CableFree 1024QAM Microwave Links for High Capacity Wireless Transmission
High Capacity Microwave Links from leading vendors such as CableFree: Wireless Excellence use 1024QAM modulation to achieve high capacity, spectral density and efficiency without sacrificing reliability. This new technology sets a benchmark for microwave transmission capacity to power modern networks including 4G/LTE Backhaul, Last-Mile Links, ISP Backbones, Corporate LAN Extensions and Wireless Metropolitan Area Networks (Wi-MAN), all of which are under continual pressure for bandwidth upgrades and capacity improvements from user traffic.
High Capacity Links require High Order QAM modulation
Leading long-haul microwave equipment vendors such as CableFree are now using dependable long-distance transmissions using 1024 QAM. Compared to older 4QAM modulation the new 1024QAM gives a five-fold (5x) increase in capacity. Relative to competing industry-standard 256 QAM products, this represents a 25% increase in capacity (and up to double the capacity of legacy 128QAM SDH links), with all other factors the same. Operators of long-haul microwave links will certainly enjoy the boost to their capacity with 1024 QAM, especially when these upgrades are relatively painless and generally require only a minor and quick swap of equipment.
Adaptive Coding and Modulation (ACM)
Leading microwave equipment vendors are able to keep their long-haul transmission links operational even in transient fade and noisy conditions. The enabling technology is ACM: Adaptive Coding and Modulation. Microwave links with ACM technology automatically sense the quality of the transmission link and can automatically decrease the modulation technique in case of degraded signal quality due to interference or other microwave propagation problems such as weather. So, if a microwave transmission is operating at maximum capacity using 1024QAM and suddenly encounters interference or high rainfall, a system such as the CableFree microwave system automatically steps down the modulation to lower levels until the transmission network, although at lower capacity now, maintains the ultra high level of link reliability and availability. As the temporary weather effects disappear, the microwave system automatically re-applies more efficient higher-order modulation techniques to regain full capacity.
Overcoming Tradeoffs due to High Order QAM Modulation
With increasing modulation the receiver sensitivity is greatly reduced, and generally transmit power has to be reduced due to linearity constraints in the transmitter. For fixed modulation speeds the result is either increase of antenna size or reduced distances, which may prevent an operator upgrading to higher capacity. The answer to this is use of Adaptive Coding and Modulation (ACM) which allows use of 1024QAM whilst avoiding sacrifice of distance or antenna sizes, by graceful step-down of modulation to lower rates during rare periods of high rainfall. For an operator the combination of 1024QAM and ACM give the best possible outcome: higher capacity without need for larger antennas, whilst retaining excellent system availability and reliability including in heavy fade/rainfall.
Increase of modulation beyond 1024QAM
Some vendors are promoting microwave products with 2048QAM and 4096QAM. These headline QAM number appear impressive but the small % capacity increase for each QAM step is matched by decreased receiver sensitivity of 3dB for each step hence greatly decreased range. For example from 1024QAM to 2048QAM there is a 10.83% increase in capacity, but a 3dB receiver penalty. Increasing to 4096QAM increases capacity by another 9.77% but another 3dB receiver penalty.
The main other strategy for increasing microwave link capacity includes XPIC which immediately doubles of capacity, but with a small coupling loss penalty which is tiny by comparison. Therefore we consider 1024QAM with XPIC to be an “optimum” for modern networks, and the range performance penalty for stepping beyond 1024QAM to be too severe to be worthwhile.
Use along with other bandwidth-enhancing technologies such as XPIC
1024QAM modulation is fully compatible with other methods to increase capacity such as XPIC (Cross Polar Interference Cancellation). An advanced microwave modem featuring 1024QAM and XPIC can greatly increase capacity. XPIC alone offers double the capacity compared to a single polarised non-XPIC solution.
CableFree Microwave Products offering 1024QAM
The following CableFree microwave links offer 1024QAM as standard for high capacity microwave networks:
CableFree FOR3 is a Full Outdoor Radio ideal for Zero-Footprint installations in busy urban installations where there is no indoor rack space or locations
- Full Outdoor Radio for Zero Footprint Installations
- Up to 1024QAM modulation
- Up to 112MHz channel width
- Up to 880Mbps (1+0) and 1.76Gbps (2+0) capacity
- Licensed 4 to 23GHz bands supported
- Unlicensed 5, 17, 24GHz supported
- ACM (Automatic Coding and Modulation)
- Power over Ethernet (PoE) supply
- Optional SFP Fibre Optic interface
- Carrier Ethernet features: SyncE and others
CableFree HCR is a Split-Mount radio with advanced features including 1024QAM dual modems and XPIC support as standard.
- 1024QAM modulation
- Dual Modems supported
- Up to 60MHz channel width
- Up to 470Mbps (1+0) and 940Mbps (2+0 XPIC) capacity
- XPIC Feature included as standard
- Licensed 4 to 42GHz bands supported
- ACM (Automatic Coding and Modulation)
- 3x GBE and 4x SFP for up to 7 Gigabit Ethernet interfaces
- Optional Expansion Modules for 16E1/T1 and ASI Broadcast Interfaces
- Carrier Ethernet features: SyncE, IEEE1588v2, VLAN, MSTP, LACP, Ethernet Path/Ring Protection, MEF9, MEF14
1024QAM Microwave Summary
These latest advancements in advanced microwave modulation offer network operators an easy and inexpensive upgrade path to higher capacities to meet demand. Advanced modulation technology of 1024QAM is fully shipping and available today and offers a very cost-effective way to boost capacity in long-haul microwave applications.
For Further Information
For further information on the range of CableFree wireless networking products:
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