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20

what is it that makes it possible for cellular networks to keep getting faster Basically, good old Moore's law. The handset is only half the equation. More modern and powerful silicon does help in getting better channel quality, less noise, etc. However this can't go above the channel bandwidth as per Mr. Shannon. A simple way to boost the bandwidth ...


11

I think following are some of the key technologies/techniques driving up cellular data rates. Move to higher carrier frequencies where wider bandwidths are available. Soon we will have millimeter wave technology being used in cellular. Multi Input Multi Output (MIMO) Antenna systems allowing parallel transmission of data streams. Advance modulation ...


9

I understand that increasing the frequency band means increasing the data rate. You should make a distinction between the frequency band which is sets the frequency range that the cellular signal is supposed to occupy and the bandwith of the signal itself. The frequency band says nothing about the datarate. What does influence the datarate is the channel ...


4

Assuming the same bandwidth, the only way to boost datarates is better coding: QAM versus GSM's MSK, 16QAM versus QAM, 256QAM versus 16QAM, And in all this, multipathing and fading must be handled. With more bits per Hertz, the SignalNoiseRatio (SNR) needs to improve, tho coding provides a one-time 5 or 10 dB assist here. To improve SNR, the link needs ...


3

There is no physical/electrical difference between the SIM cards. It is the economics of the network provider. When a device connects to a cellular network it provides its IMEI (serial number of the device/modem) and IMSI ("number of the SIM card"). Each manufacturer has its range of IMEI numbers, so you can distinguish Simcom, Telit, Quectel, Samsung, ...


3

Another critical advancement that hasn't been mentioned is improved utilization of optical fibre networks. An optical fiber can carry an entire spectrum of wavelengths. They haven't always done so, however. Optical filters of increasing precision now allow dozens (or more) "channels" to now be crammed into single fibers where previously they would have ...


3

Or are we getting better at this in other ways? How so? There will possibly come a day when our handsets (or the system) will be able to store the mathematical nuances of our individual voices and manipulate it to form other words algorithmically. Then all that needs to be transmitted in a voice call is "text" and the receiving phone can reconstruct our ...


2

Turns out that the issue that I was having is that I was not using the commands AT+CGSOCKCONT=1,"IP","CMNET" and AT+CSOCKSETPN=1 before opening the TCP socket. If you are trying to get the SIM5320 to open a transparent TCP connection, the commands you need to send are: AT+CGSOCKCONT=1,"IP","CMNET" AT+CSOCKSETPN=1 AT+CIPMODE=1 AT+NETOPEN AT+CIPOPEN=0,"TCP","...


2

It does not really matter for example if you have two slaves beside the MCU or a slave and a turned off other master. So basically the turned off SIM5360 should not cause any trouble to the MCU given it properly unmounted the SD card before turning itself off, just as @pjc50 has mentioned. Disconnecting the lines of the SIM5360 by a multiplexer controlled ...


2

It's not impossible, but you have to be very careful from a software point of view regarding the filesystem on the card. Each device must flush buffers and unmount the card before "releasing" it to the other device.


2

Not only are designers still coming up with better algorithms to do dynamic audio compression, dynamic channel coding (i.e getting closer to Shannon's limit), and dynamic adaptation to multipath, clutter, and interferers; but as transistors get smaller, we can use more elaborate algorithms for the same amount of battery energy.


1

In theory yes, but in practice no. Besides the firmware, the hardware in the client device is usually set to communicate on only a few frequencies and the transmitter is limited to the uplink frequencies while the receiver circuitry is limited to the downlink frequencies for noise suppression and other reasons. One would have to change the filter circuits, ...


1

Make Sim5360 "master" for the SD card. So it can get dedicated access to the sd card when needed. This can be achieved using some input pin on the uC that is controlled by Sim5360. If uC is not able to write its buffered data to the sd card it just needs to buffer longer or throw some data away. If the amount of data is reasonably small, it can even be ...


1

It's not hard to do what you suggest, it is to all intents and purposes impossible. To make a device that sat between a base-station of one standard and a mobile of another, you would have to build a mobile terminal emulator for the first, a base station emulator for the second, and connect them at the traffic and control layers.


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