DE10333514(A1).pdf DE10333514(B4).pdf ====== EP1458156-A3 ====== * EP1458156(A2,A3).pdf * US20040174937(A1).pdf Transmission using Tomlinson-Harashima precoding Gottfried Ungerboeck The author proposes to use TH algorithm for zero excess bandwidth modulation in a wire transmission. ====== EP1647118-B1 ====== * EP1647118(B1).pdf * US20060198459(A1).pdf * WO2005011219(A1).pdf Nonlinear Precoding Method For A Digital Broadcast Channel Robert Fisher, Christoph Windpassinger The authors propose a non-linear precoding method based on modulo arithmetic for pre-equalisation on a digital broadcast channel. Several users are served simultaneously. By factorizing the channel matrix into a residual interference matrix containing only 1 value on the main diagonal and all the other elements are row-wise integral multiples of the signal constellation used and a reduced channel matrix, they provide a way to reduce crosstalk between users. This scheme is more relevant in a MU-MIMO context. ====== US7154957-B1 ====== * US7154957(B1).pdf Power spectrum shaping to reduce interference effects in devices sharing a communication devices Anton Monk, Edward Warner, Itzhak Gurantz, Ladd Elwardani, Ron Porat The authors propose to transmit a signal with a shaped power spectrum to minimize interference with devices that share the same communication medium(in particular coaxial wire transmission, in the context of cable settop-box). However, their apparatus looks like an iterative waterfilling algorithm for to shape the transmit power on sub-bands ====== WO2006021224-A1 ====== * WO2006021224(A1).pdf Precoder and method for precoding an input sequence to obtain a transmit sequence Katsutoshi Kusume The authors propose tan efficient precoding scheme which prevent intersymbol interference in a MIMO downlink context. They use a permuter for reordering input sequences and a predistroter for compensating interference. The precoder design is based on a Cholesky factorization which aims to setup the forward filter and also the feed-back filter. ====== WO2006048037-A1 ====== * WO2006048037(A1).pdf Multiuser transmission system Gerhard Bauch, Pedro Tejera The authors propose a downlink precoding scheme based on block-diagonalization. I.e each user precoding vector is chosen in the kernel of the channel matrix form other users. This scheme assumes that each subcarrier uses a different precoding vector. In the patent, the scheme is compared to standard DPC techinques ====== ieeecom.hochwald05-1 ====== A Vector-Perturbation Technique for Near-Capacity Multiantenna Multiuser Communication - Part I: Channel Inversion and Regularization Bertrand M. Hochwald, Christian B. Peel, A. Lee Swindlehurst ieeecom, vol 53, no 1, jan 2005 ====== ieeecom.hochwald05-2 ====== A Vector-Perturbation Technique for Near-Capacity Multiantenna Multiuser Communication - Part II: Perturbation Bertrand M. Hochwald, Christian B. Peel, A. Lee Swindlehurst ieeecom, vol 53, no 3, march 2005 The authors sudy channel inversion precoding in a multi-user context. they introduce regularization to improve the condition of the inverse and maximize the SINR at the receivers. Regularization enables linear growth and works especially well at low SNRs, but to achieve near-capacity performance they propose to add a perturbation to reduce the energy of the transmitted signal. This scheme in a regularized version of the ZF sphere encoder. ====== WO2007061416-A1 ====== * WO2007061416(A1).pdf Joint optimization of linear pre-filtering and nonlinear vector perturbation for MIMO mmultiuser precoding Jianzhong Zhang The author propose to jointly optimization the precoding matrix and the vector perturbation to minimize the transmission power at the transmitter side by first solving the ZF case since the optimization problem is not reparable in the MMSE case then he simplifies it by splitting the search on the precoding matrix into 3 structured matrices (one diagonal, one upper triangular and an unitary matrix) . This scheme is also an other version of the regularized ZF sphere encoder.