EVM (Error Vector Magnitude) is used as the metric for transmitter signal quality compliance in many modern communication systems. Examples include IS-54/IS-136, GSM/EDGE 3GPP-WCDMA, and 802.11a wireless LAN commercial standards.
MUOS (Mobile User Objective System) [1][2] is an example of a next generation military communications system leveraging the commercial use of this metric. In this paper, EVM simulation and engineering analysis techniques are described. All major aspects of a generic transmitter physical layer system are simulated, including the impact of distortions due to modulator imbalances, phase noise, non-linear amplifiers, spurs, and non-ideal filtering. Specific data values for individual distortions are taken from the TDRSS [3] and WGC [4] transmitter systems, published in open literature.
Matlab simulation results are compared to analytical predictions [5] for the generic transmitter system, validating the technical approach. The resulting transmitter signal distortion is translated from EVM to Ec/No degradation for determination of end-to-end link performance. Practical issues on EVM laboratory measurements and the diagnostic value of EVM are also addressed.
A. Wang has been working as system engineer for the Lockheed Martin (Sunnyvale, California) MUOS satellite communications program since 2002. She has previously worked for Applied Signal Technology and ATK Mission Research Corporation developing adaptive signal processing algorithms for communications applications. She received the B.S.E.E. degree from the University of New Orleans, and the M.S.E.E. and Ph.D.E.E. degrees from the University of California at Berkeley.
Mr Ligmanowski has held the roles of Signal Analyst, Signal Analysis Manager and Communication Systems Engineer for Lockheed Martin. He received a BSEE in 1975 and MSEE in 2001 from Drexel University. From 1975 to 1986 he was a hardware engineer at the Naval Air Test Center, Naval Surface Weapons Center and Naval Research Laboratory. Recent experience includes analysis work on Bandwidth Efficient Modulation. Mr Ligmanowski contributed to the MUOS proposal and development effort in the areas of 3G wireless technology, system capacity and Ka-band feederlink design. Presently he leads the Ground Communications Subsystem for the GOES-R program at Lockheed.
J. Castro (no information available)
A. Mazzara (no information available)