# US 7,609,774 B2 · Beamforming transceiver architecture with enhanced channel estimation and frequency offset estimation capabilities in high throughput WLAN systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,774 B2 - Document ID: US7609774B2 - Status: Granted - Kind: B2 - Application number: 11/314,859 - Filed: 2005-12-20 - Published: 2007-06-21 - Granted: 2009-10-27 - Earliest claimed: 2005-12-20 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Jyh Chau Horng; Chiu Ngo - Web page: https://patentgrep.com/patent/US7609774B2 ## CPC - H04L 27/0014: {Carrier regulation (of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657)} - H04L 1/06: using space diversity - H04L 25/0248: {Eigen-space methods} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method and system for transmitting bit streams in a telecommunication system, by combining a bit stream with a first portion of a preamble, applying power loading to the combined bit stream, applying eigen-steering to the power loaded bit stream, and combining a second portion of the preamble with the eigen-steered bit stream for transmission. The first portion of the preamble includes an HT preamble, and the second portion of the preamble includes a legacy preamble. ## Claims ### Claim 1 A method of transmitting an information signal stream in a telecommunication system, comprising: in a wireless communication: combining a bit stream with a first portion of a preamble; applying power loading to the combined bit stream; applying eigen-steering to the power loaded bit stream; and combining a second portion of the preamble with the eigen-steered bit stream for transmission. ### Claim 2 (depends on 1) The method of claim 1 wherein the first portion of the preamble comprises a high throughput (HT) preamble. ### Claim 3 (depends on 2) The method of claim 2 wherein the second portion of the preamble comprises a legacy preamble. ### Claim 4 (depends on 2) The method of claim 2 wherein the HT preamble allows fine automatic gain control and fine frequency offset estimation. ### Claim 5 (depends on 2) The method of claim 2 wherein the transmitted signal or HT portion of the preamble is expressed as: X=VPS wherein V represents eigen-steering function, P represents power loading, and S represents coded data streams. ### Claim 6 (depends on 5) The method of claim 5 further comprising transmitting multiple bit streams via a plurality of transmission antennas, wherein: X comprises a Nt×1 vector for each transmitted bit stream; V comprises a Nt×Nss steering matrix; P comprises a Nss×Nss diagonal power-loading matrix; S comprises a Nss×1 vector for each input bit stream; Nt represents the number of transmit antennas; and Nss represents the number of bit streams. ### Claim 7 (depends on 6) The method of claim 6 wherein a transmission channel is defined by a channel matrix H, such that the eigen-steering matrix V is a function of the right singular matrix of the channel matrix H as: H=UDVH wherein D is a Nss×Nss diagonal matrix with channel eigenvalues along the diagonal; (.)H is the Hermitian operation; U comprises a Nr×Nss matrix which is used as a steering matrix at a receiver. ### Claim 8 (depends on 7) The method of claim 7 further comprising: receiving a transmitted signal in the receiver having Nr receive antennas, wherein the channel matrix H comprises a Nr×Nt matrix, such that with an additive noise n at the receiver, the received signal is expressed as: Y=HX+n=UDVH·VPS+n=UDPS+n={tilde over (H)}S+n where {tilde over (H)}=U(DP)=UD′, where n represents noise, {tilde over (H)} represents an estimated channel, and D′ represents a diagonal matrix. ### Claim 9 (depends on 8) The method of claim 8 wherein S is replaced by the HT preamble symbols and the matrix U and the matrix D′ are computed by U-D decomposing the matrix {tilde over (H)}, such that the estimated channel matrix based on the received HT preamble is {tilde over (H)}. ### Claim 10 (depends on 3) The method of claim 3 further comprising receiving the transmission in a receiver, and performing coarse AGC and frequency offset estimation based on the legacy preamble, and fine AGC and frequency offset estimation based on the HT preamble. ### Claim 11 (depends on 1) The method of claim 1 wherein the telecommunication system comprises a wireless orthogonal frequency division multiplexing (OFDM) system. ### Claim 12 (depends on 1) The method of claim 1 further comprising: transmitting multiple bit streams via multiple channels over a plurality of transmit antennas. ### Claim 13 (depends on 12) The method of claim 12 further comprising: obtaining channel condition for each channel; determining said power loading per channel according to channel condition; and transmitting the bit streams via said multiple channels over the plurality of transmit antennas according to the power loading per channel. ### Claim 14 (depends on 1) The method of claim 1, wherein the wireless communication device comprises a wireless transmitter. ### Claim 15 (depends on 14) The method of claim 14, wherein the wireless transmitter includes a processor coupled to a memory. ### Claim 16 A telecommunication system for transmitting an information signal stream, comprising: a transmitter including a first combiner for combining a bit stream with a first portion of a preamble, a controller for applying power loading to the combined bit stream, a eigen-steering unit for applying eigen-steering to the power loaded bit stream, and a second combiner for combining a second portion of the preamble with the eigen-steered bit stream for transmission. ### Claim 17 (depends on 16) The system of claim 16 wherein the first portion of the preamble comprises a high throughput (HT) preamble. ### Claim 18 (depends on 16) The system of claim 16 wherein the second portion of the preamble comprises a legacy preamble. ### Claim 19 (depends on 17) The system of claim 17 wherein the HT preamble allows fine automatic gain control and fine frequency offset estimation. ### Claim 20 (depends on 17) The system of claim 17 wherein the transmitted signal or HT portion of the preamble is expressed as: X=VPS wherein V represents eigen-steering function, P represents power loading, and S represents coded data streams. ### Claim 21 (depends on 20) The system of claim 20 wherein the transmitter transmits multiple bit streams via a plurality of transmission antennas, wherein: X comprises a Nt×1 vector for each transmitted bit stream; V comprises a Nt×Nss steering matrix; P comprises a Nss×Nss diagonal power-loading matrix; S comprises a Nss×1 vector for each input bit stream; Nt represents the number of transmit antennas; and Nss represents the number of bit streams. ### Claim 22 (depends on 21) The system of claim 21 wherein a transmission channel is defined by a channel matrix H, such that eigen-steering matrix function V is a function of the right singular matrix of the channel matrix H as: H=UDVH wherein D is a Nss×Nss diagonal matrix with channel eigenvalues along the diagonal; (.)H is the Hermitian operation; U comprises a Nr×Nss matrix which is used as a steering matrix at a receiver. ### Claim 23 (depends on 22) The system of claim 22 wherein the receiver is configured for receiving a transmission signal from the transmitter, the receiver having Nr receive antennas, wherein the channel H comprises a Nr×Nt matrix, such that with the additive noise n at the receiver, the received signal is expressed as: Y=HX+n=UDVH·VPS+n=UDPS+n={tilde over (H)}S+n where {tilde over (H)}=U(DP)=UD′, where n represents noise, {tilde over (H)} represents an estimated channel, and D′ represents a diagonal matrix. ### Claim 24 (depends on 23) The system of claim 23 wherein S is replaced by the HT preamble symbols and the matrix U and the matrix D′ are computed by U-D decomposing the matrix {tilde over (H)}, such that the estimated channel matrix based on the received HT preamble is {tilde over (H)}. ### Claim 25 (depends on 16) The system of claim 16 wherein the telecommunication system comprises a wireless orthogonal frequency division multiplexing (OFDM) system. ### Claim 26 (depends on 16) The system of claim 16 wherein the transmitter transmits multiple bit streams via multiple channels over a plurality of transmission antennas, and further obtains channel condition for each channel, determines said power loading per channel according to channel condition, and transmits the bit streams via said multiple channels over the plurality of transmit antennas according to the power loading per channel. ### Claim 27 (depends on 18) The system of claim 18 further comprising a receiver that receives the transmission and performs coarse AGC and frequency offset estimation based on the legacy preamble, and fine AGC and frequency offset estimation based on the HT preamble.