spacing of the second uplink modulation signal is 15 kHz.

In another exemplary embodiment, the method may include demodulating the remaining contiguous portion of the plurality of contiguous modulation symbols of the first uplink modulation signal to obtain the plurality of phase-rotated repeated data. Further, the method may include phase rotating each of the plurality of phase-rotated repeated data to obtain a plurality of phase-aligned repeated data. Also, the method may include determining a channel estimate using the plurality of phase-aligned repeated data responsive to determining that the plurality of phase-aligned repeated data is associated with a pilot symbol. The method may include channel compensating the plurality of phase-aligned repeated data using the channel estimate to obtain a plurality of channel-compensated repeated data. In addition, the method may include combining the plurality of channel-compensated repeated data to obtain a data symbol.

In another exemplary embodiment, the method may perform the combining step to include coherent combining of the plurality of channel-compensated repeated data.

In another exemplary embodiment, the method may perform the combining step to include using log-likelihood ratios.

In one exemplary embodiment, a base station for performing data reception in a communication system may include a receiver. The receiver may be configured to receive, from a first wireless device, a first uplink modulation signal having a plurality of contiguous modulation symbols. An initial modulation symbol of the plurality of contiguous modulation symbols may include at least a portion of a guard period. Further, each of a remaining contiguous modulation symbols may include at least a portion of a phase-rotated repeated data of a certain modulation symbol. Also, each of the remaining contiguous modulation symbols may include a progressively different cyclic shift of the repeated data of the certain modulation symbol. In addition, at least one of the initial modulation symbol and an adjacent modulation symbol of the plurality of contiguous modulation symbols may include at least a portion of a first cyclic prefix.

In another exemplary embodiment, the base station may be configured to include a demodulator operationally coupled to the receiver and configured to demodulate the remaining contiguous portion of the plurality of contiguous modulation symbols of the first uplink modulation signal to obtain the plurality of phase-rotated repeated data. Further, the base station may be configured to include a phase rotator operationally coupled to the demodulator and configured to phase rotate each of the plurality of phase-rotated repeated data to obtain a plurality of phase-aligned repeated data. Also, the base station may be configured to include a channel estimator operationally coupled to the phase rotator and configured to determine a channel estimate using the plurality of phase-aligned repeated data responsive to determining that the plurality of phase-aligned repeated data is associated with a pilot symbol. The base station may be configured to include a channel compensator operationally coupled to the phase rotator and configured to channel compensate the plurality of phase-aligned repeated data using the channel estimate to obtain a plurality of channel-compensated repeated data. In addition, the base station may be configured to include a combiner operationally coupled to the channel compensator and configured to combine the plurality of channel-compensated repeated data to obtain a data symbol.

In one exemplary embodiment, a base station for performing data reception in a communication system may include means for receiving, from a first wireless device, a first uplink modulation signal having a plurality of contiguous modulation symbols. An initial modulation symbol of the plurality of contiguous modulation symbols may include at least a portion of a guard period. Further, each of a remaining contiguous modulation symbols may include at least a portion of a phase-rotated repeated data of a certain modulation symbol. Also, each of the remaining contiguous modulation symbols may include a progressively different cyclic shift of the repeated data of the certain modulation symbol. In addition, at least one of the initial modulation symbol and an adjacent modulation symbol of the plurality of contiguous modulation symbols may include at least a portion of a first cyclic prefix.

In another exemplary embodiment, the base station may include means for

demodulating the remaining contiguous portion of the plurality of contiguous modulation symbols of the first uplink modulation signal to obtain the plurality of phase-rotated repeated data. Further, the base station may include means for phase rotating each of the plurality of phase-rotated repeated data to obtain a plurality of phase-aligned repeated data. The base station may include means for determining a channel estimate using the plurality of phase- aligned repeated data responsive to determining that the plurality of phase-aligned repeated data is associated with a pilot symbol. The base station may also include means for channel compensating the plurality of phase-aligned repeated data using the channel estimate to obtain a plurality of channel-compensated repeated data. In addition, the base station may include means for combining the plurality of channel-compensated repeated data to obtain a data symbol. In one exemplary embodiment, a base station for receiving a block of data in a communication system may include a receiver and a demodulator. The receiver may be configured to receive a signal that represents the block of data. The received signal may include: (1) a cyclic prefix formed from a tail end portion of the block of data, and (2) after the cyclic prefix, multiple contiguous repetitions of the block of data. The demodulator may be operationally coupled to the receiver and may be configured to demodulate the received signal.

In one exemplary embodiment, a base station for receiving a block of data in a communication system may include means for receiving a signal that represents the block of data. The received signal may include: (1) a cyclic prefix formed from a tail end portion of the block of data, and (2) after the cyclic prefix, multiple contiguous repetitions of the block of data. Further, the base station may include means for demodulating the received signal.

ABBREVIATIONS:

Abbreviation Explanation

3GPP 3^rd Generation Partnership Project

BS Base Station

CP Cyclic Prefix

DL Downlink

eNB Evolved Node B (i.e., base station)

E-UTRA Evolved Universal Terrestrial Radio Access

E-UTRAN Evolved Universal Terrestrial Radio Access Network

loT Internet of Things

LTE Long Term Evolution

MIMO Multiple Input Multiple Output

MSR Multi-Standard Radio

MTC Machine-Type Communication

NB-loT Narrow-Band Internet of Things

NB-LTE Narrow-Band LTE (e.g., 180 KHz bandwidth)

OFDM Orthogonal Frequency Division Modulation

OFDMA Orthogonal Frequency Division Modulation Access

PA Power Amplifier

PAPR Peak-to-Average Power Ratio

PRACH Physical Random Access Channel

PRB Physical Resource Block

PUSCH Physical Uplink Shared Channel

RACH Random Access Channel

RAT Radio Access Technology

RF Radio Frequency

SoC System-on-a-Chip SC-FDMA Single-Carrier, Frequency Division Multiple Access

Tx Transmitter

UE User Equipment

UL Uplink

WB-LTE Wideband LTE (i.e., corresponds to legacy LTE)

The previous detailed description is merely illustrative in nature and is not intended to limit the present disclosure, or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding field of use, background, summary, or detailed description. The present disclosure provides various examples, embodiments and the like, which may be described herein in terms of functional or logical block elements. The various aspects described herein are presented as methods, devices (or apparatus), systems, or articles of manufacture that may include a number of components, elements, members, modules, nodes, peripherals, or the like. Further, these methods, devices, systems, or articles of manufacture may include or not include additional components, elements, members, modules, nodes, peripherals, or the like.

Furthermore, the various aspects described herein may be implemented using standard programming or engineering techniques to produce software, firmware, hardware (e.g., circuits), or any combination thereof to control a computing device to implement the disclosed subject matter. It will be appreciated that some embodiments may be comprised of one or more generic or specialized processors such as microprocessors, digital signal processors, customized processors and field programmable gate arrays (FPGAs) and unique stored program

instructions (including both software and firmware) that control the one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of the methods, devices and systems described herein. Alternatively, some or all functions could be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some

combinations of certain of the functions are implemented as custom logic circuits. Of course, a combination of the two approaches may be used. Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation.

The term "article of manufacture" as used herein is intended to encompass a computer program accessible from any computing device, carrier, or media. For example, a computer- readable medium may include: a magnetic storage device such as a hard disk, a floppy disk or a magnetic strip; an optical disk such as a compact disk (CD) or digital versatile disk (DVD); a smart card; and a flash memory device such as a card, stick or key drive. Additionally, it should be appreciated that a carrier wave may be employed to carry computer-readable electronic data including those used in transmitting and receiving electronic data such as electronic mail (e- mail) or in accessing a computer network such as the Internet or a local area network (LAN). Of course, a person of ordinary skill in the art will recognize many modifications may be made to this configuration without departing from the scope or spirit of the subject matter of this disclosure.

Throughout the specification and the embodiments, the following terms take at least the meanings explicitly associated herein, unless the context clearly dictates otherwise. Relational terms such as "first" and "second," and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The term "or" is intended to mean an inclusive "or" unless specified otherwise or clear from the context to be directed to an exclusive form. Further, the terms "a," "an," and "the" are intended to mean one or more unless specified otherwise or clear from the context to be directed to a singular form. The term "include" and its various forms are intended to mean including but not limited to. References to "one

embodiment," "an embodiment," "example embodiment," "various embodiments," and other like terms indicate that the embodiments of the disclosed technology so described may include a particular function, feature, structure, or characteristic, but not every embodiment necessarily includes the particular function, feature, structure, or characteristic. Further, repeated use of the phrase "in one embodiment" does not necessarily refer to the same embodiment, although it may. The terms "substantially," "essentially," "approximately," "about" or any other version thereof, are defined as being close to as understood by one of ordinary skill in the art, and in one non-limiting embodiment the term is defined to be within 10%, in another embodiment within 5%, in another embodiment within 1 % and in another embodiment within 0.5%. A device or structure that is "configured" in a certain way is configured in at least that way, but may also be configured in ways that are not listed.

Claims

CLAIMS What is claimed is:

1. A method implemented by a wireless device for transmitting a block of user or pilot data in a communication system, the method comprising:

generating (1301) a transmit signal that represents the block of user or pilot data,

wherein the transmit signal includes:

a guard period excluding any of the user or pilot data in the block; after the guard period, a cyclic prefix formed from a tail end portion of the block of user or pilot data; and

after the cyclic prefix, multiple contiguous repetitions of the block of user or pilot data; and

transmitting (1307) the generated transmit signal.

2. The method of claim 1 , further comprising:

obtaining (1303) the tail end portion of the block of user or pilot data as comprising a sub-block that has a defined length and that is positioned at a tail end of the block of user or pilot data, wherein the defined length is an integer multiple of a number of the contiguous repetitions of the block of user or pilot data in the transmit signal; and

forming (1305) the cyclic prefix from the tail end portion of the block of user or pilot data.

3. The method of any of claims 1-2, wherein said transmitting comprises transmitting the transmit signal at a time such that the transmit signal arrives at a receiver as comprising multiple cyclically-shifted versions of the block of user or pilot data, with each version prefixed by a tail end portion of that version.

4. The method of claim 3, wherein the cyclically-shifted versions cyclically shift the block of user or pilot data to a different extent across the transmit signal.

5. The method of any of claims 3-4, wherein the cyclically-shifted versions cyclically shift the block of user or pilot data to a progressively lesser extent across the transmit signal towards an end of the transmit signal.

6. The method of any of claims 1-5, wherein said generating and transmitting are performed when a timing advance error associated with a previously generated and transmitted transmit signal exceeds a defined threshold.

7. The method of claim 6, wherein the timing advance error is estimated based on a signal strength of a signal received by the wireless device from a serving base station.

8. The method of any of claims 6-7, further comprising, when the timing advance error is less than the defined threshold, transmitting the block of user or pilot data:

with a shorter cyclic prefix than when the timing advance exceeds the defined threshold; without said guard period; and/or

without said multiple repetitions.

9. The method of any of claims 1-8, further comprising:

receiving, from a serving base station, an indication to perform said generating and

transmitting; and

wherein said generating and transmitting are responsive to the indication.

10. The method of any of claims 1-9, further comprising dynamically selecting between: generating the transmit signal to comprise the guard period, cyclic prefix, and multiple contiguous repetitions; and

generating the transmit signal to comprise a shorter cyclic prefix intervening between each block of user or pilot data within the transmit signal, the shorter cyclic prefix being shorter than said cyclic prefix.

1 1. The method of any of embodiments 1-10, further comprising selecting a length of the cyclic prefix according to a scheduling grant received from a serving base station.

12. The method of any of claims 1-11 , wherein the transmit signal has a subcarrier spacing of 3.75 kHz.

13. The method of any of claims 1-12, wherein the transmit signal is an uplink OFDM signal.

14. The method of any of claims 1-13, further comprising multiplexing the user data and the pilot data to obtain the block of user or pilot data.

15. The method of any of claims 1-14, wherein the transmit signal is a narrowband Internet of Things (NB-loT) signal.

16. The method of any of claims 1-15, further comprising encoding information to obtain the block of user or pilot data.

17. The method of any of claims 1-16, wherein said transmitting is on a physical data

18. The method of any of claims 1-17, wherein a timing advance error that corresponds to the transmitted signal is no more than the guard period.

19. The method of any of claims 1-17, wherein a timing advance error that corresponds to the transmitted signal is at least the guard period.

20. The method of any of claims 1-19, wherein the transmitted signal is associated with a contention-based, random access procedure.

21. The method of any of claims 1-20, wherein the transmitted signal excludes a preamble.

22. The method of any of claims 1-21 , wherein the wireless device is a user equipment.

23. The method of any of claims 1-22, wherein the user data includes acknowledgment (ACK) or not acknowledged (NAK) information.

24. The method of any of claims 1-23, wherein the user data includes control information.

25. A wireless device for transmitting a block of user or pilot data in a communication system, comprising:

processing circuitry (1701a, 1701 c) configured to:

generate (1301) a transmit signal that represents the block of user or pilot data, wherein the transmit signal includes:

a guard period excluding any of the user or pilot data in the block;

after the guard period, a cyclic prefix formed from a tail end portion of the block of user or pilot data; and

after the cyclic prefix, multiple contiguous repetitions of the block of pilot or user data; and

transmit (1303) the generated transmit signal.

26. The wireless device of claim 25, configured to perform the method of any of claims 2-21.

27. A method implemented by a radio network node for receiving a block of user or pilot data in a communication system, the method comprising:

receiving (1401), by the radio network node, a receive signal that represents the block of user or pilot data, wherein the receive signal comprises:

a cyclic prefix formed from a tail end portion of the block of user or pilot data; and after the cyclic prefix, multiple contiguous repetitions of the block of user or pilot data;

removing (1403) any portion of the receive signal that was received prior to the cyclic prefix; and

extracting (1405) the block of user or pilot data from the receive signal.

28. A method implemented by a radio network node, the method comprising:

receiving (1401), by the radio network node, a receive signal that comprises a sequence of OFDM symbols representing a block of user or pilot data;

removing (1403) a head-end portion of each OFDM symbol in the sequence to obtain a sequence of OFDM symbol data portions; and

extracting (1405) the block of user or pilot data from the OFDM symbol data portions, wherein said extracting comprises:

phase rotating (1505) at least one OFDM symbol data portion based on a cyclic shift of that data portion relative to another OFDM symbol data portion; and

combining (1511) those OFDM symbol data portions as phase rotated.

29. The method of claim 28, further comprising determining a timing advance with which the receive signal is to be transmitted, and performing said receiving, removing, and extracting responsive to determining that the timing advance exceeds a defined threshold and signaling that the receive signal is to be transmitted with said timing advance.

30. The method of any of claims 28-29, wherein said phase rotating comprises phase rotating by a predefined length of said head-end portion.

31. The method of any of embodiments 28-30, further comprising selecting a length of a cyclic prefix that is to be used to form the receive signal for transmission by prefixing that cyclic prefix to multiple contiguous repetitions of the block of user or pilot data, and signaling the selected length within a scheduling grant.

32. A radio network node, comprising:

processing circuitry (1801a, 1801 c) configured to:

receive (1401) a receive signal that comprises a sequence of OFDM symbols representing a block of user or pilot data;

remove (1403) a head-end portion of each OFDM symbol in the sequence to obtain a sequence of OFDM symbol data portions; and

extract (1405) the block of user or pilot data from the OFDM symbol data

portions, by:

combining (1511) those OFDM symbol data portions as phase rotated.

33. The radio network node of claim 32, configured to perform the method of any of claims 29-31.

34. A method by a base station for performing data reception in a communication system, comprising:

receiving (1501), by the base station, from a first wireless device, a first uplink

modulation signal having a plurality of contiguous modulation symbols, wherein an initial modulation symbol of the plurality of contiguous modulation symbols includes at least a portion of a guard period, each of a remaining contiguous modulation symbols includes at least a portion of a phase-rotated repeated user or pilot data of a certain modulation symbol, each of the remaining contiguous modulation symbols includes a progressively different phase rotation of the repeated user or pilot data of the certain modulation symbol, and at least one of the initial modulation symbol and an adjacent modulation symbol of the plurality of contiguous modulation symbols includes at least a portion of a first cyclic prefix.

35. The method of claim 34, wherein said receiving includes receiving a combined signal that includes the first uplink modulation signal and a second uplink modulation signal transmitted by a second wireless device, wherein the second uplink modulation signal includes a plurality of modulation symbols with each modulation symbol having a second cyclic prefix and user or pilot data.

36. The method of claim 35, wherein a length of the first cyclic prefix is longer than a length of the second cyclic prefix.

37. The method of any of claims 35-36, wherein the first uplink modulation signal is substantially orthogonal to the second uplink modulation signal.

38. The method of any of claims 35-37, wherein the first uplink modulation signal is capable of a timing advance that is greater than a timing advance of the second uplink modulation signal.

39. The method of any of claims 35-38, wherein a subcarrier spacing of the first uplink modulation signal is equivalent to a subcarrier spacing of the second uplink modulation signal.

40. The method of any of claims 35-38, wherein a subcarrier spacing of the first uplink modulation signal is less than a subcarrier spacing of the second uplink modulation signal.

41. The method of any of claims 35-40, wherein a subcarrier spacing of the first uplink modulation signal is a multiple of a subcarrier spacing of the second uplink modulation signal.

42. The method of any of claims 35-41 , wherein a subcarrier spacing of the first uplink modulation signal is 3.75 kHz and a subcarrier spacing of the second uplink modulation signal is 15 kHz.

43. The method of any of claims 34-42, wherein the user data includes acknowledgment (ACK) or not acknowledged (NAK) information.

44. The method of any of claims 34-43, wherein the user data includes control information.

45. The method of any of claims 34-44, further comprising:

demodulating (1503) the remaining contiguous portion of the plurality of contiguous

modulation symbols of the first uplink modulation signal to obtain the plurality of phase-rotated repeated user or pilot data;

phase rotating (1505) each of the plurality of phase-rotated repeated user or pilot data to obtain a plurality of phase-aligned repeated user or pilot data;

determining (1507) a channel estimate using the plurality of phase-aligned repeated user or pilot data responsive to determining that the plurality of phase-aligned repeated user or pilot data is associated with a pilot symbol;

channel compensating (1509) the plurality of phase-aligned repeated user or pilot data using the channel estimate to obtain a plurality of channel-compensated repeated user or pilot data; and

combining (1511) the plurality of channel-compensated repeated user or pilot data to obtain a user or pilot data symbol.

46. The method of claim 45, wherein combining includes coherent combining of the plurality of channel-compensated repeated data.

47. The method of any of claims 45-46, wherein combining includes using log-likelihood ratios.

48. A base station for performing data reception in a communication system, comprising: processing circuitry (1801 a, 1801 c) configured to:

receive (1501), from a first wireless device, a first uplink modulation signal having a plurality of contiguous modulation symbols, wherein an initial modulation symbol of the plurality of contiguous modulation symbols includes at least a portion of a guard period, and each of a remaining contiguous modulation symbols includes at least a portion of a phase- rotated repeated user or pilot data of a modulation symbol, each of the remaining contiguous modulation symbols includes a progressively different cyclic shift of the repeated user or pilot data of the modulation symbol, and at least one of the initial modulation symbol and an adjacent modulation symbol of the plurality of contiguous modulation symbols includes at least a portion of a first cyclic prefix.

49. The base station of claim 48, configured to perform the method of any of claims 35-47.