A study on precoding control scheme for uplink MIMO in LTE-Advanced
11 Dec 2008-Vol. 108, Iss: 358, pp 55-60
About: The article was published on 2008-12-11 and is currently open access. It has received 3 citations till now. The article focuses on the topics: Spatial multiplexing & Precoding.
Citations
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23 Jun 2010TL;DR: In this article, a base station apparatus (200) is characterized by having a precoding weight/rank number selecting section (232) that determines rank information associated with the number of layers of spatial multiplexing in uplink, while determining a control amount of a transmission phase and/or transmission amplitude used in weighting for transmission antennas of a user apparatus.
Abstract: To suitably transmit feedback information for rank adaptation and precoding in uplink MIMO transmission to a user apparatus as feedback, a base station apparatus (200) is characterized by having a precoding weight/rank number selecting section (232) that determines rank information associated with the number of layers of spatial multiplexing in uplink, while determining a control amount of a transmission phase and/or transmission amplitude used in weighting for transmission antennas of a user apparatus, and transmission/reception sections (206a) (206b) that transmit the rank information determined in the precoding weight/rank number selecting section (232) to a mobile station (100) using an RRC signal, while transmitting the control amount to the mobile station (100) using a control channel signal.
9 citations
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23 Jun 2010TL;DR: In this article, a method of feeding-back information for rank adaptation and pre-coding in an upward-link MIMO transmission is provided, wherein feedback information for the rank adaptation is fed back appropriately to user devices.
Abstract: Provided is a method of feeding-back information, wherein feedback information for rank adaptation and pre-coding in an upward-link MIMO transmission is fed back appropriately to user devices. A base station device (200) is characterized in determining rank information that corresponds to the number of spatial multiplexing layers in an upward link, and in being provided with: a pre-coding-weighting/number-of-ranks selecting unit (232) that determines the control-amount for the transmission phase and/or the transmission amplitude to be used in weighting the transmission antennas of the user devices; and transmission-reception units (206a, 206b) that transmit rank information determined by this pre-coding-weighting/number-of-ranks selecting unit (232) to mobile stations (100), as an RRC signal, and that also transmits the control-amount to the mobile stations (100), as a control channel signal.
6 citations
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15 May 2011
TL;DR: The results clarifies that the estimation accuracy of MIMO channel responses using the SRS has a greater influence on modulation and coding scheme (MCS) selection for AMC than PV selection due to that fact that the throughput performance employing AMC is clearly degraded by approximately 20% while the block error rate for Rank-1 closed-loop transmit diversity is not degraded very much.
Abstract: This paper presents the laboratory experimental results employing LTE-Advanced testbed for the evaluation of the throughput performance of closed-loop single-user MIMO transmission at the uplink single carrier (SC)-FDMA radio access in LTE-Advanced. The throughput evaluation includes the impact of estimation accuracy of MIMO channel responses which are derived from the standardized sounding reference signal (SRS) and used for the precoding vector (PV) selection and adaptive modulation and coding (AMC) at the base station. The experimental results elucidate that the throughput of 200 Mbps is achieved by using 2-by-2 spatial multiplexing and carrier aggregation with 2 component carriers at the average received signal-to-noise power ratio of 34 dB when the transmission power ratio of SRS to data channel, PSRS, is set to ?{5 dB. The results also clarifies that the estimation accuracy of MIMO channel responses using the SRS has a greater influence on modulation and coding scheme (MCS) selection for AMC than PV selection due to that fact that the throughput performance employing AMC is clearly degraded by approximately 20% while the block error rate for Rank-1 closed-loop transmit diversity is not degraded very much when the PSRS is reduced from 0 dB to iV10 dB.
5 citations
Cites methods from "A study on precoding control scheme..."
...Therefore, the estimation accuracy of MIMO channel responses using SRS, which depends on the transmission interval and power for SRS, is important for the performance of closed-loop SUMIMO transmissions although former reports such as [8,9] assume the ideal estimation accuracy....
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...In LTE-Advanced uplink, single-user (SU)-MIMO employing codebook based closed-loop precoding is applied as well as the downlink [8,9]....
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