Microwave Engineering Europe - January/February 2009 - (Page 16)

16 TEST & MEASUREMENT — FEMTOCELLS Figure 2: The Agilent Technologies E4438C ESG. repeatable test environment for evaluating the receivers used in femtocells. Agilent Technologies offers a comprehensive suite of femtocell design and test equipment that spans the entire lifecycle – from R&D through manufacturing to network deployment and service assurance. The company also offers the industry’s ﬁrst 3GPP LTE femtocell reference design test solution, which provides RF and baseband engineers with a full-featured signal analysis solution for physical layer testing and troubleshooting. Further information Agilent Technologies will display its range of mobile communications design and test solutions at the Mobile World Congress in Barcelona, 16 – 19 February 2009. For more information on Agilent’s femtocell solutions go to www.agilent. com/ﬁnd/femtocell. Author biographies John Kikuchi is an application expert in the Signal Sources Division of Agilent Technologies. He has held various positions within Hewlett Packard/Agilent in his 25 years experience with the company. John is a graduate of UC Berkeley with prior experience in the US Air Force before to coming to Agilent. Frank Palmer is a wireless marketing program manager for Agilent Technologies. Prior to this job, he held positions as a wireless industry marketing manager and wireless applications engineer where he was responsible for understanding the test needs of the wireless communications industry. Frank received his B.S. degree in Electronic Engineering from California Polytechnic State University, San Luis Obispo. one and eight and the automation of signal generation through SCPI commands. Five measurements in particular, are especially helpful in verifying GPS receiver performance. These are: 1) Time To First Fix (TTFF): The time interval between the GPS receiver startup (power up) and the ﬁrst-valid navigation 3D-data point, derived from the simulation. GPS receiver TTFF measurements may include cold, warm and hot start conﬁgurations. 2) Receiver Sensitivity: A measure of the signal strength (C/No) under various GPS-signal power levels, as well as the power level and C/No ratio level at which the 3D location ﬁx is lost. 3) Static Navigation Accuracy: The accuracy of the GPS receiver location ﬁx with respect to the simulated location. 4) Reacquisition Time: The time required to reacquire a navigation ﬁx following a short blockage of all GPS signals during normal operation. 5) Radio-Frequency Interference: The GPS receiver’s ability to operate in the presence of interfering (jamming) signals that may be received through its input. Note that a second RF source is required to provide the RF interference signal. Testing assisted GPS Assisted GPS (A-GPS) uses the cellular communications channels to improve the accuracy, TTFF and reliability of the GPS receiver. Technologies such as A-GPS are breaking down the barriers to using GPS in femtocells. However, since it uses the existing cellular network in its implementation its adoption demands an effective functional AGPS receiver test to assure service providers that A-GPS operation will not interfere with cellular phone calls. Instruments such as the Agilent Technologies E4438C ESG signal generator with GPS personality can be used, together with Agilent’s 8960 wireless communications test set, to perform the types of functional testing needed to meet service provider requirements. Figure 3 shows the connections required to set up the mobile device A-GPS functional test system. Both the 8960 and E4438C are connected to the PC controller via GPIB. The DUT is coupled to the instruments via antennas connected at the RF ports of each of the 8960 and E4438C. Conclusion The deployment of femtocells into the residential and small business environments is set to grow signiﬁcantly. A variety of technologies will be used within the femtocell and this will require a range of design and test tools that can be used by engineers as they take on the task of creating products that meet the service providers’ and end users’ needs. GPS will take a prominent role in femtocell systems in order to provide accurate location and timing information. Veriﬁcation of the GPS or A-GPS receiver’s performance is therefore critical. The ability to simulate GPS signals easily with a high-performance RF source provides greater ﬂexibility in creating an accurate and Figure 3: Testing A-GPS. Microwave Engineering Europe ● January/February 2009 ● www.mwee.com http://www.agilent.com/find/femtocell http://www.agilent.com/find/femtocell http://www.mwee.com

Table of Contents Feed for the Digital Edition of Microwave Engineering Europe - January/February 2009

Microwave Engineering Europe - January 2009 News Contents Comment Using KPIs to Ensure Quality in a Converging Network Amplifier Error Vector Magnitude Characterisation Using High-Speed Modular PXI Instruments GPS: Making a Play for Femtocells Accelerating Global WiMAX Adoption: The Move to Picocell and Femtocell Base Stations Addressing PA Efficiency for Multi-Mode Wideband Handset Applications Wi-Fi: Mobile Feature or Fundamental RAN? Products Calendar

Microwave Engineering Europe - January/February 2009

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.