Network-side receiver for receiving high-speed transmission signals

Abstract

Calculating the phase difference of the OFDM symbols of the PUCCH from the OFDM symbols of the first and second DM-RSs, the OFDM symbols of the second and third DM-RSs, and the OFDM symbols of the first and third DM-RSs; correlating the OFDM symbols across all DM-RSs; determining the Doppler shift reported to layer 2; compensating the channel estimation results and data symbols with the Doppler shift; performing a first-level phase correction for the PUSCH by correcting the phase on the output samples of the IDFT from the Doppler shift received from layer 2; measuring the phase deviation on the output of the first-level phase correction; accumulating the measured phase deviation and the received Doppler shift; reporting the accumulated phase correction to layer 2; and performing a second-level phase correction. A technique for receiving PUSCH and PUCCH transmitted by a high-speed transmitter is provided.

Description

Technical Field

[0001] In some embodiments, the subject matter here generally relates to mobile wireless communication systems, and more specifically, to a network-side receiver that receives wireless signals transmitted from a mobile-type device moving at high speed.

Background Art

[0002] The introduction and rapid expansion of digital wireless networks in the 1990s marked the beginning of the wireless revolution. Commercial wireless providers migrated from analog to digital wireless technologies that enable more efficient use of wireless resources, leading to an increase in wireless voice traffic and a dramatic increase in wireless digital data services. Subsequently, a paradigm shift from wired to wireless occurred. Wireless computer networks, wireless Internet, etc. are now expected to be accessible almost everywhere.

[0003] Wireless users may include conventional mobile phone users and portable computing devices such as laptop computers or tablets. The difference between modern mobile phones and personal computing devices has become difficult to distinguish. Modern mobile phones have become personal computing devices that host applications or services for applications such as word processing, spreadsheets, etc., which are typically found on personal or business computing devices, including calls, texts, messaging, e-mail, video recording and viewing, and live streaming.

[0004] Wireless access is available in substantially all metropolitan areas. In addition, it has become common sense for wireless users to access their devices wherever they go, unless there are special restrictions. For example, users expect wireless access to be available while they are moving by car, bus, ship, train, etc.

[0005] To establish and maintain a wireless connection between wireless devices, including a mobile device and a wireless network receiver such as a base station or eNB, the base station or eNB must be able to decode the Physical Uplink Shared Channel (PUSCH) and the Physical Uplink Control Channel (PUCCH).

[0006] Some land-based transportation modes provide movement at high speeds or rates (e.g., the Shinkansen can move at speeds exceeding 350 kph or 217 mph).

Summary of the Invention

Problems to be Solved by the Invention

[0007] Conventional wireless network receivers (e.g., eNB) may be unable to decode PUSCH and PUCCH due to the high phase deviation caused by the Doppler shift in the signals transmitted in a high-speed environment. Although WiFi services may be available in some modes of transportation, access is restricted and a mobile device with WiFi capabilities is required.

[0008] Thus, there is a need for a solution that enables a network receiver such as a base station or eNB to receive signals transmitted while the transmitting device is moving at a high speed or rate.

Means for Solving the Problems

[0009] In one general aspect, a method for decoding a Physical Uplink Shared Channel (PUSCH) and a Physical Uplink Control Channel (PUCCH) received by a receiver in a high-speed environment is provided. The method may include calculating a phase difference of OFDM symbols of the PUCCH for first, second, and third Demodulation Reference Signals (DM-RS) that are consecutive DM-RS symbols of the PUCCH received by the receiver, the OFDM symbol of the first DM-RS and the OFDMA symbol of the second DM-RS of the PUCCH, the OFDMA symbol of the second DM-RS and the OFDM symbol of the third DM-RS of the PUCCH, and the OFDM symbols of the first and third DM-RS of the PUCCH. The method may include correlating the OFDM symbols of the first and second DM-RS, the second and third DM-RS, and the first and third DM-RS. Further, the method may include determining a Doppler shift proportional to the phase difference across all DM-RS symbols in the channel. The method may include reporting the Doppler shift to layer 2 (L2) of the protocol stack. Additionally, the method may include compensating channel estimation results and data symbols with the Doppler shift. The method may include equalizing and demodulating the PUCCH. Further, the method may include performing a first level of phase correction for the PUSCH received by the receiver by correcting a phase on output samples of an Inverse Discrete Fourier Transform (IDFT) from the Doppler shift received from layer 2. The method may additionally include measuring a phase deviation on the output of the first level of phase correction and accumulating the measured phase deviation on the output of the first level of phase correction and the Doppler shift received from layer 2 to obtain an accumulated phase correction. The method may include reporting the accumulated phase correction to layer 2. Additionally, the method may include performing a second level of phase correction and demodulating the PUSCH according to the measured phase deviation of the output of the first level of phase correction.Other embodiments of this aspect include a corresponding computer system, apparatus, and computer program recorded on one or more computer storage devices each configured to perform an action of the method.

[0010] The implementation may include one or more of the following features. Measuring the phase deviation on the output of the first-level phase correction, and for symbols in the second, third, and fourth quadrants respectively, applying phase shifts of -π / 4, -π / 2, and -π / 3 radians to move all quadrature amplitude modulation (QAM) symbols to the first quadrant. The method may include calculating the difference between the average phase of the QAM symbols and the expected average phase of π / 4 radians or 45 degrees. Performing the first-level phase correction for the PUSCH includes receiving the Doppler shift reported by layer 1 to layer 2, and when the value of the Doppler shift received from layer 2 is zero, performing the second-level phase correction twice. The method in which the phase deviation is measured between all DM-RS symbols. The implementation of the described technology may include hardware, a method or process, or a computer tangible medium.

[0011] In other general aspects, an apparatus is provided for decoding a physical uplink shared channel (PUSCH) and a physical uplink control channel (PUCCH) received by a receiver in a high-speed environment.

[0012] For the orthogonal frequency division multiplexing (OFDM) symbols of the first DM-RS, the second DM-RS, and the third DM-RS, which are consecutive demodulation reference signals (DM-RS) symbols of the PUCCH received by the receiver, calculate the phase difference of the OFDM symbols of the PUCCH between the OFDM symbol of the first DM-RS and the OFDMA symbol of the second DM-RS of the PUCCH, between the OFDMA symbol of the second DM-RS and the OFDM symbol of the third DM-RS of the PUCCH, and between the OFDM symbols of the first DM-RS and the third DM-RS of the PUCCH; correlate the OFDM symbols of the first DM-RS and the second DM-RS, the second DM-RS and the third DM-RS, and the first DM-RS and the third DM-RS; determine a Doppler shift proportional to the phase difference across all DM-RS symbols in the channel; report the Doppler shift to layer 2 of the protocol stack; compensate the channel estimation result and data symbols with the Doppler shift; equalize and demodulate the PUCCH; perform a first-level phase correction for the PUSCH received by the receiver by correcting the phase on the output samples of the inverse discrete Fourier transform (IDFT) from the Doppler shift received from layer 2; measure the phase deviation on the output of the first-level phase correction; accumulate the measured phase deviation on the output of the first-level phase correction and the Doppler shift received from layer 2 to obtain the accumulated phase correction; report the accumulated phase correction to layer 2; perform a second-level phase correction according to the measured phase deviation of the output of the first-level phase correction; and demodulate the PUSCH. To perform the above, it may include a processor circuit configured to execute a plurality of instructions and coupled to a memory. Other embodiments of this aspect include a corresponding computer system and a computer program recorded on one or more computer storage devices, each configured to execute the actions of the device.

[0013] The implementation may include one or more of the following features. An apparatus that measures the phase deviation on the output of the first-level phase correction and includes moving all quadrature amplitude modulation (QAM) symbols to the first quadrant by applying phase shifts of -π / 4, -π / 2, and -π / 3 radians to the symbols in the second, third, and fourth quadrants, respectively. An apparatus further configured to execute a plurality of instructions for the processor circuit to calculate the difference between the average phase of the QAM symbols and an expected average phase of π / 4 radians or 45 degrees. An apparatus in which the second-level phase correction is executed twice if the value of the Doppler shift received from layer 2 is zero. An apparatus that performs the first-level phase correction for PUSCH and includes receiving the Doppler shift reported by layer 1 to layer 2. An apparatus in which the phase deviation is measured between all DM-RS symbols. The implementation of the described technique may include hardware, a method or process, or a computer tangible medium.

[0014] In yet another general aspect, a communication system is provided. The communication system includes a mobile device configured to transmit a physical uplink shared channel (PUSCH) and a physical uplink control channel (PUCCH) in a high-speed environment, and an eNodeB. The eNodeB calculates the phase difference of the OFDM symbols of the PUCCH from the OFDM symbols of the first DM-RS and the second DM-RS of the PUCCH, the OFDMA symbols of the second DM-RS and the third DM-RS of the PUCCH, and the OFDM symbols of the first DM-RS and the third DM-RS of the PUCCH, which are consecutive demodulation reference signal (DM-RS) symbols received by the receiver from the mobile device; correlates the OFDM symbols of the first DM-RS and the second DM-RS, the second DM-RS and the third DM-RS, and the first DM-RS and the third DM-RS; determines a Doppler shift proportional to the phase difference across all DM-RS symbols in the channel; reports the Doppler shift to layer 2 of the protocol stack; compensates the channel estimation result and data symbols with the Doppler shift; equalizes and demodulates the PUCCH; performs a first-level phase correction for the PUSCH received by the receiver by correcting the phase on the output samples of the inverse discrete Fourier transform (IDFT) from the Doppler shift received from layer 2; measures the phase deviation on the output of the first-level phase correction; accumulates the first-level phase correction with the measured phase deviation to obtain the accumulated phase correction; reports the accumulated phase correction to layer 2; performs a second-level phase correction according to the measured phase deviation of the output of the first-level phase correction; and demodulates the PUSCH. Other embodiments of this aspect include a corresponding computer system and a computer program recorded on one or more computer storage devices, each configured to perform the actions of the method.

[0015] The implementation may include one or more of the following features. A communication system that includes moving all quadrature amplitude modulation (QAM) symbols to the first quadrant by measuring the phase deviation on the output of the first-level phase correction and applying phase shifts of -π / 4, -π / 2, and -π / 3 radians to the symbols in the second, third, and fourth quadrants, respectively. A communication system further configured such that the eNodeB calculates the difference between the average phase of the QAM symbols and the expected average phase of π / 4 radians or 45 degrees. A communication system in which the second-level phase correction is performed twice if the Doppler shift received from layer 2 is zero. A communication system that includes receiving, by layer 1, a Doppler shift reported by layer 1 to layer 2 and performing a first-level phase correction on the PUSCH. A communication system in which the phase deviation is measured among all DM-RS symbols. The implementation of the described technology may include hardware, a method or process, or a computer-readable medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the following drawings:

[0017] FIG. 1 illustrates a communication link between a mobile device and a network device according to an embodiment,

[0018] FIG. 2 illustrates a generalized PUSCH reception chain,

[0019] FIG. 3 illustrates a generalized PUCCH reception chain,

[0020] FIG. 4 shows a QPSK constellation diagram,

[0021] FIG. 5 shows a 16 QAM constellation diagram,

[0022] FIG. 6 illustrates a PUCCH receiver processing chain according to some embodiments,

[0023] FIG. 7 illustrates a PUSCH receiver processing chain according to some embodiments,

[0024] FIG. 8 is a flowchart of an example of a process for receiving PUCCH transmitted from a high-speed mobile device,

[0025] FIG. 9 is a flowchart of an example of a process for receiving PUSCH transmitted from a high-speed mobile device. DETAILED DESCRIPTION OF THE INVENTION

[0026] FIG. 1 illustrates a communication link between a mobile device and a network device. The network device 102, which may be a base station (eNB), an access point, etc., transmits a signal 106 to the mobile device 104 and receives a signal 108 transmitted by the mobile device 104. The signal 106 may be represented as a downlink (DL) signal, and the signal 108 may be represented as an uplink (UL) signal. The mobile device 104 receives the signal 106 from the network device 102 and transmits the signal 108 to the network device 102.

[0027] There are significant differences between UL and DL signals in a wireless communication system such as LTE. These differences include transmission and multiplexing schemes that can result in different physical layer processing. For example, UL may be based on single carrier frequency division multiple access (SC-FDMA), and DL may be based on orthogonal frequency division multiple access (OFDMA). SC-FDMA modulation may have a lower peak-to-average power ratio, which can result in a lower-cost amplifier and less power consumption. User data may be modulated onto a single carrier modulation format and modulated using higher-order modulation such as quadrature phase shift keying (QPSK), 16-quadrature amplitude modulation (QAM), or 64 QAM. In 16 QAM, a carrier may be modulated to any of 16 different phase and amplitude states, and in 64 QAM, a carrier may be modulated to any of 64 different phase and amplitude states.

[0028] The uplink signal may not have a dedicated synchronization signal. The uplink frame can be synchronized using the Physical Uplink Control Channel Demodulation Reference Signal (DM-RS). The following description focuses on the Physical Uplink Shared Channel (PUSCH) and the Physical Uplink Control Channel (PUCCH). The PUSCH carries user data and control signal data. The control data information may be multiplexed with the user data before the discrete Fourier transform (DFT) spreading module in the uplink single-carrier frequency-division multiple access (SC-FDMA) physical layer.

[0029] Figure 2 illustrates a generalized PUSCH reception chain. The PUSCH signal 202 is received at 204. At 204, the signal is equalized and the inverse discrete Fourier transform (IDFT) is performed. At 206, the PUSCH signal 202 is demodulated.

[0030] Figure 3 illustrates a generalized PUCCH reception chain. The PUCCH signal 302 is received at 304. At 304, channel estimation is performed on the DM-RS symbols of the PUCCH. At 306, channel equalization is performed, and at 308, the PUCCH is demodulated. The PUSCH reception chain shown in the example of Figure 2 and the PUCCH reception chain shown in the example of Figure 3 are examples of reception chains that may not be able to decode the PUSCH and PUCCH transmitted by a transmitter moving at a high speed rate.

[0031] Figure 4 shows a QPSK constellation diagram. Depending on the modulation technique used for digital communication, the variations applied to the carrier are limited as discrete information is transmitted. The original signal is divided into a set of independent components I and Q. The data is divided into two channels (I and Q). Two bits are transmitted simultaneously (one bit per channel). Two carriers are transmitted in combination. Since the I and Q components are separated by 90°, they may be interpreted as orthogonal or in-phase quadrature. In polar representation, as illustrated at 402, the magnitude and phase are represented together. Note that the modulation of PUCCH is generally QPSK.

[0032] With QPSK modulation, the carrier can vary with respect to phase rather than frequency. The QPSK signal shifts between discrete phase states separated by 90°. For this reason, a QPSK symbol may be represented by four discrete values. As an example, the discrete values "00", "01", "10" and "11" are shown at 402. In the QPSK modulation shown at 402, "11" may represent a 45° discrete value, "01" may represent a 135° discrete value, "00" may represent a 225° discrete value, and "10" may represent a 315° discrete value. Here, each discrete value has a carrier amplitude of 1.0.

[0033] The QPSK constellation diagram at 404 illustrates equalized QPSK signals centered on their respective corresponding discrete values. This illustrates a QPSK constellation without significant Doppler shift.

[0034] An inclined QPSK constellation diagram is shown in 406. The inclined QPSK constellation diagram may be caused by Doppler shift (the inclination increases as the Doppler shift increases). The Doppler shift appears as a phase ramp across the OFDM symbol. This may also be viewed as a deviation in the angle of the complex symbol. The OFDM symbol immediately adjacent to the DM-RS may not show a large inclination, but the symbols far from the DM-RS may have a significant inclination that cannot be compensated. For this reason, signals transmitted from a device moving at a high speed rate may be difficult or impossible to decode by a conventional network receiver due to the high phase deviation caused by Doppler spread.

[0035] Figure 4 illustrates the QPSK constellation, and it is understood that the aforementioned Doppler shift may be the same in a QAM signal (e.g., a 16-QAM modulated signal). In QAM modulation, discrete values correspond to phase and amplitude states. The QAM constellation diagram may be the same as the QPSK constellation diagram having discrete values at 45, 135, 225, and 315 degrees.

[0036] Figure 5 shows a 16-QAM constellation diagram. In a 16-QAM modulated signal, a continuous bit stream may be represented as a sequence and divided into four groups in each of the four quadrants. In the 16-QAM constellation diagram 502, each quadrant may be interpreted as including 4 groups. In 16-QAM, six bits are used to represent the phase and amplitude states. That is, four I and four Q values are used to generate four bits per symbol (2 4 = 16). Thus, the amplitude and phase of the wireless signal may be regulated to one of 16 different discrete and measurable states as shown in 502.

[0037] It is understood that the inclined QAM constellation may be similar to the inclined QPSK diagram shown in 406, which is caused by Doppler shift (the inclination increases as the Doppler shift increases).

[0038] Note that PUCCH does not use DFT SC-FDMA precoding used in PUSCH data symbols. Also, as described above, the modulation of PUCCH is generally QPSK. The 4 QAM constellation is substantially the same as QPSK.

[0039] FIG. 6 illustrates a PUCCH receiver processing chain according to some embodiments. The highlighted portion represents new processing that may be implemented to solve the problem of receiving PUCCH signals transmitted by a transmitter moving at a high speed rate.

[0040] PUCCH channel estimation for DM-RS is performed at 602. DM-RS is a reference signal for PUCCH. PUCCH formats 1x and 2x have a plurality of OFDM symbols carrying pilot signals.

[0041] PUCCH format 1x typically has three DM-RS symbols located in the middle of the PUCCH slot. PUCCH format 2x typically has two DM-RS symbols. Here, the DM-RS symbols are typically located in the second and second-to-last symbols of the PUCCH slot. Thus, there are differences between the processing of PUCCH format 1x and PUCCH format 2x. The following is a description directed to PUCCH format 1x.

[0042] For PUCCH format 1x, the phase differences of the OFDM symbols between the first DM-RS and the second DM-RS, the second DM-RS and the third DM-RS, and the first DM-RS and the third DM-RS are calculated. That is, the phase differences between all DMRS symbols are calculated. The OFDM symbols of the first DM-RS and the second DM-RS, the second DM-RS and the third DM-RS, and the first DM-RS and the third DM-RS are correlated, and the Doppler shift is determined. The Doppler shift is proportional to the phase differences across all DM-RS symbols in the channel. The Doppler shift is reported as a phase deviation to L2 at 606.

[0043] At 608, phase correction for the DM-RS and data symbols of the PUCCH is performed. That is, at 608, the phases of the DM-RS and data symbols are compensated by the estimated phase deviation performed at 604. At 610, equalization of the PUCCH is performed on the output of 608.

[0044] PUCCH channel estimation is performed using DM-RS symbols at 602. For a PUCCH transmitted by a transmitter moving at a high speed rate, a phase deviation that results in a high Doppler shift is estimated at 604. The phase deviation estimated at 604 is reported to L2 at 606.

[0045] FIG. 7 illustrates a PUSCH receiver processing chain according to some embodiments. The highlighted portion represents new processing that may be implemented to solve the problem of receiving a PUSCH signal transmitted by a transmitter moving at a high speed rate.

[0046] The received PUSCH is equalized, and the Inverse Discrete Fourier Transform (IDFT) is performed at 702. At 704, Doppler shift information is received from layer 2. The Doppler shift is proportional to the phase deviation. At 706, a first-level phase correction is performed. The first-level phase correction is performed on the output samples of the IDFT using the Doppler shift information received from L2. That is, the phase of the IDFT output samples may be corrected according to the Doppler shift information received from L2 at 704. Here, the Doppler shift appears as phase spread across the OFDM symbol.

[0047] The phase deviation on the output of the first-level phase correction 706 is measured at 708. The phase deviation may be measured by moving all QAM symbols to the first quadrant by applying phase shifts of -π / 4, -π / 2, and -π / 3 radians to the symbols in the second, third, and fourth quadrants, respectively. Measuring the phase deviation may include calculating the difference between the expected average phase of π / 4 radians or 45 degrees.

[0048] To obtain the cumulative phase correction, the phase deviation on the output of the measured first-level phase correction at 706 and the Doppler shift received from layer 2 at 704 are accumulated at 710. The cumulative phase correction is reported to L2 at 712. This may be regarded as a type of feedback in which the phase deviation measured at 708 is refined or improved. As a generalized example, assume that a Doppler shift corresponding to a value of 45° (or the equivalent value in radians) is taken at 704, and a phase correction of another 5° is determined as the measurement result of the phase deviation at 708. At 710, 45° is accumulated with 5°, and 50° is reported to L2. The process at 706 - 710 may be repeated so that the phase deviation reported at 712 is refined in each iteration.

[0049] At 714, second-level phase correction is performed on the output of 710. At 714, the phase is corrected based on the output of the first-level phase correction at 706 and the phase corrections measured and accumulated at 708 - 710. At 716, the PUSCH is demodulated.

[0050] The Doppler shift information received from L2 at 704 may correspond to the phase deviation estimated and reported from the PUCCH (see 604 and 608 in FIG. 6). There may be cases where the PUCCH has not been received yet, or the reported phase deviation of the PUCCH is old or not the latest and not valid. In such cases, the Doppler shift information received from L2 at 704 may be reported as a value of zero (0).

[0051] If the Doppler shift received from L2 is zero, the processing at 714 may be executed twice.

[0052] The PUCCH processes at 604, 606, and 608 and the PUSCH processes at 704 and 706 - 714 provide solutions to the problem that a conventional network receiver cannot decode PUCCH and / or PUSCH transmitted by a transmitter moving at a high speed rate. These processes determine the phase deviation caused by the high Doppler spread of the high-speed transmitter and compensate for the phase deviation before demodulating the PUCCH and / or PUSCH.

[0053] FIG. 8 is a flowchart of an example of a process for receiving what is transmitted from a high-speed mobile device.

[0054] As shown in FIG. 8, process 800 may include calculating a phase difference of the PUCCH OFDM symbol from the OFDM symbols of the first DM-RS and the second DM-RS, the second DM-RS and the third DM-RS, and the first DM-RS and the third DM-RS of the PUCCH received by the network receiver at 802. For example, the receiver may calculate the phase difference of the ODMA symbol of the PUCCH from the OFDM symbols of the first DM-RS and the second DM-RS, the second DM-RS and the third DM-RS, and the first DM-RS and the third DM-RS of the PUCCH as described above.

[0055] Process 800 may include, at 804, correlating OFDM symbols of the first DM-RS and the second DM-RS, the second DM-RS and the third DM-RS, and the first DM-RS and the third DM-RS. For example, a receiver or device may correlate OFDM symbols of the first DM-RS and the second DM-RS, the second DM-RS and the third DM-RS, and the first DM-RS and the third DM-RS as described above. Process 800 may include, at 806, determining a Doppler shift proportional to a phase difference across DM-RS symbols in a channel. For example, a receiver or device may determine a Doppler shift proportional to a phase difference across DM-RS symbols in a channel as described above. Process 800 may include, at 808, reporting the Doppler shift to layer 2 (L2) of a protocol stack. For example, a receiver or device may report the Doppler shift to L2 of a protocol stack as described above. As further shown in FIG. 8, process 800 may include, at 810, compensating channel estimation results and data symbols with the Doppler shift. For example, a receiver or device may compensate channel estimation results and data symbols with the Doppler shift as described above. Also, as shown in FIG. 8, process 800 may include, at 812, equalizing and demodulating a PUCCH. For example, a receiver or device may equalize and demodulate a PUCCH as described above.

[0056] FIG. 8 shows an example of blocks of process 800, but in some implementations, process 800 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those shown in FIG. 8. Additionally or alternatively, two or more of the blocks of process 800 may be executed in parallel.

[0057] Process 800 may include additional implementations, such as any single implementation or any combination of the implementations described below, and / or combinations with one or more other processes described elsewhere.

[0058] FIG. 9 is a flowchart of an example of a process for receiving a PUSCH transmitted from a high-speed mobile device.

[0059] Process 900 may include, at 902, performing a first-level phase correction on the received PUSCH by correcting the phase on the output samples of the IDFT from the Doppler shift received from L2. For example, a receiver of a device may perform a first-level phase correction on the PUSCH received by the receiver by correcting the phase on the output samples of the IDFT from the Doppler shift received from L2 as described above. Also, as shown in FIG. 9, process 900 may include, at 904, measuring a phase deviation on the output of the first-level phase correction. For example, a receiver of a device may measure a phase deviation on the output of the first-level phase correction as described above. As further shown in FIG. 9, process 900 may include, at 906, accumulating the measured phase deviation on the output of the first-level phase correction and the Doppler shift received from L2 to obtain an accumulated phase correction. Process 900 may include, at 908, reporting the accumulated phase correction to L2. For example, a receiver of a device may report the accumulated phase correction to L2 as described above.

[0060] Also, as shown in FIG. 9, process 900 may include, at 910, performing a second-level phase correction according to the measured phase deviation of the output of the first-level phase correction. For example, a receiver or device may perform a second-level phase correction according to the measured phase deviation of the output of the first-level phase correction, as described above. Process 900 may include, at 912, demodulating the PUSCH. For example, a receiver or device may demodulate the PUSCH, as described above.

[0061] FIG. 9 shows an example of blocks of process 900, but in some implementations, process 900 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks, compared to what is shown in FIG. 9. Additionally or alternatively, two or more of the blocks of process 900 may be executed in parallel.

[0062] Process 900 may include additional implementations, such as any single implementation or any combination of the implementations described below, and / or combinations with one or more other processes described elsewhere.

[0063] In a first implementation, measuring the phase deviation on the output of the first-level phase correction includes moving all quadrature amplitude modulation (QAM) symbols to the first quadrant by applying phase shifts of -π / 4, -π / 2, and -π / 3 radians to the symbols in the second, third, and fourth quadrants, respectively.

[0064] A second implementation may include, alone or in combination with the first implementation, process 900 calculating the difference between the average phase of the QAM symbols and the expected average phase of π / 4 radians or 45 degrees.

[0065] In a third implementation, performing the first-level phase correction for the PUSCH, alone or in combination with the first and second implementations, includes receiving a Doppler shift reported by layer 1 to layer 2.

[0066] In a fourth implementation, when the value of the Doppler shift received from layer 2 is zero, either alone or in combination with the first, second, and third implementations, the second-level phase correction is performed twice.

[0067] In a fifth implementation, either alone or in combination with one or more of the first through fourth implementations, the first, second, and third DM-RSs are consecutive DM-RS symbols.

[0068] In a sixth implementation, either alone or in combination with one or more of the first through fifth implementations, the phase deviation is measured between all DM-RS symbols.

[0069] Other variations to the disclosed embodiments can also be understood and enabled by those skilled in the art when implementing the features exemplified from the teachings of the drawings, the disclosure, and the appended claims.

[0070] In the claims, the term "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality.

[0071] A single processor, device, or other unit may perform the functions of several items recited in the claims. The mere fact that certain means are recited in mutually different dependent claims does not imply that a combination of these means cannot be used to advantage.

[0072] Operations such as obtaining, accessing, analyzing, capturing, comparing, determining, inputting, obtaining, outputting, providing, storing or being stored, calculating, simulating, receiving, warning, and stopping can be implemented as program code means of a computer program and / or as dedicated hardware.

[0073] The computer program may be stored and / or distributed on a suitable medium, such as an optical storage medium or a solid state medium, which is supplied together with other hardware or as part of other hardware, and / or may be distributed in other forms via the Internet or other wired or wireless communication systems, etc.

Claims

1. A method for decoding a Physical Uplink Shared Channel (PUSCH) and a Physical Uplink Control Channel (PUCCH) received by a receiver in a high-speed environment, comprising: For Orthogonal Frequency Division Multiplexing (OFDM) symbols of a first DM-RS, a second DM-RS, and a third DM-RS, which are consecutive Demodulation Reference Signals (DM-RS) symbols of the PUCCH received by the receiver, The OFDM symbol of the first DM-RS of the PUCCH and the OFDMA symbol of the second DM-RS, The OFDMA symbol of the second DM-RS of the PUCCH and the OFDM symbol of the third DM-RS, The OFDM symbols of the first DM-RS and the third DM-RS of the PUCCH, Calculating a phase difference of OFDM symbols of the PUCCH therefrom; Correlating the OFDM symbols of the first DM-RS and the second DM-RS, the second DM-RS and the third DM-RS, and the first DM-RS and the third DM-RS; Determining a Doppler shift proportional to the phase difference across all the DM-RS symbols in the channel; Reporting the Doppler shift to layer 2 of the protocol stack; Compensating a channel estimation result and data symbols with the Doppler shift; Equalizing and demodulating the PUCCH; Performing a first-level phase correction on the PUSCH received by the receiver by correcting a phase on output samples of an Inverse Discrete Fourier Transform (IDFT) from the Doppler shift received from layer 2; Measuring a phase deviation on the output of the first-level phase correction; Accumulating the measured phase deviation on the output of the first-level phase correction and the Doppler shift received from layer 2 to obtain an accumulated phase correction; Reporting the accumulated phase correction to layer 2; Performing a second-level phase correction according to the measured phase deviation of the output of the first-level phase correction; Demodulating the PUSCH; A method comprising the above steps.

2. Measuring the phase deviation on the output of the phase correction of the first level includes moving all quadrature amplitude modulation (QAM) symbols to the first quadrant by applying phase shifts of -π / 4, -π / 2, and -π / 3 radians to the symbols in the second, third, and fourth quadrants respectively, according to the method of claim 1.

3. The method of claim 2 further comprising calculating a difference between an average phase of the QAM symbol and an expected average phase of π / 4 radians or 45 degrees.

4. Performing the phase correction of the first level for the PUSCH includes receiving the Doppler shift reported by layer 1 to layer 2, according to the method of claim 1.

5. The method of claim 4 further comprising performing the phase correction of the second level twice if the value of the Doppler shift received from layer 2 is zero.

6. The phase deviation is measured among all the DM-RS symbols, according to the method of claim 1.

7. An apparatus for decoding a physical uplink shared channel (PUSCH) and a physical uplink control channel (PUCCH) received by a receiver in a high-speed environment, a memory configured to store a plurality of instructions, for orthogonal frequency division multiplexing (OFDM) symbols of a first DM-RS, a second DM-RS, and a third DM-RS, which are consecutive demodulation reference signals (DM-RS) symbols of the PUCCH received by the receiver, the OFDM symbol of the first DM-RS of the PUCCH and the OFDMA symbol of the second DM-RS, the OFDMA symbol of the second DM-RS of the PUCCH and the OFDM symbol of the third DM-RS, the OFDM symbol of the first DM-RS and the third DM-RS of the PUCCH, calculating a phase difference of the OFDM symbols of the PUCCH therefrom, correlating the OFDM symbols of the first DM-RS and the second DM-RS, the second DM-RS and the third DM-RS, and the first DM-RS and the third DM-RS, determining a Doppler shift proportional to the phase difference across all the DM-RS symbols in the channel, reporting the Doppler shift to layer 2 of the protocol stack. Compensating the channel estimation result and the data symbol with the Doppler shift, Equalizing and demodulating the PUCCH, Performing a first-level phase correction on the PUSCH received by the receiver by correcting the phase on the output samples of the inverse discrete Fourier transform (IDFT) from the Doppler shift received from layer 2, Measuring the phase deviation on the output of the first-level phase correction, Accumulating the measured phase deviation on the output of the first-level phase correction and the Doppler shift received from layer 2 to obtain an accumulated phase correction, Reporting the accumulated phase correction to layer 2, Performing a second-level phase correction according to the measured phase deviation of the output of the first-level phase correction, Demodulating the PUSCH, A processor circuit configured to execute the plurality of instructions and coupled to the memory for performing the above, An apparatus comprising.

8. The apparatus according to claim 7, wherein measuring the phase deviation on the output of the first-level phase correction includes moving all quadrature amplitude modulation (QAM) symbols to the first quadrant by applying phase shifts of -π / 4, -π / 2, and -π / 3 radians to the symbols in the second, third, and fourth quadrants, respectively.

9. The apparatus according to claim 8, wherein the processor circuit is further configured to execute the plurality of instructions to calculate the difference between the average phase of the QAM symbols and the expected average phase of π / 4 radians or 45 degrees.

10. The apparatus according to claim 7, wherein performing the first-level phase correction on the PUSCH includes receiving the Doppler shift reported by layer 1 to layer 2.

11. The apparatus according to claim 9, wherein when the value of the Doppler shift received from layer 2 is zero, the second-level phase correction is performed twice.

12. The apparatus according to claim 7, wherein the phase deviation is measured among all the DM-RS symbols.

13. A mobile device configured to transmit a physical uplink shared channel (PUSCH) and a physical uplink control channel (PUCCH) in a high-speed environment, Regarding the orthogonal frequency division multiplexing (OFDM) symbols of the first DM-RS, the second DM-RS, and the third DM-RS, which are consecutive demodulation reference signal (DM-RS) symbols received by a receiver from the mobile device, the OFDM symbol of the first DM-RS of the PUCCH and the OFDMA symbol of the second DM-RS, the OFDMA symbol of the second DM-RS of the PUCCH and the OFDM symbol of the third DM-RS, the OFDM symbols of the first DM-RS and the third DM-RS of the PUCCH, calculate the phase difference of the OFDM symbols of the PUCCH from, correlate the OFDM symbols of the first DM-RS and the second DM-RS, the second DM-RS and the third DM-RS, and the first DM-RS and the third DM-RS, determine a Doppler shift proportional to the phase difference across all the DM-RS symbols in the channel, report the Doppler shift to layer 2 of the protocol stack, compensate the channel estimation result and data symbols with the Doppler shift, equalize and demodulate the PUCCH, perform a first-level phase correction for the PUSCH received by the receiver by correcting the phase on the output samples of the inverse discrete Fourier transform (IDFT) from the Doppler shift received from layer 2, measure the phase deviation on the output of the first-level phase correction, accumulate the measured phase deviation on the output of the first-level phase correction and the Doppler shift received from layer 2 to obtain an accumulated phase correction, report the accumulated phase correction to layer 2, perform a second-level phase correction according to the measured phase deviation of the output of the first-level phase correction, demodulate the PUSCH, an eNodeB configured to execute, a communication system comprising.

14. Measuring the phase deviation on the output of the phase correction of the first level involves moving all quadrature amplitude modulation (QAM) symbols to the first quadrant by applying phase shifts of -π / 4, -π / 2, and -π / 3 radians to the symbols in the second, third, and fourth quadrants respectively, for the communication system according to claim 13.

15. The eNB is further configured to calculate the difference between the average phase of the QAM symbols and the expected average phase of π / 4 radians or 45 degrees, for the communication system according to claim 14.

16. Performing the phase correction of the first level for the PUSCH involves receiving the Doppler shift reported by layer 1 to layer 2, for the communication system according to claim 13.

17. If the Doppler shift received from layer 2 is zero, the phase correction of the second level is performed twice, for the communication system according to claim 15.

18. The phase deviation is measured among all the DM-RS symbols, for the communication system according to claim 13.

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