One of a plurality of radio communication apparatuses (100) becomes a master apparatus (100-M), and a rest of them become slave apparatuses (100-S). The master apparatus and each of the slave apparatus includes a plurality of transceivers (31) each composed of a transmitter and a receiver and first ports (55 and 56). The master apparatus further includes a calibration transceiver (51). The first port of the master apparatus is connected to the first port of the slave apparatus via an RF cable. When transmission calibration is performed, each transmitter of the slave apparatus transmits a transmission calibration signal to the calibration transceiver of the master apparatus via the RF cable. When reception calibration is performed, the calibration transceiver of the master apparatus transmits a reception calibration signal to each receiver of the slave apparatus via the RF cable.

One of a plurality of radio communication apparatuses (100) becomes a master apparatus (100-M), and a rest of them become slave apparatuses (100-S). The master apparatus and each of the slave apparatus includes a plurality of transceivers (31) each composed of a transmitter and a receiver and first ports (55 and 56). The master apparatus further includes a calibration transceiver (51). The first port of the master apparatus is connected to the first port of the slave apparatus via an RF cable. When transmission calibration is performed, each transmitter of the slave apparatus transmits a transmission calibration signal to the calibration transceiver of the master apparatus via the RF cable. When reception calibration is performed, the calibration transceiver of the master apparatus transmits a reception calibration signal to each receiver of the slave apparatus via the RF cable.

A UE is configured to perform Radio Link Monitoring (RLM) with a first Coverage Enhancement (CE) configuration that provides a first CE level. The first RLM configuration associated with the first CE configuration has a first radio-link-quality-improving threshold value that corresponds with a third distance from a base station that is closer to the base station than a second distance associated with an in-sync radio link quality threshold value associated with a first RLM configuration. The first RLM configuration also has a first radio-link-quality-improving-cancellation threshold value that corresponds with a fourth distance from the base station that is located farther from the base station than the third distance and closer to the base station than the first distance. If conditions are satisfied, the base station reconfigures the UE with a second RLM configuration and a second CE configuration having a second CE level lower than the first CE level.

A transmission apparatus (10) according to the present disclosure incudes: a correction value calculation unit (130) configured to calculate a correction value for correcting an initial standby time of a direct wave signal or an indirect wave signal based on a reception time of the direct wave signal and a reception time of the indirect wave signal that follows the direct wave signal, and a transmission time fluctuation compensation unit (140) configured to calculate the standby time by correcting the initial standby time using the correction value and cause the direct wave signal or the indirect wave signal to stand by in accordance with the standby time. The correction value calculation unit (130) calculates a correction value for increasing the standby time of the direct wave signal or reducing the standby time of the indirect wave signal.

A transmission apparatus (10) according to the present disclosure incudes: a correction value calculation unit (130) configured to calculate a correction value for correcting an initial standby time of a direct wave signal or an indirect wave signal based on a reception time of the direct wave signal and a reception time of the indirect wave signal that follows the direct wave signal, and a transmission time fluctuation compensation unit (140) configured to calculate the standby time by correcting the initial standby time using the correction value and cause the direct wave signal or the indirect wave signal to stand by in accordance with the standby time. The correction value calculation unit (130) calculates a correction value for increasing the standby time of the direct wave signal or reducing the standby time of the indirect wave signal.

A communication system includes a signal source for transmitting downlink signals and receiving uplink signals to and from an indoor signal coverage area; and a distributed antenna system interposed between the signal source and the indoor signal coverage area. The distributed antenna system includes an antenna monitoring unit connected to at least one service antenna through a distribution network. The at least one antenna transmits and receives the downlink signals and the uplink signals to and from at least one terminal unit within the indoor coverage area. The antenna monitoring unit includes an RFID transceiver that communicates with at least one RFID tag attached to the at least one antenna and detects the location of a point of anomaly with respect to that one antenna when a signal from the at least one RFID tag is not received by the RFID transceiver, or when a power level measured by the RFID tag and reported back to the RFID transceiver falls below a predetermined threshold level.

A communication system includes a signal source for transmitting downlink signals and receiving uplink signals to and from an indoor signal coverage area; and a distributed antenna system interposed between the signal source and the indoor signal coverage area. The distributed antenna system includes an antenna monitoring unit connected to at least one service antenna through a distribution network. The at least one antenna transmits and receives the downlink signals and the uplink signals to and from at least one terminal unit within the indoor coverage area. The antenna monitoring unit includes an RFID transceiver that communicates with at least one RFID tag attached to the at least one antenna and detects the location of a point of anomaly with respect to that one antenna when a signal from the at least one RFID tag is not received by the RFID transceiver, or when a power level measured by the RFID tag and reported back to the RFID transceiver falls below a predetermined threshold level.

Systems and associated methods for reciprocity calibration of multiple-input multiple-output (MIMO) wireless communication are disclosed herein. In one embodiment, a method for reciprocity calibration of the MIMO system includes transmitting a pilot symbol by a transmitter (TX) of the reference antenna and receiving the pilot symbol by receivers (RXes) of antennas of a base station as r.sub.i,0 pilot symbols. (Index “i” denotes individual antenna “i” of the base station, and “0” denotes the reference antenna.) The method further includes transmitting the received pilot symbols by TXes of the antennas of the base station, receiving the pilot symbols transmitted by the antennas of the base station by the reference antenna as r.sub.0,i pilot symbols, and calculating non-reciprocity compensation factors as

[00001]$\frac{r_{i,0}}{r_{0,i}}.$

The present disclosure discloses an adaptive MIMO detection method and system. The method includes the following steps: a) determining whether a Signal to Noise Ratio of a data packet is greater than a set threshold for Signal to Noise Ratio, and if yes, performing ZF preprocessing on the channel matrix, and if not, performing MMSE preprocessing on the channel matrix; b) performing sorted QR decomposition on the channel matrix processed in step a) to obtain a plurality of decomposition matrices; c) determining whether a condition number of the channel matrix of the data packet is greater than a set threshold for condition number of the channel, and if yes, Lattice Reduction is performed on the decomposition matrices obtained in step b); d) determining whether an estimated value of an interference term of the channel matrix is greater than a threshold for the estimated value of the interference term of the channel matrix, and if yes, SIC detection mode is selected for MIMO detection on the data packets, and if not, K-best detection mode is selected for MIMO detection on the data packets; and e) according to processing results from steps a) to d), performing MIMO detection on the data packet.

The invention provides a computing device for determining and conveying a bandwidth coverage of an optical communication modality within a space, wherein the space comprises at least one optical transmitter arranged for communicating over said optical communication modality; wherein the computing device comprises a controller configured to: obtain configuration data characterizing a configuration of said space; obtain lighting data characterizing the at least one optical transmitter; determine the bandwidth coverage of the optical communication modality within the space based on the configuration data and the lighting data; wherein the computing device comprises an output interface configured to: convey a signal indicative of the bandwidth coverage of the optical communication modality within the space.