Stephen Patrick, Author at Microwave Link

1024QAM Microwave Links

1024QAM Microwave Links for High Capacity Wireless Transmission

High Capacity Microwave Links from leading vendors use 1024QAM modulation to achieve high capacity, spectral density and efficiency without sacrificing reliability. This technology sets a new benchmark for microwave transmission capacity for operators including 4G / LTE Backhaul links for mobile operators as well as last-mile links, backbone and other applications.

High Capacity Links require High Order QAM modulation

Leading long-haul microwave equipment vendors are now using dependable long-distance transmissions using 1024 QAM. Relative to the industry-standard 256 QAM, this represents a 25% increase in capacity (and up to double the capacity of legacy SDH links), with all other factors the same. Compared to older 4QAM modulation the increase to 1024QAM is five-fold. 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

CableFree 1024QAM modulation tradeoffs 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 use of ACM 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.

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.

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 More Information on High Capacity Microwave Solutions, Please Contact Us

Microwave Antenna Alignment

Alignment of Microwave Antennas for Digital Microwave Transmission Systems

This article contains generic instructions for alignment of Microwave antennas. Specific products may have different features, in which case please refer to the documentation provided for those products:

Antenna Alignment for Microwave Links

This guide explains how to achieve the optimal antenna alignment of microwave antennas when used with modern digital microwave products. Before attempting to do the alignment it is highly recommended that you read this guide in detail. For specific commands please consult the manual of the product being installed

Step 1: Preparation:

Mount the antenna on the tower according to the antenna installation instructions: Ensure that the adjustment bolts move smoothly and the range of motion is sufficient for the expected angle of up and down (elevation) tilt. Ensure that the mount itself is attached securely and all safety precautions have been taken.

CableFree Microwave Antenna Alignment using DVM

Step 2: Coarse Alignment:

Visually align the antenna with the far end. The most common ways to do this are :

1) If the visibility is good and the sun is in the correct position, have someone at the far end location reflect the sun with a mirror so the location is obvious.

2) If visibility is poor, use GPS coordinates and a GPS compass to aim the antenna coarsely.

CableFree Microwave Antenna Alignment avoiding Sidelobes

Step 3: Fine Alignment.

Before conducting fine alignment, the ODUs at both ends of the link must be attached properly to the antenna via the direct mount or remote mount (using Waveguide) and the far end ODU must be powered on and transmitting. The ODU lightning surge suppressors and grounding provisions should be put in place as well before alignment. The local ODU must be powered on, but need not be transmitting.

Ensure that:

1) Frequency of the far end transmitter matches the frequency of the local receiver.

2) The TX output power is not set above the level of the license.

3) ATPC is turned OFF on the far end.

4) Alignment mode is ON for SP ODUs – Display on ODU and IDU will update at 5 times per second.

FINE ALIGNMENT PROCEDURE

1) Adjust the azimuth over a 30 degree sweep by turning the adjustment bolt in increments of 1/10^th turn to avoid missing the main lobe. When the highest signal has been found for azimuth, repeat for the elevation adjustment.

2) Turn the local transmitter on to allow alignment at the far end.

3) Move to the far end of the link and repeat step 1.

4) Lock down the antenna so no further movement can occur.

5) Install the antenna side struts supplied with the antenna.

6) Verify the RSSI remains the same and is within 2-4 dB of the expected levels.

7) Check the ODU connector seals.

8) Turn alignment mode OFF

9) The alignment is complete.

Microwave Mobile Backhaul

Packet Microwave Radios for Mobile Backhaul

To deliver a compelling quality of experience for subscribers, you must respond quickly to growing traffic demands. Modern Packet Microwave Mobile Backhaul products help you maximize the network’s performance by enabling rapid deployment of scalable backhaul to cell sites. Modern solutions include a portfolio of microwave products to address the backhaul needs of 2G, 3G, and LTE macro cells and 3G, LTE, and Wi-Fi® small cells. Radio spectrum is maximized using innovative techniques to maximize payload capacity to support the evolution to LTE and heterogeneous networks. Unique, common radio support for indoor and outdoor deployments enhances savings potential.

Packet Microwave Mobile Backhaul is a key component in a modern end-to-end mobile backhaul solution, which provides the flexibility, scale and operational simplicity to lower the total cost of ownership and simultaneously enhance the mobile service experience.

BENEFITS

Economic benefits

Rapidly support the optimal cell site location

Complete backhaul portfolio for macro cells and small cells
Support for all sites including both end and intermediate cell sites
Space and power efficiency
Full outdoor option to meet different microwave site space requirements

Achieve maximum spectral performance

Maximum bandwidth per band
Intelligent compression
Advanced quality of service levels supporting subscriber quality of experience

Scale the network cost effectively

Reliably bond radio channels to create larger microwave links
Any topology, any number of microwave link directions
Network awareness for both Carrier Ethernet and/or IP/MPLS networks

Be operationally efficient

Common radio for all cell sites
Evolutionary path from hybrid microwave to packet microwave at the touch of a button
Management beyond basic IP partner integration

Deployment, management, end-user benefits

Grow and retain subscribers by maximizing the mobile experience

Infrastructure support for increased subscriber bandwidth demands
Ability to react quickly to subscriber demand with optimally-located cell sites
Increased capacity that supports high bandwidth data applications

COMPONENTS

Packet Microwave Mobile Backhaul integrates a modern microwave portfolio with small cell optimized products to provide a complete backhaul offering for small cells and/or macro cells.

Read on in our following pages to find out more about technologies used in mobile backhaul applications

Key technologies in a modern Microwave Network

Key technologies used in modern Microwave Networks – what to look out for:

Build faster, more efficient microwave networks

Critical features of a modern microwave network product range let you deliver more data with superior performance while using less spectrum and equipment. These features include:

Complete range of low cost to high end modular solutions
Efficient Modulation schemes of up to 256QAM, 512QAM, 1024QAM, 2048QAM and 4096QAM
Automatic Transmit Power Control (ATPC)
Advanced packet compression techniques that increase channel capacity by up to 300%
Scalable multichannel microwave links that support increased capacity and reliability
Adaptive Coding and Modulation (ACM) that extends across multiple channels to sustain maximum performance in all environments
Software Defined Radio (SDR) Microwave Technology

Boost capacity and reliability with advanced networking

With a modern microwave network, you should expect advanced Carrier Ethernet networking capabilities that can double network capacity while delivering high availability. These capabilities include:

Unique ring and mesh topology configurations that can double network capacity, improve reliability and reduce network costs
Integrated IP-microwave solutions that reduce space and power consumption
The ability to support TDM, Ethernet and IP services on a single packet-based network

Simplify operations with an end-to-end approach

Expect to see: a complete family of microwave solutions that addresses all network sizes and locations including tail, hub and backbone. With an approach that uses common equipment and software across all sites, vendors should help you streamline management processes and reduce TCO. Features offered:

Common radio transceivers that reduce the need for spares across all applications
A flexible range of Indoor Units (IDUs) and Outdoor Units (ODUs) to reduce space and power consumption
Common software and network management that simplify operations across the network