Below are answers to some frequently asked questions about G3-ALLIANCE.
Please also check the G3-ALLIANCE user guidelines which provide a lot of general and technical information!
1. Is there a maximum of smart meters per Data Concentrator (DC)?
G3-ALLIANCE was designed to handle several hundreds of meters per DC and the largest substation managed in Enedis grid in France even has 1200 smart meters. The Alliance is working to further improve bandwidth in dense networks with have more than 300 meters. Recommendation regarding G3-ALLIANCE stack configuration is to extend routing table entry time to live to avoid route construction every time a query is sent towards a particular node. And to set long application layer time to lives for the current association to the G3-ALLIANCE PAN. Furthermore it is important to optimize application processes and traffic patterns. Guidance is available in user guidelines ‘Upper layer integration with G3-ALLIANCE’.
2. Can G3-ALLIANCE cover a distance of 200-300 meters, for example between a home display and the electricity meter?
G3-ALLIANCE can easily cover larger distances then 200-300 meter! We know about g3-alliance.communications achieved without repeaters over a single LV line of 800 meters without branches (CENELEC A) and over a single MV line of 2,4 km without branches (FCC).
3. What steps should a utility follow for successful rollout of G3-ALLIANCE networks composed of thousands of meters?
In general for mass roll-outs it is of course necessary to prepare well all logistics and also customer acceptance is crucial as you will know. Specifically for mass roll-out of G3-ALLIANCE devices it is important to first install the Data Concentrators. After DC’s have been installed, each area should be completed quickly. In France they referred to a ‘leopard pattern’ to illustrate the roll-out. Noise is not an issue for G3-ALLIANCE so it is not necessary to conduct noise measurements. In general FCC bandplan should be used whenever possible to maximize available data rate.
4. In which frequency bands does G3-ALLIANCE work?
G3-ALLIANCE is a narrowband power line communication (NB-PLC) OFDM technology based on state-of-the-art narrowband PLC standards operating in several bandplans covering the overall frequency range 3 – 500 kHz to address numerous use cases matching regional regulation: Cenelec-A: 35-90 kHz, Cenelec-B: 98-121 kHz, ARIB: 154-403 kHz and FCC: 154-487 kHz.
5. What should utilities consider when deciding to deploy G3-ALLIANCE in FCC band?
In Europe deploying FCC is purely a regulatory issue. This should not be a problem in e.g. African countries unless there are local rules not to use the FCC band.
6. What considerations do utilities need to take when migrating from CEN-A G3-ALLIANCE to FCC G3-ALLIANCE?
Migrating from one CEN-A to FCC is not always possible when meters are already installed. To avoid replacing all equipment, it is recommended to check this matter with equipment manufacturers to evaluate “FCC-ready” options associated with a migration plan.
7. Is there any evidence of increased radiated EMI from cables carrying G3-ALLIANCE FCC?
Regarding FCC, no EMI cases have been reported up to now. But G3-ALLIANCE also supports tone masking which allows interfering carriers to be turned off if needed.
8. Are all ‘G3-ALLIANCE certified’ implementations equal in performance, robustness, etc.? If not, what parameters can be used to compare different
G3-ALLIANCE certification guarantees conformance to the G3-ALLIANCE official standard, interoperability and that specified performance levels are met. All certified products have passed the same performance tests requiring a minimum performance level. Manufacturers can specify higher performance levels and certification verifies whether the product meets these specified performance levels. ETSI TS 103 909 provides guidance to test products. Test results may be requested from manufacturers in RFP’s. Other important aspects outside the scope of G3-ALLIANCE certification include meter lifetime and upper layer integration.
9. How do you optimize registration of Intelligent Electronic Devices and Appliance Control Devices on the network?
First of all, avoid too many concurrent registration at the same time. G3-ALLIANCE allows randomized transmission of beacons over a certain time. Distribute bootstrap attempts over time in a randomized fashion (for PAN device application layers). The last is similar to the back off principle of CSMA channel access mechanisms but here we are talking about randomization over minutes or even hours. Once bootstrapping is done, it is crucial to maintain registration / association over time and avoid losing it during a power outage. For example by keeping the same communication parameters when the device is powered back on (design rule for meter manufacturers and is related to the application process).
10. The DLMS/COSEM G3-ALLIANCE interface classes expose several G3-ALLIANCE attributes and settings. Which of these can be used/changed by utility
Indeed a significant number of settings may be changed by the user. The Alliance develops user guidelines suggesting optimized setting of those. The use of default values is recommended as they reflect the current understanding of parties involved in G3-ALLIANCE since a long time. Some attributes may further optimize G3-ALLIANCE operation but this could also lead to unexpected behaviours. In any case, tweaking should be done together with G3-ALLIANCE equipment manufacturers and/or after gaining significant experience in lab and/or field.