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Agilent
LTE Reference Vector
White Paper
Introduction
The third-generation Universal Mobile Wireless developers are under The breadth and flexibility of these
Telecommunications System (UMTS), increasingly demanding schedules new emerging wireless standards
based on Wideband Code-Division to develop products before wireless such as LTE and Mobile WiMAX pres-
Multiple Access (W-CDMA), has been standards finalize to meet product ent significant challenges for FPGA
deployed all over the world. To ensure shipment schedules. This introduces design. For example, LTE supports a
that this system remains competitive product development risks to the number of modulation types (QPSK,
in the future, the 3rd Generation baseband coding/decoding physical- 16QAM, 64QAM) with many different
Partnership Project (3GPP) began layer design. configurations in the transport block
a project in November 2004 to size, Resource Block (RB) alloca-
define the long-term evolution of The physical-layer baseband design tion, different CRC lengths/types,
UMTS cellular technology. The cycle often progresses in parallel etc. Traditional FPGA development
specifications related to this effort with a wireless standard which is methodologies of writing/creating
are formally known as the Evolved still rapidly evolving. Thus, algorithm independent test vector references
UMTS Terrestrial Radio Access (E- definition is subject to the developer's (in addition to writing the actual HDL
UTRA) and Evolved UMTS Terrestrial interpretation of the preliminary stan- code needed for the implementation)
Radio Access Network (E-EUTRAN) dard, which may not yet be complete may become problematic in terms of
but are more commonly referred to and may not yet be well-defined. the development overhead needed to
by the project name LTE. The first Unfortunately, misinterpreting the generate the many test vectors sets
version of LTE is documented in wireless standard on the baseband required to verify the many configura-
Release 8 of the 3GPP specifications. implementation can result in costly tions supported by LTE and Mobile
time delays in re-working designs and WiMAX.
potentially missing critical time-to-
Rapid evolution of new commercial market windows. A new approach is needed to
wireless standards such as 3GPP facilitate rapid development and
Long Term Evolution (LTE) poses Designing flexibility into hardware- testing of FPGA-based physical-layer
significant challenges for physical software platforms is key to SDR coding/decoding implementations for
layer baseband design of commercial development, where a common emerging standards such as LTE. This
wireless products. This also creates radio platform may need to be re- white paper outlines an improved
challenges for Software-Defined configurable to support multiple approach to verify FPGA development
Radio (SDR) development, in which a signal formats (LTE, WiMAX, WCDMA, using independent and configurable
common hardware/software platform custom/proprietary formats, etc.). reference test vectors.
may be required to support multiple The flexibility of FPGAs for the cod-
wireless standards such as LTE and ing/decoding chain is attractive for
Mobile WiMAXTM. these applications.
FPGA Development--Today's Existing Approach
FPGA developers typically start with To summarize, today's approach
system specifications that include to FPGA development highlights
behavioral requirements. These several key challenges:
specifications will likely have some
level of mathematical or pseudo-code