Wireless operation
PTP 450 Configuration and User
pmp-0815 (August 2015)
1-21
Matrix B: This technique provides for the ability to double the throughput of a radio
transmission under proper RF conditions. Different data streams are transmitted
simultaneously on two different antennas.
Cyclic Prefix
OFDM technology uses a cyclic prefix, where a portion of the end of a symbol (slot) is
repeated at the beginning of the symbol (slot) to allow multi-pathing to settle before
receiving the desired data. A 1/16 cyclic prefix means that for every 16 bits of throughput
data transmitted, an additional bit is used.
Frame Period
The time between the beginning of a frame and the end of that frame. This can be either
2.5 ms or 5.0 ms.
Encryption
The Cambium PTP 450 Series supports optional encryption for data transmitted over the
wireless link. The PTP 450 Series supports the following forms of encryption for security of
the wireless link:
DES (Data Encryption Standard)
: An over-the-air link encryption option that uses
secret 56-bit keys and 8 parity bits. DES performs a series of bit permutations,
substitutions, and recombination operations on blocks of data. DES encryption does
not affect the performance or throughput of the system.
AES (Advanced Encryption Standard):
An over-the-air link encryption option that
uses the Rijndael algorithm and 128-bit keys to establish a higher level of security than
DES. AES products are certified as compliant with the Federal Information Processing
Standards (FIPS 197) in the U.S.A.
Further reading on wireless operation
For information on planning wireless operation, see
. This
section describes the regulatory restrictions that affect radio spectrum usage, such as
frequency range.
