Patent•
Low-complexity large-scale MIMO low-orbit satellite precoding method
15 Jan 2021-
TL;DR: In this paper, a low-complexity large-scale MIMO downlink precoding method was proposed for low-orbit satellite communication system, where a large scale uniform planar antenna array is configured on a satellite side, a satellite groups users by using space angle information of each user, and the users in the same group are scheduled to use the same time-frequency resource to perform wireless communication with the satellite.
Abstract: The invention provides a low-complexity large-scale MIMO downlink precoding method in a low-orbit satellite communication system, a large-scale uniform planar antenna array is configured on a satellite side, a satellite groups users by using space angle information of each user, and the users in the same group are scheduled to use the same time-frequency resource to perform wireless communicationwith the satellite. A downlink precoding vector of each user is calculated by utilizing the statistical channel state information at the satellite side. Based on a truncated Taylor polynomial expansion theory, complex large-dimension matrix inversion operation in a downlink precoding vector is replaced by the sum of finite term matrix polynomials, so that the calculation complexity of the precoding vector is reduced. A matrix polynomial is iteratively calculated by adopting a Horner algorithm in calculation, so that the calculation complexity of the matrix polynomial is reduced. The final sumrate performance of the method provided by the invention can effectively approach the performance of downlink maximum signal-to-leakage-and-noise ratio precoding at a low expansion order.
References
More filters
07 Jun 2020
TL;DR: A massive MIMO downlink transmission scheme with full frequency reuse (FFR) for LEO satellite communication systems by exploiting statistical channel state information (sCSI) at the transmitter and a closed-form low-complexity sCSI based DL precoder is developed.
Abstract: Low earth orbit (LEO) satellite communications are expected to be incorporated in future wireless networks to provide global wireless access with enhanced data rates. Massive multiple-input multiple-output (MIMO) techniques, though widely used in terrestrial communication systems, have not been applied to LEO satellite communication systems. In this paper, we propose a massive MIMO downlink (DL) transmission scheme with full frequency reuse (FFR) for LEO satellite communication systems by exploiting statistical channel state information (sCSI) at the transmitter. We first establish a massive MIMO channel model for LEO satellite communications and propose Doppler and time delay compensation techniques at user terminals (UTs). Then, we develop a closed-form low-complexity sCSI based DL precoder by maximizing the average signal-to-leakage-plus-noise ratio (ASLNR). Motivated by the DL ASLNR upper bound, we further propose a space angle based user grouping algorithm to schedule the served UTs into different groups, where each group of UTs use the same time and frequency resource. Numerical results demonstrate that the proposed massive MIMO transmission scheme with FFR significantly enhances the data rate of LEO satellite communication systems.
29 citations
Patent•
28 Oct 2009
TL;DR: In this paper, a distribution type space-time pre-coding transmission method based on channel angle domain information is proposed to obtain more accurate statistical information of the channel and reduce the required feedback amount.
Abstract: The invention discloses a distribution type space-time pre-coding transmission method based on channel angle domain information. A receiving terminal feeds back the channel angle domain information estimated by the channel comprising the average incidence angle, angle extension and normalization receiving antenna distance, to a transmitting terminal and after receiving the feedback information, the transmitting terminal firstly constructs the statistical information of the channel comprising the mean and correlation matrix and then designs the best pre-coding matrix using the information design and performing the pre-treatment of the space-time code word designed in advance. The distribution type space-time pre-coding transmission method based on channel angle domain information can obtain the more accurate statistical information of the channel and reduce the required feedback amount.
9 citations
Patent•
04 Mar 2021
TL;DR: In this article, a large-scale MIMO satellite mobile communication method and system is proposed, which comprises: a satellite or a gateway station grouping users to be served in a coverage area by using space angle information of each user to form a space division user group; user terminals in the same group communicating with the satellite by using the same time-frequency resource, and user users in different groups communicating with each satellite using different time-channel resources; for the user terminals, the satellite or the gateway station calculating a downlink precoding vector and an uplink receiving processing vector
Abstract: Disclosed are a large-scale MIMO satellite mobile communication method and system. The method comprises: a satellite or a gateway station grouping users to be served in a coverage area by using space angle information of each user to form a space division user group; user terminals in the same group communicating with the satellite by using the same time-frequency resource, and user terminals in different groups communicating with the satellite by using different time-frequency resources; for the user terminals in the same space division user group, the satellite or the gateway station calculating a downlink precoding vector and an uplink receiving processing vector that correspond to each user terminal by using statistical channel information of each user terminal, and then performing downlink precoding transmission and uplink receiving signal processing by using the obtained vectors; and the user terminal performing frequency and time compensation on a received signal and a sent signal by utilizing Doppler frequency shift caused by satellite movement and the minimum propagation time delay of long-distance propagation. According to the present invention, the spectral efficiency and the power efficiency of a satellite mobile communication system can be greatly improved, and the implementation complexity is reduced.
5 citations
Patent•
14 May 2019
TL;DR: In this paper, the authors present a method of operating a high throughput satellite with multiple modes of operation and transitions between them in response to the spectrum fill rate, which may include altering color re-use patterns to increase or reduce number of colors, using intra-beam geographic sub-division, or precoding downlink signals.
Abstract: A high throughput satellite and a method of operating a high throughput satellite. The satellite has multiple modes of operation and transitions between them in response to the spectrum fill rate. Modes of operation may include altering color re-use patterns to increase or reduce number of colors, using intra-beam geographic sub-division, or precoding downlink signals.
4 citations
Patent•
07 Dec 2018
TL;DR: In this paper, a network coding based multipath routing method of a double-layer satellite network is proposed, where a satellite network topology including double layer satellite constellation is determined according to relation between the number of satellites and the capacity of the satellite network; a network route is set according to the real-time sate of satellite network, availability weights of an inter-satellite link and satellite nodes along the way are calculated between a source end node and a target end node, and a local network routing state in response to a routing request is obtained according to availability weights;
Abstract: The invention discloses a network coding based multipath routing method of a double-layer satellite network The method comprises that a satellite network topology including double-layer satellite constellation is constructed, and a satellite network structure is determined according to relation between the number of satellites and the capacity of the satellite network; a network route is set according to the real-time sate of the satellite network, availability weights of an inter-satellite link and satellite nodes along the way are calculated between a source end node and a target end node,and a local network routing state in response to a routing request is obtained according to the availability weights; performance of the satellite communication network is optimized by combining network coding with multipath routing, and an effective link satisfying a service demand is established in the network; and according to a congestion condition of the satellite network as well as the availability weights of the satellite nodes and links therebetween, the throughput of the satellite network is improved Thus, ground users can be covered widely via the MEO/LED double-layer satellite network topology structure, and the data transmission performance of the satellite network is improved
3 citations