1. Introduction
Wi-Fi was invented and first released for consumers in 1997 based on the IEEE 802.11, which refers to a set of standards that define communication for wireless local area networks (WLANs). Its basic purpose is to provide broadband internet to a device using wireless transmitters and radio signals, but since then Wi-Fi technology advances have greatly contributed to the Internet of Things and lead to us expecting a standard level of connectivity wherever we go. However the range of Wi-Fi is relatively small which is why a new protocol, WiMAX, was created in 2004. WiMAX is the commercial name for wireless communication standards based on the IEEE 802.16 standards. Unlike Wi-Fi, it allows long range wireless networking for both mobile and fixed connections and can provide voice and video transferring capabilities as well as telephone access. WiMAX has many benefits when it comes to mobility but despite this the global telecommunications industry has chosen to invest fully in other avenues like LTE, meaning WiMAX has never fully taken off. In this essay I will discuss the differences and similarities in the technologies used in Wi-Fi and WiMAX networks, highlighting especially security features. I will then aim to explain why I believe WiMAX never became a replacement for Wi-Fi or was never a strong contender for 4G technologies.
2. Key Differences
There are several key differences between Wi-Fi and WiMAX, the most obvious being the difference in range. A Wi-Fi network reaches around 100 meters at its maximum range, whereas a WiMAX network can reach 80-90 kilometres. However Wi-Fi networks are able to transfer data at up to 54 mbps while WiMAX only exchanges data at speeds of up to 40 mbps. Additionally, WiMAX transfer speeds have more variation because the networks cover a much larger area and the further away from the hub a user is, the slower the transfer rate.
3.1 Wi-Fi Network Components
An access point is the key element in a Wi-Fi network as it is a wireless gateway and bridge between wired and wireless networks. In home networks this tends to be a wireless router. The next element is a distribution system which 802.11 standards define as a combination of bridging engine and backbone network. The distribution system connects access points to the backbone (usually the internet) and also connect different access points over a wired network. It is then the wireless medium which enables the exchange of frames among stations and wired backbones, which in the case of Wi-Fi is radio frequency signals. Lastly in a Wi-Fi network are the stations, or wireless clients, which are all the devices that support Wi-Fi connection.
3.2 WiMAX Network Components
The components of a WiMAX network are similar to that of a Wi-Fi network. Similarly to an access point, the first element of a WiMAX network is an internet connection which acts as the ‘hub’ of the network by providing services to the users on the network. Typically, this is a high speed fibre connection to the internet however in a corporate environment this would be the central data centre that houses the servers and services that the users on the network require. The next element is the primary links which are the ‘backbones’ of the WMAN so must be solid and reliable with a secure power supply, careful installation and planning. The secondary links then provide service from the main network nodes to local distribution points or key customers with high bandwidth requirements.
There are 3 main wireless link technologies used in WMANs. The first is licenced microwave which is ideal for long primary backbone links as it provides high capacity point to point links with predictable throughputs. The second is light licenced radio which can be used for short distance, high capacity, primary backbone links cheaper than licenced microwave alternatives. The third is Wi-Fi which is optimised for short distances, so Wi-Fi systems are probably the most commonly used radio systems.
4. Data Transfer Methods
IEEE 802.11 and IEEE 802.16 use different data transfer methods on their physical layers. The Wi-Fi IEEE 802.11 standards use Multiple Input Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) while the WiMAX IEEE 802.16 standards define two duplex modes: Time Division Duplex (TDD) and Frequency Division Duplex (FDD). This difference is due to Wi-Fi using a connectionless protocol called CSMA/CA, meaning it uses just one frequency channel whilst WiMAX adopts a fully connection-based protocol which uses a scheduling algorithm. MIMO is a technique which enables the sending and receiving of more than one data signal simultaneously over the same frequency channel. In contrast, FDD allows data to be transmitted in one frequency channel and received in another, taking advantage of WiMAX’s dual frequency channels.
5. Security
Security has always been, and probably forever will be, a prominent concern in relation to wireless networks. Early implementations of Wi-Fi networks used the Wired Equivalent Privacy (WEP) encryption standard which was able to be cracked in minutes using standard laptop hardware. Later versions of the IEEE 802.11 standard provided more substantial security and authentication methods in the form of WPA2, which implements more sophisticated data encryption and better user authentication using methods like Temporal Key Integrity Protocol (TKIP) and Counter Mode Cipher Block Chaining Message Authentication Coe Protocol (CCMP). TKIP is an encryption method which uses a message integrity code that enables devices to authenticate that the packets it’s receiving are coming from the claimed source. This authentication is especially important in a Wi-Fi network where traffic can easily be jammed. TKIP also uses a mixing function to defeat weak-key attacks which previously enabled attackers to decrypt traffic. CCMP is a data confidentiality protocol that handles packet authentication as well as encryption and was implemented to be used as a stronger alternative to TKIP on newer hardware.
WiMAX was developed with security in mind and the IEEE 802.16 standard provides strong support for authentication, key management, encryption and security protocol optimisation. Most of the security issues are addressed and handled in the MAC security sub-layer. This includes security association between base stations and their client subscriber stations, a Privacy Key Management Protocol for secure key management and exchange between stations, device/user authentication using RSA-based authentication and Extensive Authentication Protocol and finally the AES algorithm for encryption. However WiMAX networks are still vulnerable to attacks, mainly because security is implemented in the MAC layer, which is above the physical layer, leaving the physical layer unsecure and vulnerable to attacks. A typical threat comes from water torture attacks, in which an attacker captures frames from the networks and replaces them with a series of bogus frames to drain the receiver’s battery or consume computing resources. This attack in particular effects members of society who are users of the network because they’re likely to be using mobile devices that have limited resources. Other attacks that the WiMAX physical layer is vulnerable to are jamming attacks and scrambling attacks which are both where a source of noise is introduced that reduces the capacity of the channel, with a scrambling attack being targeted at specific frames while jamming attacks are unspecific. The types of attacks effect the users of the network by denying service to authorised users as legitimate traffic is jammed by the overwhelming frequencies of illegitimate traffic. It’s also possible that a knowledgeable attacker can easily jam the network in a way that the signal drops to a level where the network can no longer function. As with most networks, there is also the threat that attackers can gain access to people’s personal data through the wireless network. For example, in June 2017, it was found that some WiMAX routers had a vulnerability that allowed hackers to obtain access to the device, reach the network behind it, and spy on the user.
6. Why WiMAX Failed
Despite its security issues, WiMAX seems to overcome some of the problems with Wi-Fi networks, however it is still no where near as widely used and now probably will never get to be. I believe this is because although WiMAX performance exceeds that of Wi-Fi, day-to-day users prefer ease of use and well known technologies to slight technical superiority that most users would not notice. By the time WiMAX technologies came about Wi-Fi was already an integral part of most people’s every day lives, with popular schemes such as Bring Your Own Device (BYOD) allowing employees to use their own devices to access the internet as well as company information and applications through Wi-Fi at the workplace. Although WiMAX’s increased range in comparison to Wi-Fi seems like it would be an attractive advantage to users, it didn’t take long for almost every business, including high street stores, cafes and restaurants, to implement a free Wi-Fi service for it’s users. This means that although most towns and cities do not have a WMAN implemented using WiMAX, users can still gain wireless internet access throughout the majority of urban areas through these public Wi-Fis. Additionally, the first WiMAX phone was not available until 2010[2], 7 years after 3G phones were first introduced in the UK in 2003[3], meaning that by this point the majority of users owned 3G compatible phones. Therefore why would users be willing to buy a new handset that relies on a relatively new technology that was not heavily talked about in the media and that has no stand-out security advantages to technological amateurs. Timing turned out to be a huge issue for WiMAX, as around the time it was released there was also the race for 4G, a very similar solution and technology to WiMAX. Operators who had spent a lot of money in 3G were reluctant to then invest their money in a brand new technology while LTE was potentially only a couple of years away. LTE was an upgrade to an existing technology and therefore would not require consumers to buy new handsets, making it a safe option with users. Another final reason WiMAX never became a replacement for Wi-Fi is due to its much higher cost, which was further highlighted by the fact it was introduced when most homes and businesses already had Wi-Fi networks set up, making it seem even more unnecessary to pay the extra expense.
7. Conclusion
In conclusion, I believe the reason that WiMAX never even came close to becoming as popular as Wi-Fi is due to compatibility. It was introduced at a time where users already had Wireless Local Area Networks set up and had probably only recently invested in smartphones that had Wi-Fi and 3G capability. It therefore made sense for both the operators and consumers to simply stick to the branch of technology that they already knew and, at least partly, trusted rather than to go through the costly expense of converting to WiMAX. It is for these reasons that WiMAX has become a good example of where technology can be a working solution and first on the market but still fail.