# US 12,004,069 B2 · Hybrid quantize-forward and decode-forward relaying transmission for massive MIMO HetNets > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,004,069 B2 - Document ID: US12004069B2 - Status: Granted - Kind: B2 - Application number: 17/614,727 - Filed: 2019-06-19 - Published: 2022-08-04 - Granted: 2024-06-04 - Earliest claimed: 2019-06-19 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Gary Boudreau; Ahmad Abu Al Haija; Min Dong; Ben Liang - Web page: https://patentgrep.com/patent/US12004069B2 ## CPC - H04W 40/22: using selective relaying for reaching a BTS [Base Transceiver Station] or an access point - H04B 7/022: Site diversity; Macro-diversity (using two or more spaced independent antennas H04B7/04) - H04B 7/0413: MIMO systems - H04B 7/15542: {Selecting at relay station its transmit and receive resources (selection of wireless resources by user or terminal H04W72/02; arrangements affording multiple use of the transmission path by two-dimensional division of the resources H04L5/0003, or by allocating sub-channels H04L5/003)} - H04B 7/15557: {Selecting relay station operation mode, e.g. between amplify and forward mode, decode and forward mode or FDD - and TDD mode} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION ## Abstract A method, network node and processor for processing uplink signals transmitted from a wireless device (WD) to provide a combination of quantize-forwarding and decode-forwarding relayed signals in massive multiple input multiple output (MIMO) heterogeneous networks (HetNets). According to one aspect, whether quantize-forwarding or decode-forwarding is used depends on a ratio of a quality of a WD signal received at a Small Cell Base Station (SCBS) to a quality of the WD signal received at a Macro Cell Base Station (MCBS). When the ratio is less than a first threshold, signals received at the SCBS may be quantize-forwarded to the MCBS and when the ratio exceeds a second threshold larger than the first threshold, signals received at the SCBS may be decode-forwarded to the MCBS. When the ratio lies between the first and second threshold, signals received at the SCBS may be quantize-forwarded to the MCB. ## Claims ### Claim 1 A method for processing uplink signals transmitted from a wireless device, WD, to a small cell base station, SCBS, and from the SCBS to a macro cell base station, MCBS, the MCBS serving a macro cell that at least partially includes a small cell served by the SCBS, the method comprising: for each of a plurality of WDs served by the SCBS: determining a ratio of signal quality of a signal received from the WD at the SCBS to a signal quality of a signal received from the WD at the MCBS; comparing the determined ratio to a first threshold; and when the ratio is less than the first threshold, forwarding the signal received at the SCBS to the MCBS as a quantize-forward, QF, relay signal; when the determined ratio is greater than the first threshold, comparing the determined ratio to a second threshold greater than the first threshold, and if the determined ratio is greater than the second threshold, forwarding the signal received at the SCBS to the MCBS as a decode-forward, DF, relay signal; and otherwise, forwarding the signal received at the SCBS to the MCBS as a QF relay signal. ### Claim 2 (depends on 1) The method of claim 1, wherein the second threshold is determined based at least in part on a linear threshold search of no more than K iterations, where K is the number of the plurality of WDs served by the SCBS. ### Claim 3 (depends on 1) The method of claim 1, wherein the second threshold is determined such that a number of WDs selected for DF relaying results in a maximum weighted sum rate of signals relayed from the SCBS to the MCBS. ### Claim 4 (depends on 1) The method of claim 1, further comprising determining a quantization for each WD signal forwarded by QF relaying, the quantization being determined by a water-filling algorithm. ### Claim 5 (depends on 4) The method of claim 4, further comprising determining a phase duration for each forwarded WD signal, the phase duration being determined by the water-filling algorithm. ### Claim 6 (depends on 4) The method of claim 4, wherein the water-filling algorithm includes: prioritizing the WDs based at least in part on weighting factors and on the determined ratio for each WD; determining a maximum transmit rate for each WD in order of priority; and determining phases of the WDs as a function of their maximum transmit rates. ### Claim 7 (depends on 1) The method of claim 1, wherein the forwarding is by a transmission process that includes binning the WD signals and transmitting binning indices that at least one of: include quantization indices of QF relay signals; and that correspond to decoded messages of the DF relay signals. ### Claim 8 (depends on 7) The method of claim 7, wherein the transmission process includes applying separate sequential sliding window decoding over two sequential transmission blocks received at the MCBS. ### Claim 9 (depends on 8) The method of claim 8, wherein the decoding at the MCBS includes decoding a signal from an nth WD sent in a first of the two transmission blocks by applying zero-forcing detection to separate data streams of the WDs and data streams of the SCBS. ### Claim 10 (depends on 8) The method of claim 8, wherein the decoding at the MCBS further includes decoding a bin index of the nth WD signal in the second transmission block using an nth phase and further decoding a message of the nth WD signal based at least in part on the bin index. ### Claim 11 A network node for processing uplink signals from a wireless device, WD, to a small cell base station, SCBS, and from the SCBS to a macro cell base station, MCBS, the MCBS serving a macro cell that at least partially includes a small cell served by the SCBS, the network node including processing circuitry configured to: for each of a plurality of WDs served by the SCBS: determine a ratio of signal quality of a signal received from the WD at the SCBS to signal quality of a signal received from the WD at the MCBS; compare the determined ratio to a first threshold; and when the ratio is less than the first threshold, forward the signal received at the SCBS to the MCBS as a quantize-forward, QF, relay signal; when the ratio is greater than the first threshold, compare the determined ratio to a second threshold greater than the first threshold and if the determined ratio is greater than the second threshold, forward the signal received at the SCBS to the MCBS as a decode-forward, DF, relay signal; and otherwise, forward the signal received at the SCBS to the MCBS as a QF relay signal. ### Claim 12 (depends on 11) The network node of claim 11, wherein the second threshold is determined based at least in part on a linear threshold search of no more than K iterations, where K is the number of the plurality of WDs served by the SCBS. ### Claim 13 (depends on 11) The network node of claim 11, wherein the second threshold is determined such that a number of WDs selected for DF relaying results in a maximum weighted sum rate of signals relayed from the SCBS to the MCBS. ### Claim 14 (depends on 11) The network node of claim 11, wherein the processing circuitry is further configured to determine a quantization for each WD signal forwarded by QF relaying, the quantization being determined by a water-filling algorithm. ### Claim 15 (depends on 14) The network node of claim 14, wherein the processing circuitry is further configured to determine a phase duration for each forwarded WD signal, the phase duration being determined by the water-filling algorithm. ### Claim 16 (depends on 14) The network node of claim 14, wherein the water-filling algorithm includes: prioritizing the WDs based at least in part on weighting factors and on the determined ratio for each WD; determining a maximum transmit rate for each WD in order of priority; and determining phases of the WDs as a function of their maximum transmit rates. ### Claim 17 (depends on 11) The network node of claim 11, wherein the forwarding is by a transmission scheme that includes binning the WD signals and transmitting binning indices that at least one of: include quantization indices of QF relay signals; and that correspond to decoded messages of the DF relay signals. ### Claim 18 (depends on 17) The network node of claim 17, wherein the transmission scheme includes applying separate sequential sliding window decoding over two sequential transmission blocks at the MCBS. ### Claim 19 (depends on 18) The network node of claim 18, wherein the decoding at the MCBS includes decoding a signal from an nth WD sent in a first of the two transmission blocks by applying zero-forcing detection to separate data streams of the WDs and data streams of the SCBS. ### Claim 20 (depends on 18) The network node of claim 18, wherein the decoding at the MCBS further includes decoding a bin index of the nth WD signal in the second transmission block using an nth phase and further decoding a message of the nth WD signal based at least in part on the bin index. ### Claim 21 A processor for processing uplink signals from a wireless device, WD, to a small cell base station, SCBS, and from the SCBS to a macro cell base station, MCBS, the MCBS serving a macro cell that at least partially includes a small cell served by the SCBS, the processor comprising: a ratio determiner configured to receive or determine a ratio of a signal quality of a signal received from the WD at the SCBS to a signal quality of a signal received from the WD at the MCBS; a first comparator configured to compare the ratio to a first threshold; a second comparator configured to compare the ratio to a second threshold; and a signal forwarder configured to forward the signal received at the SCBS to the MCBS as a quantize-forward, QF, relay signal when the ratio is less than the first threshold, as a QF relay signal when the ratio is greater than the first threshold but less than the second threshold, and as a decode-forward, DF, relay signal when the ratio is greater than the second threshold. ### Claim 22 (depends on 21) The processor of claim 21, wherein the second threshold is determined based at least in part on a linear threshold search of no more than K iterations, where K is a number of a plurality of WDs served by the SCBS. ### Claim 23 (depends on 21) The processor of claim 21, wherein the second threshold is determined such that a number of WDs selected for DF relaying results in a maximum weighted sum rate of signals relayed from the SCBS to the MCBS. ### Claim 24 (depends on 21) The processor of claim 21, further comprising a quantizer configured to determine a quantization for each WD signal forwarded by QF relaying, the quantization being determined by the quantizer using a water-filling algorithm. ### Claim 25 (depends on 24) The processor of claim 24, further comprising a phase duration determiner to determine a phase duration for each forwarded WD signal, the phase duration being determined by the phase duration determiner using the water-filling algorithm. ### Claim 26 (depends on 24) The processor of claim 24, wherein the water-filling algorithm includes: prioritizing the WDs based at least in part on weighting factors and on the determined ratio for each WD; determining a maximum transmit rate for each WD in order of priority; and determining phases of the WDs as a function of their maximum transmit rates. ### Claim 27 (depends on 21) The processor of claim 21, wherein the forwarding is by a transmission scheme that includes binning the WD signals and transmitting binning indices that at least one of: include quantization indices of QF relay signals; and that correspond to decoded messages of the DF relay signals. ### Claim 28 (depends on 27) The processor of claim 27, wherein the transmission scheme includes applying separate sequential sliding window decoding over two sequential transmission blocks at the MCBS. ### Claim 29 (depends on 28) The processor of claim 28, wherein the decoding at the MCBS includes decoding a signal from an nth WD sent in a first of the two transmission blocks by applying zero-forcing detection to separate data streams of the WDs and data streams of the SCBS. ### Claim 30 (depends on 28) The processor of claim 28, wherein the decoding at the MCBS further includes decoding a bin index of the nth WD signal in the second transmission block using an nth phase and further decoding a message of the nth WD signal based at least in part on the bin index.