Agilent Measurement Journal - Issue 5 - 2008 - (Page 21)

Conﬁguring bandwidth LTE is being designed to support the international mobilewireless market, regional spectrum regulations and spectrum availability. To accomplish this, variable channel bandwidths from 1.4 MHz to 20 MHz are speciﬁed. Standard subcarrier spacing is 15 kHz but subcarrier spacing of 7.5 kHz is also possible for the new LTE evolved multimedia broadcast multicast system (eMBMS), which is to be speciﬁed in Release 9 of the 3GPP speciﬁcations. Subcarrier spacing is independent of the channel bandwidth. The smallest amount of allocated resource in both the downlink and uplink is called a resource block (RB). An RB is 180 kHz wide and lasts for 0.5 ms. For standard LTE, an RB consists of 12 subcarriers at a 15-kHz spacing, while for eMBMS using the optional 7.5-kHz spacing, the RB is 24 subcarriers wide. The maximum number of RBs supported by each channel bandwidth is given in Table 4. Table 4. Channel bandwidth conﬁgurations Frame structure Two radio-frame structures are speciﬁed for the LTE downlink: frame structure type 1 (FS1) for full-duplex and half-duplex FDD, and frame structure type 2 (FS2) for TDD. These frame structures are shown in Figures 5 and 6. FS1 is optimized to co-exist with existing FDD UMTS systems and consists of ten 1 ms sub-frames, each composed of two 0.5 ms slots for a total duration of 10 ms. FS1 is the same in the uplink and downlink in terms of frame, sub-frame and slot duration, although the composition of the physical signals and channels is different. Uplink and downlink transmissions use different spectra. One radio frame, Tf = 307200 Ts = 10 ms One slot, Tslot = 15360 Ts = 0.5 ms #0 #1 #2 #3 #18 #19 One sub-frame Channel bandwidth (MHz) Nominal transmission bandwidth conﬁguration (MHz) Nominal transmission bandwidth conﬁguration (resource blocks) 1.4 3.0 1.08 2.7 5 10 15 20 4.5 9 13.5 18 Figure 5. Frame structure type 1 (TS 36.211 Figure 4.1-1)3 6 15 25 50 75 100 The structure of FS2 is a lot more ﬂexible than FS1. An example of an FS2 structure is shown in Figure 6. This example is for a 5 ms switch-point periodicity and consists of two 5 ms halfframes for a total duration of 10 ms. Subframes consist of either an uplink or downlink transmission, or a special subframe One radio frame, Tf = 307200 Ts = 10 ms One half frame, 153600 Ts = 5 ms One slot, Tslot = 15360 Ts 30720 Ts Subframe #0 Subframe #2 Subframe #3 Subframe #4 Subframe #5 Subframe #6 Subframe #8 Subframe #9 One subframe, DwPTS GP UpPTS 30720 Ts Figure 6. Frame structure type 2 (for 5 ms switch-point periodicity), TS 36.211 Figure 4-2.13 DwPTS GP UpPTS Agilent Measurement Journal 21

Table of Contents Feed for the Digital Edition of Agilent Measurement Journal - Issue 5 - 2008

Agilent Measurement Journal Issue 5 Finding a New Path when Assumptions Break Down Contents Testing MIPI D-PHY Protocols Oscilloscope Firmware Update DNA Replication Joining the LTE/SAE Trial Initiative Testing Proteins Praise for DC Power Analyzer Scripting Features for AMDS Testing Hybrid PCBA Systems Improving the Gene Expression System Workflow Turning a “Good Enough” Test Strategy into One That’s Reliable, Repeatable and Traceable Understanding the Effects of Limited-Bandwidth Channels on Digital Data Signals Introducing the 3GPP LTE Downlink Validating the 26 Validating the Physical and Protocol Layers in DDR Memory Interfaces Understanding Total Jitter Measurements of Low Probabilities Using Behavioral-Model Simulation to Accurately Predict First-Order PLL Performance Creating Synchronous High-Frequency Sampling across Multiple Digitizers Overcoming the Challenges of Testing FlexRay Networks Understanding Operating Life and Repeatability of Electromechanical Switches and their Effect on Total Cost of Ownership Implementing Micro and Nano LC/MS Techniques for High Sensitivity Lipidomics Analysis

Agilent Measurement Journal - Issue 5 - 2008

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