Abstract: 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 ?g/3 to ?g/5, where ?g. is a center wavelength of the bandpass filter passband.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Methods and systems which provide for synchronization target selection by configuring a network device to reselect a synchronization signal transmission timeslot for synchronization target searching by the network device are described. Synchronization signal timeslot reselection may provide for downgrading a current stratum index to an artificial stratum index that does not accurately indicate a number of hops between the network device and a global synchronization source to allow for selection of available synchronization targets with stratum indices that are higher than or equal to the network device's stratum index without causing a synchronization loop. A synchronization signal pattern cycle structure having synchronization signal timeslots organized into multiple subcycles for accommodating synchronization signal timeslot reselection is utilized according to embodiments.

Abstract: Methods and systems which provide for synchronization target selection by configuring a network device to reselect a synchronization signal transmission timeslot for synchronization target searching by the network device are described. Synchronization signal timeslot reselection may provide for downgrading a current stratum index to an artificial stratum index that does not accurately indicate a number of hops between the network device and a global synchronization source to allow for selection of available synchronization targets with stratum indices that are higher than or equal to the network device's stratum index without causing a synchronization loop. A synchronization signal pattern cycle structure having synchronization signal timeslots organized into multiple subcycles for accommodating synchronization signal timeslot reselection is utilized according to embodiments.

Abstract: The present disclosure relates to methods and systems for selection of synchronization targets. Embodiments of the present disclosure provide for selecting a synchronization target for a network device, within operational network constraints, when the network device loses its current synchronization target. When a network device loses its current synchronization target, the stratum index of the network device is downgraded to an artificial stratum index before a selection of a new synchronization target is made. The artificial stratum index is broadcast to children network devices. Downgrading the stratum index to an artificial stratum index allows for selection of available synchronization target network devices with stratum indices higher than or equal to the network device's stratum index. After selection of a new synchronization target, the network device's stratum index is updated, and the new updated stratum index of the network device is broadcast to the children network devices of the network device.

Abstract: The present disclosure relates to methods and systems for selection of synchronization targets. Embodiments of the present disclosure provide for selecting a synchronization target for a network device, within operational network constraints, when the network device loses its current synchronization target. When a network device loses its current synchronization target, the stratum index of the network device is downgraded to an artificial stratum index before a selection of a new synchronization target is made. The artificial stratum index is broadcast to children network devices. Downgrading the stratum index to an artificial stratum index allows for selection of available synchronization target network devices with stratum indices higher than or equal to the network device's stratum index. After selection of a new synchronization target, the network device's stratum index is updated, and the new updated stratum index of the network device is broadcast to the children network devices of the network device.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 MINO 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.

Abstract: 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.

Abstract: The presently claimed invention provides a method of channel estimation in a multi-user massive Multiple-Input Multiple-Output system. Candidate pilots are selected for each user equipment based on their spatial correlation matrices. Through determining the similarity of spatial correlation matrices among different user equipments, shared pilots among them can be found, and a base station can transmit a union set of pilots for channel estimation. The present invention is able to provide high channel estimation accuracy and reduce training signal resource.