User's Manual

15
DragonWave Inc. Features
3Features
3.1 Main Features
Lite embraces the following features:
• Adaptive Coding and Modulation (ACM)
• Transmit Power Control (TPC)
• 2x2 Multiple-input and Multiple-output (2x2 MIMO)
• Dynamic Frequency Selection (DFS)
• Dynamic Channel Selection (DCS)
• Retransmission
• Configurable Uplink/Downlink Ratio
• Quality of Service (QoS)
• Power over Ethernet
• Synchronization
• Co-site Synchronization
• OFDM Modulation
• Low-density Parity Check (LDPC) Encoding
• LLDP
• Radio Port Performance Monitoring
• Adaptive Noise Immunity (ANI)
3.2 Adaptive Coding and Modulation (ACM)
ACM allows the user to improve link utilization by making high capacity data transmis-
sion reliable. ACM changes code and modulation according to the link quality in the
same channel bandwidth.
Figure 5 ACM for Traffic Growing
ACM refers to the automatic modulation adjustment that a wireless system can perform
to prevent weather related fading from disrupting communication on the link.
When server weather condition, such as a heavy rain, affects the transmission and
reception of data over a wireless network, the radio system automatically changes the
modulation, so that non-real-time data-based applications may be affected by signal
degradation, but real-time applications will run smoothly and continuously.
Since communication signals are modulated, higher modulation levels increase the
number of bits that are transferred per signal, thus enabling higher throughputs, or better
spectral efficiencies. It should be noted that, when using a higher modulation technique,
better signal-to-noise ratios (SNR) are needed to overcome interference and maintain a
tolerable bit error ratio (BER) level.