LTE TDD RRM Overview

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LTE TDD RRM Overview

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LTE TDD RRM Overview

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LTE TDD RRM Overview

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LTE TDD RRM Overview

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PMI

- Single stream: 4 matrices (2x1)

- Dual stream: 2 matrices (2x2)

# streams OL CL

1 “TxDiv” “SM single stream”

2 “SM” “SM dual stream”

LTE TDD RRM Overview

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LTE TDD RRM Overview

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LTE TDD RRM Overview

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LTE493 & LTE541 UE specific channel sounding via SRS used for UL channel estimation => consecutive generation of DL weights for PDSCH and dedicated reference signal (DRS)

RL25: per cell either LTE493 or LTE541 activated => also LTE493 supported

LTE TDD RRM Overview

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LTE TDD RRM Overview

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LTE898 introduced in RL35TD provides handover from TDD LTE to TD-SCDMA technology

Feature is very similar to LTE54 Inter-RAT handover to WCDMA as TD-SCDMA and WCDMA are respectively one of the two modes of operation of UTRA access technology

Handover to TD-SCDMA and WCDMA has separately different market and currently there isn’t any deployment of TD-SCDMA and WCDMA for the same operator

• When crossing the edge of LTE coverage the data call is no longer dropped but maintained in TD-SCDMA

• Feature allows to reduce the negative effect of potentially limited LTE coverage during its initial rollout

LTE TDD RRM Overview

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•First Multi-User MIMO feature in Nokia LTE release

• LTE1169 “DL TM8 based Dual User Single Layer Multi User MIMO” allows to transmit signal to 2 users on the same time and frequency resources simultaneously by using spatial multiplexing

•Feature uses 3GPP Transmission Mode 8 (TM8)

•LTE1169 reuses RL25 LTE541 “Single User Dual Layer Beamforming” feature for multi-user transmission. 3GPP Rel. 9 compliant UEs are required.

•According to system level simulations, average cell throughput gain of up to 10%, cell edge throughput gain up to 63% (simulation results)

•Neither cell peak throughput nor UE peak throughput is not impacted with LTE1169 feature

•UEs will be multiplexed if their correlation is low and they report sufficiently high CQI

•Only Single Layer beamformed UEs are multiplexed. Dual Layer beamformed UEs are not affected

LTE TDD RRM Overview

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LTE TDD RRM Overview

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• LTE 1558 Carrier Aggregation is the flagship RL45TD feature that brings into life the LTE Advanced concept (as standardized in 3GPP Rel. 10) in the NSN TD-LTE product

• It is a counterpart to the available FDD features:

• LTE1089 DL Carrier Aggregation 20 MHz (RL50)

• LTE1332 DL Carrier Aggregation 40 MHz (RL60)

• LTE1558 implements certain existing FDD functionalities of LTE1089 and LTE1332 in TD-LTE (with some TD-specific adjustments)

• Primary aim of the feature is to boost mean and peak user throughput via sending the user data simultaneously over two carriers

• Maximum achievable peak user throughput could be doubled in contrast to non-CA case

• To make the aggregation of carriers possible, regular cell is paired with additional logical cell serving the same geographical site sector.

• This dependency could be bi-directional – this first cell could play a role of secondary cell as well.

• LTE 1558 supports only intra-band carrier aggregation for 20 MHz + 20 MHz channel bandwidths

• Only non-GBR data could be sent via secondary cell (SCell)

• DL GBR data is sent via primary cell (PCell) only

• All cells handling CA UEs serve simultaneously also regular, non-CA UEs

• There is no carrier aggregation in the uplink direction

LTE TDD RRM Overview

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Note:

Carrier 1 could play a role of primary cell or secondary one. Similarly, Carrier 2 could be primary or secondary cell – in the context of Carrier Aggregation configuration

LTE TDD RRM Overview

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This feature is only supported with FSMF

• CoMP cannot be done across FSPs

• Max CoMP set size is 3

• CoMP is currently only supported within an eNB, Intra eNB CoMP

• Each cell is only listed in a single CoMP set.

• IRC should be selected for UL combining

• Due to the fact that the feature LTE614 Distributed Sites is not supported together with this feature, the maximum distance between the FSM and the RF module is limited to 200 meters (see also LTE94 Feederless site). This is the only limiting factor for the placement of the RF units

• From the network perspective the eNB is the only RAN network element that is impacted from this feature.

• Upto 9 CoMP sets can be defined as the maximum number of cells supported is 18

• The eNB does not raise an alarm due to broken Rx antenna as the functionality is not supported yet (feature LTE445 "Antenna Alarm with Rx Signal Comparison" is in RL70).In case both Tx- and Rx-branch of a cell are mapped to the same physical antenna, the eNB does rise an alarm due to detected Tx antenna failure. However, the eNB shall shutdown a cell with broken Tx antenna unless the management parameter txPathFailureMode has value 'keepCellInService'.

• Since the UL control information (UCI) is multiplexed into the PUSCH in time and frequency domain, there is no difference between the UL-SCH coming along with the PUSCH and the UCI coming along with the PUSCH. So this means that also the UCI on PUSCH benefits from the combining gain using the received signal from the antennas of the selected neighboring cell. So this means that the CQI, Ack/Nack, PMI and rank coming along on the PUSCH will have improved performance if this feature is enabled.

LTE TDD RRM Overview

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LTE TDD RRM Overview

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LTE TDD RRM Overview

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LTE TDD RRM Overview

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