# US 11,121,816 B2 · Symbol detection of massive MIMO systems with unknown symbol-dependent transmit-side impairments > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,121,816 B2 - Document ID: US11121816B2 - Status: Granted - Kind: B2 - Application number: 16/703,710 - Filed: 2019-12-04 - Published: 2021-06-10 - Granted: 2021-09-14 - Earliest claimed: 2019-12-04 - Assignees: Mitsubishi Electric Research Laboratories, Inc. - Applicants: Mitsubishi Electric Research Laboratories, Inc. - Inventors: Pu Wang; Toshiaki Koike-Akino; Milutin Pajovic; Philip Orlik - Web page: https://patentgrep.com/patent/US11121816B2 ## CPC - H04B 1/123: {using adaptive balancing or compensation means (adaptive filter circuits and algorithms H03H)} - H04L 1/0675: {characterised by the signaling} - H04B 7/0452: Multi-user MIMO systems - H04B 17/336: Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] - H04L 27/364: {Arrangements for overcoming imperfections in the modulator, e.g. quadrature error or unbalanced I and Q levels} - Y02D 30/70: in wireless communication networks - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract An apparatus for processing a perturbation quantity received in a wireless network. The perturbation quantity including a non-linear effect from at least one transmitted signal of the wireless network. The apparatus including a Base Station (BS) configured to establish a link between the BS and a user equipment (UE). A processing circuit is configured to implement receiver-side decoders. Wherein a receiver-side decoder is configurable to provide a recovery of unknown symbols perturbed by the perturbation quantity, the recovery is at a receiver-side and the perturbation is at the transmitter-side. Provide receiver-side decoding for symbol detection of symbol-dependent transmit-side perturbations by imposing a hierarchical signal model on the transmitted symbol. Wherein the decoding that is provided by the receiver-side decoders is used to recover the unknown symbols perturbed by the perturbation quantity and to identify symbol dependent perturbations, to reduce decoding processing costs by either the UE or the BS. ## Claims ### Claim 1 An apparatus for processing a perturbation quantity received in a wireless network, the perturbation quantity including a non-linear effect from at least one transmitted signal of the wireless network, the apparatus comprising: at least one Base Station (BS) having at least one antenna configured for data transmission, wherein the BS is configured for wireless communication with a User Equipment (UE) in the wireless network, and the BS is configured to establish a link between the BS and the UE, to provide a plurality of transmitted and uplink data streams; a processing circuit, configured to implement receiver-side decoders, wherein at least one receiver-side decoder of the receiver-side decoders is configurable to provide a remotely configurable recovery of unknown symbols perturbed by the perturbation quantity, wherein the recovery is at a receiver-side and the perturbation is at the transmitter-side, such that the receiver is either for an uplink transmission at the BS or for a downlink transmission at the UE; and provide receiver-side decoding for symbol detection of symbol-dependent transmit-side perturbations by imposing a hierarchical signal model on the transmitted symbol, and wherein the decoding that is provided by the receiver-side decoders is used to recover the unknown symbols perturbed by the perturbation quantity and to identify symbol dependent perturbations, to reduce an amount of decoding processing costs by either the UE or the BS. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the perturbation quantity includes one or a combination of non-linear impairments generated by non-linear characteristics of active devices, non-linear impairments generated by passive devices, non-linear impairments generated by harmonics in active devices or non-linear impairments generated by harmonics in passive devices. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the non-linear impairments generated by the non-linear characteristics of the active devices include one or a combination of non-linearities of power amplifiers, in-phase and quadrature (I/Q) imbalance, phase-drifts due to non-ideal oscillators, or carrier frequency offsets. ### Claim 4 (depends on 2) The apparatus of claim 2, wherein the non-linear impairments generated by the non-linear characteristics of the active devices include active devices that must be biased with an external power source which is not an input signal, and that the active devices are turned-on. ### Claim 5 (depends on 2) The apparatus of claim 2, wherein the non-linear impairments generated by passive devices include one or a combination of cables or antennas of the wireless network subjected to two or more high power tones. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the BS is a Base Transceiver Station (BTS) and the at least one antenna is an MIMO antenna array configured for beamforming and MIMO transmission. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the hierarchical signal model on the transmitted symbol is a low-complexity symbol detection algorithm, that incorporates a hierarchical truncated Gaussian mixture prior model. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the hierarchical truncated Gaussian mixture prior model is further imposed on the perturbed transmitted symbol to enforce a finite alphabet nature. ### Claim 9 (depends on 7) The apparatus of claim 7, wherein the low-complexity symbol detection algorithm uses principles of variational Bayesian inference to develop a factorized or decoupled iterative detection algorithm. ### Claim 10 (depends on 1) The apparatus of claim 1, further including a control element in communication with the processing circuit to implement an action, based on the recovery of the unknown symbols perturbed by the perturbation quantity. ### Claim 11 A system for processing a perturbation quantity received in a wireless network, the perturbation quantity including a non-linear effect from at least one transmitted signal of the wireless network, wherein at least one Base Station (BS) includes at least one antenna configured for data transmission, such that the BS is configured for wireless communication with a User Equipment (UE) in the wireless network, and the BS is configured to establish a link between the BS and the UE, to provide a plurality of transmitted and uplink data streams, the system comprising: a processing circuit, configured to implement receiver-side decoders, wherein at least one receiver-side decoder of the receiver-side decoders is configurable to provide a remotely configurable recovery of unknown symbols perturbed by the perturbation quantity, wherein the recovery is at a receiver-side and the perturbation is at the transmitter-side, such that the receiver is either for an uplink transmission at the BS or for a downlink transmission at the UE; and provide receiver-side decoding for symbol detection of symbol-dependent transmit-side perturbations by imposing a hierarchical signal model on the transmitted symbol, and wherein the decoding that is provided by the receiver-side decoders is used to recover the unknown symbols perturbed by the perturbation quantity and to identify symbol dependent perturbations, to reduce an amount of decoding processing costs by either the UE or the BS; and a control element in communication with the processing circuit to implement an action, based on the recovery of the unknown symbols perturbed by the perturbation quantity. ### Claim 12 (depends on 11) The system of claim 11, wherein the perturbation quantity includes one or a combination of non-linear impairments generated by non-linear characteristics of active devices, non-linear impairments generated by passive devices, non-linear impairments generated by harmonics in active devices or non-linear impairments generated by harmonics in passive devices. ### Claim 13 (depends on 11) The system of claim 11, wherein the hierarchical signal model on the transmitted symbol is a low-complexity symbol detection algorithm, that incorporates a hierarchical Gaussian mixture prior model. ### Claim 14 (depends on 13) The system of claim 13, wherein the hierarchical Gaussian mixture prior model is further imposed on the perturbed transmitted symbol to enforce a finite alphabet nature. ### Claim 15 (depends on 13) The system of claim 13, wherein the low-complexity symbol detection algorithm uses principles of variational Bayesian inference to develop a factorized or decoupled iterative detection algorithm. ### Claim 16 A method for processing a perturbation quantity received in a wireless network, the perturbation quantity including a non-linear effect from at least one transmitted signal of the wireless network, the method comprising: implementing receiver-side decoders, such that at least one receiver-side decoder of the receiver-side decoders is configurable for providing a configurable recovery of unknown symbols perturbed by the perturbation quantity, wherein the recovery is at a receiver-side and the perturbation is at the transmitter-side, such that the receiver is either for an uplink transmission at a base station (BS) or for a downlink transmission at a user equipment (UE); and providing receiver-side decoding for symbol detection of symbol-dependent transmit-side perturbations by imposing a hierarchical signal model on the transmitted symbol, and wherein the decoding that is provided by the receiver-side decoders is used to recover the unknown symbols perturbed by the perturbation quantity and to identify symbol dependent perturbations, to reduce an amount of decoding processing costs by either the UE or the BS, wherein a processing circuit is used to implement the method. ### Claim 17 (depends on 16) The method of claim 16, wherein the hierarchical signal model on the transmitted symbol is a low-complexity symbol detection algorithm, that incorporates a hierarchical truncated Gaussian mixture prior model, such that the hierarchical Gaussian mixture prior model is further imposed on the perturbed transmitted symbol to enforce a finite alphabet nature. ### Claim 18 (depends on 16) The method of claim 16, wherein steps to implement the hierarchical signal model include update the receiver-channel-based likelihood via decoupled GAMP; update the posterior of the effectively transmitted symbols which are truncated Gaussian variables with updated distribution parameters; update the posterior of precision variables which are independent Gamma variables with updated distribution parameters; update the posterior of label variables which are independent Bernoulli variables with updated distribution parameters; and update the model parameters (hyper-parameters) by finding the optimized perturbation to the recovered symbols.