In what way are cellular network radio frequency bands most significantly different from 802.11 WLAN radio frequency bands?
 
Answer:
 
It is important to understand that the cellular network radio frequency bands are licensed and regulated, but that the 802.11 radio frequency bands (2.4GHz ISM, 5GHz U-NII) are unlicensed and regulated.
 
Question:
 
Why do the newer cellular network technology generationsachieve ever higher performance while newer 802.11 technology generations generally fail to achieve significantly higher performance in spite of the fact that they employ similar new capabilities (e.g., dynamically channel widths (from 20MHz to 40, 80 and 160 MHz), MIMO, MU-MIMO, OFDMA, beamforming, etc.)?
 
Answer:
 
A licensed band is for specific a frequency band subset of channels, in a licensed frequency band, for a specific service area. The license also restricts the service area shape and size, which are determined by the radio antenna radiation pattern and the maximum conducted power per channel. The license also requires that the cellular network access points (base stations) be fixed (i.e., not mobile), which is natural for cell towers. Also, because electro-magnetic waves propagate in a straight line forever (unless blocked by something) but will diverge from the point of the antenna, a channel’s signal power density will decrease as a function of distance from the transmitter in an inverse-square law proportion.  So, in order to prevent co-channel interference, the regulator will only issue licenses for overlapping cells that do not have the same channel frequency sub-bands.
 
Also, while multiple licenses may be issued to different operators for the same service area, each operator effectively has monopoly on a greenfield environment in that service area. Thus, when the cellular network operator upgrades the network in that service area with next-generation equipment and when the cellular network operator leases, sells, etc., next-generation compatible devices (e.g., smartphones) with wireless service set (SS) interfaces with similar capabilities to its customers, the customers will notice a significant improvement in performance with each successive generation of the wireless technology.
 
An unlicensed band is for any person, business, etc. to use without restriction as long as the radio STAs meet the applicable regulations that the radio station component or unit manufacturer must have independently verified, which gives both the regulator and the customer validation that the radio station component or unit meets the regulator’s applicable regulations’ requirements. Note that the regulator does not care if the radio component or unit meets an industry standard’s (e.g., IEEE) requirements. The manufacturer may be capable of doing its own verification and validation that its radio component or unit meets the industry standard’s requirements or it may contract with an independent laboratory to do so.
 
Note: Although a radio manufacturer may be a member of an industry trade association (e.g., Wi-Fi Alliance), which promotes an industry-standard technology and the industry trade association may be capable of verifying a member manufacturer’s radio component or unit compliance with the industry standard, such trade associations do not require their member manufacturers to have their radio component or unit to be verified by the trade association. If such radio components or units are not validated by the trade association, then their manufactures should not brand such non-verified radio components or units with the trade association’s certifying logo. So, the lack of a validating industry trade association logo does not necessarily imply that a radio component or unit has not been verified or that it is not compatible with an industry standard.
 
Unlicensed wireless radio access point (AP) base stations may be located wherever a person or business decides. If that person or business uses an unlicensed wireless radio AP STA unit in a greenfield environment to create a wireless LAN (WLAN) and the client devices associated with the WLAN have wireless radio SS STAs that are of the same generation and have corresponding capabilities as the AP STA, and have use-cases favorable to the device characteristics’ capabilities, then whenever the radio AP STA unit and clients’ radio SSs are upgraded with successive generations of wireless technologies, each successive generation WLAN will have significantly higher performance for favorable use-cases.
 
But, if the person or business uses the same unlicensed wireless radio AP STA to setup a WLAN with the same clients with wireless radio SS STA in an environment where the WLAN’s basic service area (BSA) undoubtedly intersect with a relatively large number (e.g., ten to forty) of WLAN BSAs of other similar unlicensed wireless radio AP STAs and SS STAs. So, if each WLAN has say ten to thirty client devices with associated radio service set (SS) STAs then there certainly will be co-channel interference (CCI) and adjacent channel interference (ACI). The amount of CCI and ACI depends on how the associated clients use the WLAN (when, how, and how much demand will load the WLAN channel). In such general environments and non-favorable use cases, the performance of WLANs with next generation wireless AP STs and SS STAs devices will invariably be little or no better than that of the original practically perfected generation.
 
The cable companies and enterprises had little or no experience with unlicensed radio devices because the coaxial cable-based networks that connect to their customers’ premises and the Ethernet cable networks in those premises can all be considered to be greenfield wide-area networks (WAN) and LANs. This is because there is practically no CCI or ACI in and between cables. If in fact, if some of these cable companies were divisions of companies that also had licensed cellular networks, then those cellular networks also were greenfield networks and so even these companies had little or no experience with unlicensed radio devices. When 802.11g AP STA and then 802.11a AP STA wireless routers were installed in their customers’ premises to create WLANs, the performance and convenience was comparable with respect to Ethernet LANs. (NOTE: at that time, most of the performance issues were not due to the LANs and WLANs but due to bottlenecks in the Internet and the served connected to it.
 
Cable companies have successfully upgrade their WAN coaxial cable based networks through several new generations and so they enthusiastically first upgraded the associated WLAN routers to have 802.11n AP STAs and then second to have 802.11ac AP STAs. However, the cable companies were disappointed that the performance increases of both next generation WLAN equipment upgrades were not what they were led to believe.
 
Looking forward:
 
As described in a recent previous post,  after being fooled twice, some cable companies are determined to be not fooled a third time.  
 
I’ve already provided an explanation, in a recent previous post, why a multi-radio 802.11a/g AP STA unit will out-perform a single-radio AP STA unit under such a range of general environments and demanding use-cases.
 
In later posts (as I find time to write them) I will provide – hopefully – simple descriptions of the desirable features of single-radio 802.11n/ac/ax WLANs that can provide the highest performance gains (i.e., dynamically channel widths (from 20MHz to 40, 80 and 160 MHz), MIMO, MU-MIMO, OFDMA, beamforming, etc., which is the order of higher-to-lower gains) in greenfield environments and favorable use-cases and why they fail to provide little more performance than WLANs with single-radio 802.11a/g AP STAs under a range of general environments and demanding use-cases.