Hong Kong Applied Science and Technology Research Institute Company, Limited

Hong Kong Applied Science and Technology Research

Yuxian Zhang

Man Wai Kwan

Eric Kong Chau Tsang

Kong Chau Tsang

Xiangyu Liu

Man Wai Victor Kwan

Honglei Zhang

Ho Yin Chan

Zhonghui Zhang

Jia Ni

Yin Yang

Jiewei Ding

Yaming Luo

Wing Chau Chan

Jun Xu

Kanghao Jia

Victor Kwan

Eric Tsang

Xiaolong Huang

Yijing Chu

Yujiang Wu

Chang Li

Yibing Yao

Nan Li

Jianping Zheng

Mai Wai Kwan

Hong Hu

Yueping Wu

A method of estimating local oscillator leakage (LOL) for a radio frequency (RF) signal transmitter. The method comprises generating a transmitter wideband baseband signal (s(t)) with a direct current (DC) voltage element of the transmitter wideband baseband signal (s(t)) removed or blocked and an average of the transmitter wideband baseband signal (s(t)) set to zero. The method includes processing said transmitter wideband baseband signal (s(t)) to form a RF signal; processing the RF signal to obtain a receiver baseband signal (y(t)); and determining a magnitude of an average of the receiver baseband signal (y(t)) as comprising a magnitude of the transmitter DC offset.

Method of estimating local oscillator leakage

Described is a method of performing carrier frequency offset (CFO) estimation of physical channels in a mobile communications system. The method comprises the step of performing channel estimation of a received signal on a physical channel based on multiple orthogonal frequency division multiplex (OFDM) symbols in one or more reference signals (RSs). The method includes determining multiple phase rotation values Φ and corresponding time differences s between different OFDM symbols in the one or more RSs over a base phase rotation range comprising +/−π to obtain a first CFO estimation candidate ƒ. The base phase rotation range is extended to provide an extended phase rotation range of greater than +/−π to obtain additional CFO estimation candidates ƒ, ƒ. . . ƒwithin the extended phase rotation range.

Method of large frequency offset estimation for an OFDM communications system using reference signals

Described is a bandpass filter comprising a multi-layered body, a first resonator conductor formed on a first layer of the body and a second resonator conductor formed on a second, tower layer of the body. The first resonator conductor and the second resonator conductor comprise a first coupling area formed by only a partial overlap of the first resonator conductor and the second resonator conductor. A length of each said resonator conductor is in the range of &#x3bb;/3 to &#x3bb;/5, where &#x3bb;. is a center wavelength of the bandpass filter passband.

Multi-layer bandpass filter

Described is a method and apparatus for processing an uplink (UL) signal at a Physical Uplink Control Channel (PUCCH) in a wireless communication system to determine a discontinuous transmission (DTX) state. The method comprises receiving a UL channel signal at a PUCCH receiver apparatus and, after resource element (RE) demapping of said received UL channel signal in said PUCCH receiver apparatus, normalizing a signal power of at least one signal element or resource. The normalized power is compared to a selected, calculated or predetermined threshold and, based on said comparison, a determination is made on whether or not a DTX state has occurred.

Method and an apparatus for physical uplink control channel (PUCCH) discontinuous transmission (DTX) determination in a wireless communication system

Provided is a method for determining a Hybrid Automatic Repeat Request (HARQ) transmission signal. The method comprises receiving soft bits from a wireless communication physical channel uplink signal, said received soft bits being deemed to comprise HARQ LLRs and soft decoding said HARQ LLRs to output a hard ACK/NACK decision. The method includes processing said HARQ LLRs based on said hard ACK/NACK decision such that the processed HARQ LLRs map to a same or identical constellation point or points if the physical channel uplink signal contains an ACK or NACK transmission signal. The method also includes using said processed HARQ LLRs to determine if the physical channel uplink signal contains an ACK or NACK transmission signal or to determine if the physical channel uplink signal comprises discontinuous transmission (DTX).

Method and an apparatus for improving a determination of HARQ-ACK messages in a wireless communications system

Provided is a method and an apparatus for signaling allocation of resources in a joint transmission communication system. The method includes determining one of a plurality of resource allocation schemes to be implemented by two or more of a plurality of transmission points (TPs) comprising a set of coordinated TPs for enabling said two or more of said TPs to transmit data to a scheduled user equipment (UE). The method may comprise determining a bit length of a resource allocation field for a resource allocation signal message based on a number N of resource blocks groups (RBGs) related to a bandwidth of the joint transmission communication system and a number M of TPs comprising said set of coordinated TPs and further include formatting the resource allocation signal message to provide the resource allocation field based on said determined bit length. The resource allocation signal message is transmitted from only one of said set of coordinated TPs to said scheduled UE.

Method and apparatus for resource allocation signaling in a joint transmission cellular communication system

Systems and methods which provide for detection of a signal using resource elements in the frequency domain where the signal for which detection is provided is multiplexed with other signals having subcarrier spacing that is different than the signal for which detection is provided are disclosed. Embodiments may provide for detection of a physical random access channel (PRACH) signal in a cellular radio communication system using resource elements in the frequency domain, wherein the PRACH signal is multiplexed with signals of other channels (e.g., data and/or control channel signals) of the cellular radio communication system. A frequency domain filter, such as implementing inverse discrete Fourier transform (IDFT) with down-sampling using indices for PRACH recovery, may be utilized to extract PRACH samples from frequency domain resource elements provided in a resource grid corresponding to a different subcarrier spacing than that of the PRACH.

Frequency domain PRACH filter for PRACH signal recovery

Provided is a method of determining timing of arrival of a signal on a path to a receiver in a mobile wireless communications system. The method comprises obtaining a channel impulse response (CIR) of a signal received at the receiver and deriving a power characteristic of the CIR. The method includes producing a first derivative of the power characteristic with respect to time, selecting some or all extrema from the first derivative of the power characteristic as indicative of candidate signal paths, and selecting one or more of said candidate signal paths. The method preferably includes determining timing of arrival of a signal on a first path of arrival at the receiver by assessing an energy value of each of said candidate signal paths against a threshold value.

Method and apparatus for fine timing offset estimation

Provided is a method of determining Channel State Information (CSI) in a multiple input/multiple output (MIMO) wireless communication system. The CSI may comprise a Precoding Matrix Indicator (PMI) and/or a Rank Indicator (RI). The method comprises, for a matrix of channels comprising a link between a gNodeB (gNB) and a user equipment (UE), determining correlation values between all Discrete Fourier Transform (DFT) vectors and the observations from the channel matrix. The DFT vectors may include the horizontal vector direction and the vertical vector direction. The method includes selecting those DFT vectors in one or more selected vector directions having a correlation value greater than a predefined threshold to thereby identify a subset of all DFT vectors and determining said CSI from the selected subset of DFT vectors.

Method and apparatus for determining channel state information (CSI) in a multiple input/multiple output (MIMO) wireless communication system

The present disclosure relates to methods, devices, and systems for cell identification. For example, the systems, devices, and methods described herein may be used to detecting a secondary synchronization signal (SSS) index. In an aspect of the present disclosure, a method includes detecting, at an electronic device, a first SSS index based on a comparison between a first power value and a first threshold. The first power value is associated with a correlation power result between a received signal from a base station and a local SSS. The method also include determining, at the electronic device, a second threshold based on the first power value, and performing a comparison between a second power value and the second threshold. The second power value is determined based on the received signal.

Cell search in a wireless network

Provided is a method of base station (BS) for channel state information (CSI) acquisition in a massive multiple input/multiple output (MIMO) communication system. The method comprises the steps at the BS of sending a set of beamformed reference signals (RSs) to a user equipment (UE) and receiving from said UE an indication of a subset of said set of beamformed RSs and CSI acquired by said UE for only said subset of said set of beamformed RSs. Also provided is a further method and a user equipment (UE) for CSI acquisition. The further method comprises the steps at the UE of receiving from the BS the set of beamformed RSs; estimating a channel of each RS comprising said set of beamformed RSs; selecting a subset of said set of beamformed RSs; acquiring CSI for only said selected subset of said set of beamformed RSs; and communicating to said BS an indication of said selected subset of said set of beamformed RSs and reporting the CSI acquired for said selected subset of said set of beamformed RSs.

Method and apparatus for channel state information (CSI) reporting in a massive MIMO communications system

The presently claimed invention relates generally to a method and an apparatus for pilot decontamination for massive MIMO system and, more particularly, to a massive MIMO communication system based on channel estimation with topological interference alignment.

Method and apparatus of topological pilot decontamination for massive MIMO systems

A method for transmitting payload data from a base station (BS) to a user equipment (UE) via a MIMO channel is provided. Channel estimation is performed first and the channel-estimation result is used for optimizing data transmission. Instead of reporting CQI, RI and PMI to the BS, the UE reports a first channel transfer function characterizing an end-to-end process of obtaining received CSI-RS symbols from originally-sent CSI-RS symbols. Computation burden at the UE is reduced as computation of the CQI, RI and PMI is eliminated. At the BS, an effect caused by the antenna port-to-transceiver unit (AP-to-TXRU) virtualization operation is removed from the first channel transfer function to yield a second channel transfer function. With the second channel transfer function closer to the MIMO channel transfer function than the first one, the 'content' of the MIMO channel is better utilized in optimizing data-transmission performance.

Closed-loop massive MIMO system architecture

A method for timing synchronization of an OFDM signal is useful for a sniffing base station (BS) to establish BS synchronization with another BS in a mobile communication system. The method comprises estimating a timing offset of the signal from a reference sampling instant. In estimating the timing offset, first determine a maximum detection range of an estimable timing offset estimated solely by an observed phase difference between two pre-selected pilot symbols in the signal. Then the timing offset is determined as an integer multiple of the maximum detection range plus a residual timing offset. The multiplying integer is determined from a set of candidate integers. According to a candidate integer under consideration, a portion of an OFDM-signal sample sequence is masked out and a resultant signal to interference plus noise ratio (SINR) is computed. The multiplying integer is determined by identifying the candidate integer having the greatest SINR.

Timing offset estimation in an OFDM-based system by SINR measurement

This invention is concerned with estimating a massive multi-input multi-output (MIMO) channel. In one embodiment, the transmit antennas are first partitioned into antenna groups each comprising a subset of the transmit antennas such that a pre-determined level of channel-estimation accuracy is attainable. For each antenna group, training signals for estimating a group of channels associated with the antenna group are determined. In particular, the number of the antenna groups, the subset of the transmit antennas for forming the antenna group, and the training signals for the antenna group are determined based on spatial correlations of the massive MIMO channel, a maximum allowable total number of training signals and a transmit signal-to-noise ratio such that the pre-determined level of channel-estimation accuracy is achievable. Advantageously, the number of antenna groups is determined by identifying a highest number of antenna groups under a constraint that the pre-determined level is achievable.

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Hong Kong, China

Yuxian Zhang