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7.3.3.2 Bit Error Rate (BER)
Table 7-7 provides Prec equations that will result in a customer achieving a BER of 10 -5
for TDRSS compatible signals. The IF service BER depends on the customer receiver
characteristics. Refer to paragraph 7.3.6 for more information on the IF service. The
BER Prec equations are applicable for non-powered flight dynamics and the following
conditions:
a. Data encoding. Customer platform transmission of Rate 1/2 convolutional
encoded or uncoded signals are supported for KuSA return services. Detailed
rate 1/2 coding design is described in Appendix B. Reed-Solomon decoding is
available to WDISC customers; typical performance is given in Appendix K.
b. Received Power. Prec is in units of dBW. The customer project, in determining
its design requirements for minimum customer platform EIRP, must take into
account customer platform transmit antenna pointing losses, the space loss
between the customer platform and the TDRS, and the polarization loss
incurred between the customer platform transmit antenna and the TDRS
receive antenna. The maximum TDRS receive antenna axial ratio is given in
Table 7-7 (also refer to Appendix A). For DG1 and DG2 services, the following
conditions apply:
1. Balanced Power Single Data Source-Identical Data on the I and Q
Channels (DG1 mode 1 and 2 only). For a customer platform
synchronously transmitting identical data on the I and Q channels (single
data source-identical data) with a balanced I and Q channel power
division, the total (I+Q) Prec must be consistent with the minimum Prec for a
10 -5 BER listed in Table 7-7, where dr is the single data source data rate.
Refer to Appendix B for further information on this data configuration.
2. Balanced Power Single Data Source-Alternate I/Q Bits (DG2). For a
customer platform transmitting alternate I and Q data bits from a data
source (single data source-alternate I/Q bits), the total (I+Q) Prec must be
consistent with the minimum Prec for a 10 -5 BER listed in Table 7-7, where
dr is the single data source data rate prior to separation into the I and Q
channels. The Q/I (power) must be equal to 1:1. Refer to Appendix B for
further information on this data configuration.
3. Balanced Power Single Data Source-Alternate I/Q Encoded Symbols
(DG2 only). For a customer platform transmitting alternate I and Q
encoded symbols from a data source (single data source-alternate I/Q
encoded symbols), the total (I+Q) Prec must be consistent with the
minimum Prec for a 10 -5 BER listed in Table 7-7, where dr is the single data
source data rate prior to the rate 1/2 encoder. The Q/I (power) must be
equal to 1:1. Refer to Appendix B for further information on this data
configuration.
4. Unbalanced Power Single Data Source-Identical Data on the I and Q
Channels (DG1 mode 1 and 2). For a customer platform synchronously
transmitting identical data on the I and Q channels (single data source-
Revision 10 7-30 450-SNUG