Imagine a wave traveling through space, the distance between the waves the wave length, the number of times that wave happens per second the frequencies, so as frequency rises wavelength falls
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Spectrum allocation limited, so a country making most of what they have. LTE had superior download speeds, but it had 450 MHz to 6 GHz frequencies, making RF design for world phones using LTE & later LTE Advanced, so each operator only has about 200 megahertz of allocation to work with, & mobile phone need enhanced mobile broadband, but what about URLLC for important remote robot surgery or robotic V2V communications to prevent accidents that need less than 10 milliseconds latency, but low data rates, but what about streaming video on your phone with low latency or low reliability, these goals are so broad that 5G needed to be flexible, so IEEE tricks that LTE had to do, but something else was needed, namely the millimeter wave region of 70, 80, 80 GHz, the same range as ADAS radar, which could make such problematic, but such high frequencies are sensitive to tiny mechanical shifting typical in tall building installations of network equipment at the higher frequencies, or poll mounted devices for 5G NR such as those rust red colored "Trash Can" mounted 5G towers everywhere.
Your iPhone 16 & grandpa's HAM radio might seem desperate, but they are fundamentally using similar RF radio frequency data broadcasting & reception, transceiver operation, analog or digital encoded. What about the low frequency base band and big antenna that would never fit into a phone, but a higher frequency mixing with a carrier frequency passband of higher and lower sidebands where the data from the baseband encoded, and ratio from high to low the bandwidth, the same reason that higher frequencies get high data throughput, so 10% of 70 GHz seven gigahertz of bandwidth which is much faster than 10% of 6 Ghz or 600MHz.
True mobile phone antenna do not actually emit a 3D bubble, but half loss attenuation means the signal strength gradually reduces as distance increases, but absorption in rain, air, reflection off buildings, the RF Power AMP has to overcome this noise, for clear signals, but in a phone IC that is a power constrained & heat constrained tiny chip space & system compact, so digital to analog & analog to digital, power amp connected to antenna, so is the receiver, forming a transceiver, but path loss proportional to the frequency squared, so higher frequency waves do not travel as well or as far as lower frequencies, but with MMwave spiral shape array antenna up to 32 beam steering into the phone case, the tower also beam steers to the mobile handset. Mixer in the phone & antenna help to separate signals, clean them up, analog then to digital for data to the smartphone or digital to analog for broadcasting data from the phone to the tower.
5G up to 10X faster than LTE if you have a perfect 5G millimeter wave line of sight connection in a mall, airport or stadium, public transport train stations, or areas in large cities with many towers works really fast, but turn away or lose line of sight and LTE 4G way better. Thankfully the RF chip in your smartphone does 3G, 4G & 5G with backwards compatibility functionality, or are poly-frequency, also for NFC & Bluetooth. Multi-frequency RF engineering in a smartphone for mobile data, voice, text, its a nightmare of HAM radio elite engineering excellence IEEE author export level RF design genius. 5G New Radio comes in many standards, and 5G works over LTE Advanced Fallback, but at lower bands it's not much a performance boost. Major Telecoms wanted high bands or green fields without much noise as the lower and mid frequency bands are busy with 3G & 4G legacy functions & other RF sources.
Smartphones are already a mature technology so the confusing branding of 5G, was it the real 5G, the super fast 5G, which 5G does this new phone actually come with. What about that Apple emergency Satellite connection in L up & S down connections. Only US iPhone have MM wave as of 2025 perplexingly. MM wave mostly for fixed wireless access in rural areas. Industry 4.0 initiative have no really panned out for 5G millimeter wave applications. Japan was the only country, during 2020 Olympics, that set up MM Wave 5G network.
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