Cohere Technologies, Inc.

Zte Corporation

Yoav Hebron

Ronny Hadani

Shlomo Selim Rakib

Michail Konstantinos Tsatsanis

Shachar Kons

Anton Monk

Christian Ibars Casas

Robert Fanfelle

James Delfeld

Jim Delfeld

Clayton Ambrose

Andreas Molisch

Orthogonal Time Frequency Space (OTFS) is a novel modulation scheme with significant benefits for 5G systems. The fundamental theory behind OTFS is presented in this paper as well as its benefits. We start with a mathematical description of the doubly fading delay-Doppler channel and develop a modulation that is tailored to this channel. We model the time varying delay-Doppler channel in the time-frequency domain and derive a new domain (the OTFS domain) where we show that the channel is transformed to a time invariant one and all symbols see the same SNR. We explore aspects of the modulation like delay and Doppler resolution, and address design and implementation issues like multiplexing multiple users and evaluating complexity. Finally we present some performance results where we demonstrate the superiority of OTFS.

Orthogonal time frequency space modulation techniques

Techniques for performing channel estimation in an orthogonal time, frequency and space (OTFS) communication system include receiving a wireless signal comprising a data signal portion and a pilot signal portion in which the pilot signal portion includes multiple pilot signals multiplexed together in the OTFS domain, performing two-dimensional channel estimation in a time-frequency domain based on a minimum mean square error (MMSE) optimization criterion, and recovering information bits using a channel estimate obtained from the two-dimensional channel estimation.

Channel acquisition using orthogonal time frequency space modulated pilot signals

Co-existence between an Orthogonal Time Frequency Space (OTFS) modulation system and a Long Term Evolution (LTE) system is achieved by generating a number of transmission beams for a first group of user equipment operating using LTE, and a second group of user equipment operating using the OTFS protocol, and transmitting a first group of data packets formatted according to the LTE protocol to the first group of user equipment and a second group of data packets formatted according to the OTFS protocol to the second group of user equipment. The transmissions are performed by precoding and modulating the first group of data packets according to an LTE modulation scheme, and precoding and modulating the second group of data packets according to an OTFS modulation scheme.

Co-existence of orthogonal time frequency space and long term evolution systems

Device, methods and systems for aspects of channel estimation for orthogonal time frequency space (OTFS) modulation in wireless systems are described. In an aspect, a method for wireless communication may include receiving, using multiple receive antennas, from a number of user devices, non-orthogonal pilots wherein at least some transmissions of the non-orthogonal pilots from different user devices overlap in at least some time and frequency resources, estimating individual pilots from the number of user devices by computing a pilot separation filter for each antenna, and estimating the wireless channel at time and frequency resources used by the non-orthogonal pilots by filtering the receiving signal at the multiple receiver antennas.

Aspects of channel estimation for orthogonal time frequency space modulation for wireless communications

Methods, systems and devices for providing transmission resources that achieve transmission diversity while reducing pilot signal overhead are described. An exemplary wireless communication method may be implemented in a wireless communication system in which transmission resources are allocated on a per physical resource block (PRB) basis, where a PRB corresponds to a two dimensional resource pattern comprising a first number of subcarriers along a frequency dimension and a second number time slots along a time dimension. The method includes logically dividing subcarriers in each PRB into an integer number of sub-groups of sub-carriers, wherein the integer number is greater than one, allocating, to a transmission, transmission resources corresponding to one or more of the sub-groups of subcarriers, performing the transmission in the wireless communication system.

Transmission resource allocation by splitting physical resource blocks

A method for performing downlink transmissions from a transmitting device to multiple user devices using transmission resources from a multi-dimensional grid of resources is described. The method includes logically partitioning the transmission resources into multiple segments, assigning, to a given user device of the multiple user devices, transmission resources of one or more of the multiple segments, and performing, using at least some of the assigned transmission resources for the given user device, a downlink transmission using an orthogonal time frequency space (OTFS) transformation on data or signals to be transmitted to the given user device.

Multi-user multiplexing of orthogonal time frequency space signals

Methods, systems and devices for providing transmission resources that achieve transmission diversity while reducing pilot signal overhead are described. An exemplary wireless communication method may be implemented in a wireless communication system in which transmission resources are allocated on a per physical resource block (PRB) basis, where a PRB corresponds to a two dimensional resource pattern comprising a first number of subcarriers along a frequency dimension and a second number time slots along a time dimension. The method includes logically dividing subcarriers in each PRB into an integer number of sub-groups of subcarriers, wherein the integer number is greater than one, allocating, to a transmission, transmission resources corresponding to one or more of the sub-groups of subcarriers, performing the transmission in the wireless communication system.

A method of reducing peak to average power ratio of uplink transmission includes, assigning a slice of transmission resource to uplink transmission from a user equipment, where all resource elements in the slice have a same Doppler value, mapping data to the slice, performing orthogonal time frequency space transformation to generate time-frequency domain data and processing the time-frequency domain data for transmission.

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Santa Clara, CA, United States of America

Yoav Hebron