This post discusses whether SIMs are becoming obsolete due to Wi-Fi, which is able to support both voice and Internet services on mobile and portable devices.
Both the neophyte and experienced mobile/cellular phone user alike tend to be familiar with the term “SIM” or “SIM card”. They might not know what it means, or how it functions, but it is widely considered an essential component for the proper functioning of a mobile/cellular phone. However, through current advances in technology it is indeed possible to operate mobile/cellular phones without a SIM. This post outlines the key functions of a SIM, but more importantly, highlights why it might be less critical to the mobile and other portable devices as we know it.
What is a SIM?
A SIM (Subscriber Identity Module or Subscriber Identification Module) or SIM card is an integrated circuit that stores information specific to a particular mobile/cellular network, and is used to identify and authenticate its subscribers. Critical information stored on SIMs include,
- an Integrated Circuit Card Identifier (ICCID)
- an International Mobile Subscriber Identifier (IMSI)
- an Authentication Key (Ki)
- a Local Area Identity (LAI) and
- an Operator-specific Emergency Number
Additionally, SIM cards can offer some storage of user-generated data and can encrypt phone transmissions to reduce unlawful interception.
Devices based on Global System for Mobile Communication (GSM) technologies typically require SIMs. These technologies tend to predominate in the Caribbean, and include standards such as EDGE (Enhanced Data Rates for GSM Evolution), HSPA (High Speed Packet Access) and Long Term Evolution (LTE). (See our post, EDGE, WiMAX, 3G, 4G: what’s the difference?, for more details on the different mobile technologies).
Conversely, there are mobile/cellular technologies that do not need SIM cards. Instead, authentication and security information is embedded into the device itself. However the growing trend towards LTE and LTE Advanced, both of which are derivatives of the GSM standard, does suggest that, increasingly, all mobile/cellular handsets will likely have some version of a SIM in the foreseeable future.
But is a SIM really necessary?
Thanks to the convergence that has occurred between mobile/cellular service and Internet, wireless devices, such as smartphones and tablets, can connect to the Internet using technologies such as Wi-Fi. Thereafter, through Voice over Internet Protocol (VoIP) services, such as those offered by Skype, and other similar applications, users can conduct voice calls without connecting to their telecom carrier’s mobile/cellular network.
Furthermore, it must be highlighted that it is also possible to operate a smartphone or tablet without a SIM, that is, using Wi-Fi exclusively. Some manufacturers of tablet computers, in particular, give consumers the option of purchasing a device that either, requires a SIM (or service through a telco); uses Wi-Fi only; or both. However, the price variations between those options can be considerable, since telcos are sometimes prepared to subsidise the price of carrier-dependent devices, on the condition that users are locked into certain contracts for a fixed period of time.
For devices that are designed to use a SIM, the ability to operate without one will depend on, primarily, the make and model of the device, and whether a telco or the manufacturer has implemented any constraint on the device, such as SIM lock. If a SIM lock exists, the device might not be useable until a SIM has been installed.
Key trade-offs when not using a SIM
For smartphones and tablets that accept a SIM, on occasion it might be necessary to use it either without or bypassing the SIM. For those who might be keen to do so, and for devices that use Wi-Fi only, it may be prudent to consider the following pros and cons:
Benefits of Wi-Fi:
- Inexpensive. Typically, the average user does not need to subscribe to a telecoms provider for mobile/cellular or Internet service – someone else might have borne that cost and is prepared to share access to his/her service. Additionally, depending on the software applications being used, calls, web browsing, etc., can be free, or significantly discounted, relative to the rates charged by telcos for their data plans.
- Choice of applications. Users have access to a broad range of software applications, through which desired services can be delivered.
- International mobility. Wi-Fi is a global set of standards (IEEE 802.11 series). Hence it easier to access and use those networks when one travels internationally, unlike other mobile/cellular networks, where different technologies can be used.
Disadvantages of Wi-Fi:
- Limited security. Transmissions on public Wi-Fi networks – those that are not password protected – can be readily intercepted and hence users are frequently advised not to conduct sensitive transactions in those environments. For Wi-Fi networks that are password protected and encrypt transmissions, their secure-ness is dependent, in large part, on the strength of the passwords implemented by network owners/managers. On the other hand, mobile/cellular transmissions are generally considered more secure than Wi-Fi, as carriers have more encryption and authentication options via the SIM and their network configurations.
- Coverage limitations. Unless carriers or local planners have committed to provide Wi-Fi across an entire city, state or country, typically, its availability depends on individual Internet subscribers allowing persons to connect to their wireless networks. Furthermore, Wi-Fi connectivity tends to have a small footprint, for example within a building or covering between 50 to 100 metres outdoors. Hence, persons limited to Wi-Fi are not only dependent on others allowing access to their networks, they also frequently experience less consistent connectivity than persons who, via a SIM, are able to use their carrier’s mobile/cellular network.
Although the Internet might be obviating the need for a SIM, telcos might be more inclined to ensure that it remains since it allows them some measure of control over their customers, especially for billing. Having said this, there are benefits to using devices that require a SIM, such as better security and access to networks that are more cohesive and cover a considerably larger geographic footprint. However, evident by the growing take-up of tablet computers worldwide; the relatively high price of mobile broadband services (e.g. the data plans offered by carriers) particularly in the Caribbean; and the benefits Wi-Fi does offer, Wi-Fi is likely to remain an attractive option for most mobile/cellular customers.