N9080A LTE FDD and N9082A LTE TDD Measurement Applications X-Series Advanced Measurement Applications

Demo Guide

Introduction

The Keysight Technologies, Inc. N9080A and N9082A LTE measurement applications provide LTE FDD and TDD signal analysis with hardkey/softkey manual user interface and familiar SCPI programming.

Accelerate Your Time to Market with the LTE Measurement Application

The complexity of LTE systems requires signal analysis with in-depth modulation analysis as well as RF power measurements.

The Keysight X-Series signal analyzers (PXA/MXA/EXA), in combination with the N9080A LTE FDD and N9082A LTE TDD measurement applications, measure complex LTE signals with world-class accuracy and repeatability.

Its hardkey/softkey manual user interface plus SCPI programming capability is ideal for speedy design validation and/or early manufacturing.

High-quality modulation analysis measurement for both FDD and TDD frame structure signals according to 3GPP TS 36.211 v 8.6.0 (2009-03)

- Support for all TDD uplink-downlink configurations (0-6) and special subframe lengths (0-8)

- Downlink (OFDMA) and uplink (SC-FDMA) measurement capability in a single option

- All uplink and downlink channels and signals plus all bandwidths and modulation formats

- Comprehensive transmit signal quality measurements including frequency error, EVM (composite EVM, data EVM, RS EVM), Reference Signal Tx Power (RSTP), OFDM Symbol Transmit Power (OSTP), time alignment between transmitter branches, DL RS power plus more

- Support for E-UTRA Test Models (E-TMs) for transmit signal quality measurements as well as RF power measurements as defined in 3GPP TS 36.141 V8.2.0 (2009-03)

- One button RF power measurements with pass/fail per 3GPP TS 36.141 V8.2.0 and 3GPP TS 36.521-1 V8.1.0. Measurements including channel power, transmit ON/OFF power (for TDD), ACP, spectrum emission mask (SEM), spurious emissions, occupied bandwidth and more

- Analysis of Tx diversity encoded signals

- Analysis of timing and phase offset for both Tx diversity and spatial multiplexing MIMO signals

- Auto detection of both uplink and downlink signals

- Flexible measurements let you view your signal in multiple ways: by resource block, sub-carrier, slot, or symbol—select all or a specific region for analysis

- Color coding by channel type highlights signal errors

- Add/delete users and edit parameters for each user for realistic testing

- Support for 3GPP-compliant equalization and EVM minimization

- The automatic resource block detection or manual user allocation using graphical resource allocation tool simplifies measurement setup

- Error and frame summary tables provide at-a-glance presentation of key measurement parameters

- Common tracking error, equalizer frequency, and impulse response let you view the channel from your signal’s perspective

Multiple access technology

Downlink and uplink transmission in LTE are based on the use of multiple access technologies: specifically, orthogonal frequency division multiple access (OFDMA) for the downlink, and single-carrier frequency division multiple access (SC-FDMA) for the uplink.

Transmission bandwidth

In order to address the international wireless market and regional spectrum regulations, LTE includes varying channel bandwidths selectable from 1.4 to 20 MHz, with sub-carrier spacing of 15 kHz.

In the case of multimedia broadcast multicast service (MBMS), a sub-carrier spacing of 7.5 kHz is also possible. Sub-carrier spacing is constant regardless of channel bandwidth. To allow for operation in different sized spectrum allocation, the transmission bandwidth is instead altered by varying the number of OFDM sub-carriers.

Frame structure

There are two radio frame structures for LTE: frame structure type 1 (FS1) for full duplex and half duplex FDD, and frame structure type 2 (FS2) for TDD. The frame structure for full duplex FDD.

This structure consists of ten 1 ms sub-frames, each composed of two 0.5 ms slots, for a total duration of 10 ms. The FS1 is the same in the uplink and downlink in terms of frame, sub-frame, and slot duration although the allocation of the physical signals and channels is quite different. Uplink and downlink transmissions are separated in the frequency domain.

FS2 is defined for TDD mode. Two switching point periodicities are supported—5 ms and 10 ms, each with an overall length of 10 ms and divided into 10 subframes. The 5 ms switch-point periodicity TDD frame structure.

For the 5 ms switch-point periodicity case, subframe 6 is a special subframe identical to subframe 1. For the 10 ms switch-point periodicity, subframe 6 is a regular downlink subframe. Table 2 illustrates the possible UL/DL allocations which have been specified in the 3GPP standard for TDD mode.

As show in Figure 2, the special subframe consists of special fields - downlink pilot timeslot (DwPTS), guard period (GP) and uplink pilot timeslot (UpPTS). Their total length is 1 ms.

However, within the special subframe the length of each field may vary depending on co-existence requirement with legacy TDD systems and supported cell size. Table 3 provides the supported special configurations which are also specified in 3GPP.

Resource block

The smallest time-frequency unit used for transmission is called a resource element, defined as one symbol on one sub-carrier. A group of contiguous sub-carriers and symbols form a resource block (RB). Data is allocated to each user in terms of RBs. For a Type 1 frame structure using normal cyclic prefix (CP), an RB spans 12 consecutive sub-carriers at a sub-carrier spacing of 15 kHz, and seven consecutive symbols over a slot duration of 0.5 ms.