# US 11,985,011 B2 · Distributed minimum mean-square error interference rejection combining (MMSE-IRC) processing for radio access networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,985,011 B2 - Document ID: US11985011B2 - Status: Granted - Kind: B2 - Application number: 17/130,940 - Filed: 2020-12-22 - Published: 2021-04-15 - Granted: 2024-05-14 - Earliest claimed: 2020-07-07 - Assignees: Intel Corporation - Applicants: Intel Corporation - Inventors: Alexei Davydov; Victor Sergeev; Bishwarup Mondal - Web page: https://patentgrep.com/patent/US11985011B2 ## CPC - H04L 25/021: {Estimation of channel covariance} - H04L 25/03006: {Arrangements for removing intersymbol interference} - H04B 1/12: Neutralising, balancing, or compensation arrangements - H04B 17/345: Interference values ({signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]} H04B17/336) - H04J 11/005: {of intercell interference} - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04L 25/0258: {Channel estimation using zero-forcing criteria} - H04W 72/541: using the level of interference - H04L 25/0204: {of multiple channels} - H04L 2025/03426: {transmission using multiple-input and multiple-output channels} - H04L 2025/03624: {Zero-forcing} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Various embodiments herein provide techniques for minimum mean-square error interference rejection combining (MMSE-IRC) processing of a received signal, distributed between a baseband unit (BBU) and a remote radio unit (RRU). The RRU may perform a first phase of processing based on an extended channel that includes a channel of one or more user equipments (UEs) served by the RRU and interference samples that correspond to other cells or additive noise. The first phase may include scaling the interference samples by a scaling coefficient to obtain a modified extended channel, and performing maximum ratio combining (MRC) on the modified extended channel to obtain a processed signal. The RRU may send the processed signal to the BBU for the second phase of processing. The second phase of processing may include regularized zero forcing to remove interference. Other embodiments may be described and claimed. ## Claims ### Claim 1 One or more non-transitory computer-readable media (NTCRM) having instructions stored thereon, that when executed by one or more processors cause a remote radio unit (RRU) to: receive a signal associated with an extended channel that includes a channel of one or more user equipments (UEs) served by the RRU and interference samples that correspond to other cells or additive noise; scale the interference samples by a scaling coefficient to obtain a modified extended channel; perform maximum ratio combining (MRC) of the received signal based on the modified extended channel to obtain a processed signal, wherein the MRC is performed using a different granularity for measurements of the channel than for measurements of the interference samples; and transmit the processed signal to a baseband unit (BBU) via a fronthaul link. ### Claim 2 (depends on 1) The one or more NTCRM of claim 1, wherein the processed signal is quantized before transmission to the BBU, and wherein a number of quantization bits in the processed channel is based on a value of the scaling coefficient. ### Claim 3 (depends on 1) The one or more NTCRM of claim 1, wherein the RRU is to obtain the modified extended channel according to: He=[H√{square root over (1−α)}Z], wherein He is the modified extended channel; H is the channel; α is the scaling coefficient; and Z is an interference sample matrix that corresponds to the interference samples. ### Claim 4 (depends on 3) The one or more NTCRM of claim 3, wherein the RRU is to perform the MRC according to: H e H = [ H H 1 - α ⁢ Z H ] ⁢ wherein HeH denotes a Hermitian Transpose of He. ### Claim 5 (depends on 1) The one or more NTCRM of claim 1, wherein the instructions, when executed, are further to cause the RRU to receive a message from the BBU to indicate a requested value of the scaling coefficient. ### Claim 6 (depends on 1) The one or more NTCRM of claim 1, wherein the scaling of the interference samples and MRC based on the extended channel are included in a first phase of processing, and wherein the processed signal is transmitted to the BBU for a second phase of processing that includes regularized zero-forcing to suppress intra-cell or inter-cell interference. ### Claim 7 (depends on 6) The one or more NTCRM of claim 6, wherein the first and second phases combine to provide processing based on covariance matrix estimation including a linear combination of a sample covariance matrix and a structured covariance matrix. ### Claim 8 One or more non-transitory computer-readable media (NTCRM) having instructions stored thereon, that when executed by one or more processors cause a baseband unit (BBU) to: receive a processed signal from a remote radio unit (RRU) after a first phase of processing that includes maximum ratio combining (MRC) of a modified extended channel, wherein the modified extended channel includes a received signal on a channel of one or more user equipments (UEs) served by the RRU and interference samples that correspond to other cells or additive noise are scaled by a scaling coefficient; perform a second phase of processing on the processed signal to generate an output signal, wherein the second phase includes regularized zero forcing, wherein the second phase of processing includes a first matrix inversion based on the interference samples and a second matrix inversion based on the channel of the one or more UEs, and wherein the first matrix inversion is performed with a larger granularity in the time or frequency domain than the second matrix inversion; and provide the output signal to a signal decoder to decode data in the output signal. ### Claim 9 (depends on 8) The one or more NTCRM of claim 8, wherein the regularized zero forcing is performed according to: ( H e H ⁢ H e + α ⁢ tr ⁡ ( S ) L ⁢ I ) - 1 wherein HeH is the processed signal, He is the channel of the one or more UEs, α is the scaling coefficient, tr is a trace function, S is a sample covariance matrix, L is a number of elements in the received processed signal, and I is an identity matrix. ### Claim 10 (depends on 9) The one or more NTCRM of claim 9, wherein the sample covariance matrix, S, is determined according to: S = 1 L - M ⁢ ∑ k = 1 L - M ⁢ z k · z k H ; wherein M is a number of elements in the output signal, and zk is a vector that corresponds to the interference samples. ### Claim 11 (depends on 8) The one or more NTCRM of claim 8, wherein the instructions, when executed, are further to cause the BBU to receive, from the RRU, one or more parameters used by the RRU for the first phase of processing, wherein the second phase of processing is performed based on the one or more parameters. ### Claim 12 (depends on 11) The one or more NTCRM of claim 11, wherein the one or more parameters include the scaling coefficient. ### Claim 13 (depends on 8) The one or more NTCRM of claim 8, wherein the instructions, when executed, are further to cause the BBU to send a message to the RRU to indicate a requested value of the scaling coefficient. ### Claim 14 (depends on 13) The one or more NTCRM of claim 13, wherein the instructions, when executed, are further to cause the BBU to determine the requested value based on one or more of a processing load or a processing capability of the BBU. ### Claim 15 An apparatus to be implemented in a remote radio unit (RRU), the apparatus comprising: radio frequency (RF) interface circuitry; and processor circuitry coupled to the RF interface circuitry, the processor circuitry to: receive, via the RF interface, a signal associated with an extended channel that includes a channel of one or more user equipments (UEs) served by the RRU and interference samples that correspond to other cells or additive noise; scale the interference samples by a scaling coefficient to obtain a modified extended channel; perform maximum ratio combining (MRC) based on the modified extended channel to obtain a processed signal, wherein the processed signal has fewer elements than the received signal associated with the extended channel; quantize the processed signal to obtain a quantized signal, wherein a number of quantization bits in the quantized channel is based on a value of the scaling coefficient; and transmit the quantized signal to a baseband unit (BBU) via the RF interface circuitry. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the processor circuitry is to perform the MRC with a different granularity for measurements of the channel than for measurements of the interference samples. ### Claim 17 (depends on 15) The apparatus of claim 15, wherein the modified extended channel is obtained according to: He=[H√{square root over (1−α)}Z], wherein He is the modified extended channel; H is the channel; α is the scaling coefficient; and Z is an interference sample matrix that corresponds to the interference samples. ### Claim 18 (depends on 17) The apparatus of claim 17, wherein the MRC is performed according to: H e H = [ H H 1 - α ⁢ Z H ] wherein HeH denotes a Hermitian Transpose of He. ### Claim 19 (depends on 15) The apparatus of claim 15, wherein the processor circuitry is further to receive a message from the BBU to indicate a requested value of the scaling coefficient. ### Claim 20 (depends on 15) The apparatus of claim 15, wherein the processing circuitry is further to send, to the BBU, one or more parameters used by the RRU to determine the quantized signal. ### Claim 21 (depends on 15) The apparatus of claim 15, wherein the scaling of the interference samples and MRC based on the extended channel are included in a first phase of processing, and wherein the quantized channel is transmitted to the BBU for a second phase of processing that includes regularized zero-forcing to suppress intra-cell or inter-cell interference. ### Claim 22 One or more non-transitory computer-readable media (NTCRM) having instructions stored thereon, that when executed by one or more processors cause a remote radio unit (RRU) to: receive a signal associated with an extended channel that includes a channel of one or more user equipments (UEs) served by the RRU and interference samples that correspond to other cells or additive noise; scale the interference samples by a scaling coefficient to obtain a modified extended channel; perform maximum ratio combining (MRC) of the received signal based on the modified extended channel to obtain a processed signal; and transmit the processed signal to a baseband unit (BBU) via a fronthaul link; wherein the processed signal is quantized before transmission to the BBU, and wherein a number of quantization bits in the processed channel is based on a value of the scaling coefficient. ### Claim 23 (depends on 22) The one or more NTCRM of claim 22, wherein the instructions, when executed, are further to cause the RRU to receive a message from the BBU to indicate a requested value of the scaling coefficient. ### Claim 24 (depends on 22) The one or more NTCRM of claim 22, wherein the scaling of the interference samples and MRC based on the extended channel are included in a first phase of processing, and wherein the processed signal is transmitted to the BBU for a second phase of processing that includes regularized zero-forcing to suppress intra-cell or inter-cell interference. ### Claim 25 One or more non-transitory computer-readable media (NTCRM) having instructions stored thereon, that when executed by one or more processors cause a baseband unit (BBU) to: receive a processed signal from a remote radio unit (RRU) after a first phase of processing that includes maximum ratio combining (MRC) of a modified extended channel, wherein the modified extended channel includes a received signal on a channel of one or more user equipments (UEs) served by the RRU and interference samples that correspond to other cells or additive noise are scaled by a scaling coefficient; receive, from the RRU, an indication of one or more parameters used by the RRU for the first phase of processing, wherein the one or more parameters include the scaling coefficient; perform a second phase of processing on the processed signal to generate an output signal, wherein the second phase includes regularized zero forcing, and wherein the second phase is performed based on the one or more parameters; and provide the output signal to a signal decoder to decode data in the output signal. ### Claim 26 (depends on 25) The one or more NTCRM of claim 25, wherein the instructions, when executed, are further to cause the BBU to send a message to the RRU to indicate a requested value of the scaling coefficient. ### Claim 27 (depends on 26) The one or more NTCRM of claim 26, wherein the instructions, when executed, are further to cause the BBU to determine the requested value based on one or more of a processing load or a processing capability of the BBU. ### Claim 28 (depends on 25) The one or more NTCRM of claim 25, wherein the regularized zero forcing is performed according to: ( H e H ⁢ H e + α ⁢ t ⁢ r ⁡ ( S ) L ⁢ I ) - 1 wherein HeH is the processed signal, He is the channel of the one or more UEs, α is the scaling coefficient, tr is a trace function, S is a sample covariance matrix, L is a number of elements in the received processed signal, and I is an identity matrix.