Last year, I outlined several challenges facing enterprise private wireless networks (here). In this post, I wanted to highlight the role of dual SIM phones and eSIM technology in enabling private wireless networks. The SIM impacts how subscribers access the private network and, consequently, the quality of experience which makes the SIM a critical part of enterprise networks. The approach to SIM that a private network operator takes has to match the deployment scenario and business objectives.
The mechanics of accessing private networks
There are different ways for a subscriber to access a private network. For instance, a subscriber can roam onto a private network. This requires roaming agreement between the private network operator and mobile network operators. Alternatively, a subscriber could use a phone that supports dual SIM cards. In this case, the subscriber could choose and prioritize over which network to receive voice and data services.
Roaming and its challenges
Roaming works best when the public network and private networks are isolated from each other. This could be, for instance, a remote oil field, an underground mine, or a ship at sea. In such a case, the phone could select the appropriate roaming network without difficulty – just as it happens when someone travels. The problem with roaming happens when the public and private network coverage overlaps. It is an optimization nightmare to force the phone onto one network versus another. Anyone who worked on wireless network optimization would attest to this.
From a practical perspective, negotiating a roaming agreement with a mobile network operator could be an arduous process for an enterprise. Not all markets are hospitable to roaming or an MVNO models – such as the case in Canada. In some parts of the world, the enterprise may see to be as independent of the public network as possible. This would be possible with a dual SIM phone.
The advantage of dual SIMs
More and more phones feature dual SIM slots. More recently, eSIM is commonly used for one of the modules. Apple for instance began supporting dual SIMs with some models of the iPhone X. The recent iPhone 13, just as the iPhone 12, features dual SIMs – one physical and one eSIM. This feature is not well advertised because network operators are not favorable to it. Outside North America, dual SIM phones have been abundantly available and popular for a long time.
With two SIM cards, users can receive service when present in the coverage area of a private network without the headaches associated with roaming where the public and private network coverage overlaps. This could be on a university campus for instance, or a venue such as a stadium or a convention center. Dual SIM Dual Standby (DSDS) phones allow the user to configure and prioritize the data and voice services over both public and private networks.
eSIM technology lowers the barriers and inconvenience of accessing private networks as it allows provisioning and configuration on demand which could be, for instance, with a QR code. It is a real game-changer in the history of private wireless networks!
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Concluding thoughts
In 1989, my alma mater, Case Western Reserve University, deployed the first and most comprehensive fiber optical network on any US university campus. CWRUnet, as it was called, made available 10 Mbps connections to thousands of locations on campus. In these pre-Wi-Fi days, it was a considerable achievement. Later, the project expanded to provide fiber connectivity to locations around the university.
I mention this because educational institutions could be pioneers in deploying private wireless networks. In fact, we saw US government funding stimulate the interest of schools and universities in CBRS. In the CBRS auction, three educational institutions won a combined 15 licenses. That’s too little, but understandable and even justifiable. But 80 MHz of unlicensed CBRS GAA spectrum is available for anyone to tap into. Could educational institutions be the leaders in private wireless network adoption – contrary to many analysts expectations? The opportunities that such networks provide are huge; and perhaps so would the impact be on the incumbent operators.
