Cambium Networks cnWave, User Manual

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Product Description 29
Time-division duplexing access mechanism
60 GHz cnWave uses a Time Division Duplex (TDD) channel access mechanism. All cnWave nodes are
time-synchronized and this is achieved through internal GPS, IEEE 1588(roadmap), or Cambium Sync
(roadmap), and each sector of a node is assigned specific times during which it can transmit or receive. A
timing pulse that resets the Timing Synchronization Function (TSF) on the DN is repeated once every
second (1PPS). This timing pulse occurs exactly at the turn of each second and Sub-Frames begins every
200 microseconds.
General operation of MAC layer
MAC is highly modified from that in IEEE 802.11-2016. Use TDD MAC by substituting TDD access for all
other access. 60 GHz cnWave supports a fixed 50-50 up/down ratio.
60 GHz cnWave uses only the following frames:
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Data
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QoS-Null (frame does not carry any data)
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Management Action (for example, beam-forming, and others.)
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Block ACK (used for sending an ACK to multiple nodes/packets at once)
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ACK
Frame types
Below are the types of frames in 60 GHz cnWave:
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Management frames - A node sends all management frames using the DMG control mode PHY,
MCS 0.
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Control frames - A node sends the ACK frame using the DMG control mode PHY, MCS 0. A node
sends the Block ACK frame using the DMG single carrier PHY, MCS 1.
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Data frames - A node sends data frames using MCS 2 through MCS 12 of the DMG single carrier
PHY, as determined by the link adaptation algorithm.
Wireless encryption
The 60 GHz cnWave supports optional encryption for data transmitted over the wireless link using a
choice of three different encryption algorithms:
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TLS RSA: The Outdoor Units (ODUs) exchange RSA certificates to authorize the remote unit and
agree on a randomly-generated master secret. The TLS RSA option supports the unencrypted
operation of the wireless link, or encryption with 128-bit AES.
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TLS PSK 128-bit: Both ends of the link are configured with the same 128-bit pre-shared key as a
master secret. The wireless link is encrypted using 128-bit AES.
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Advanced Encryption Standard (AES): A symmetric encryption algorithm that is approved by U.S
Government organizations (and others) to protect sensitive information. The AES implementation
in 60 GHz cnWave is approved to FIPS 197.