The one thing I like about the world of Linux in general and also Android is the great number of options. Unlike Windows phone, where there is only one way to perform a task (if at all there is!), android provides a richer user experience in all departments.
Suppose you are traveling to some place and your laptop has lost its usual source of internet connectivity. You will naturally consider surfing the web on your cell-phone, or better still, try and find a way to share the internet on your cell-phone with your laptop, so your work won't suffer.
The android OS supports multiple ways to perform tethering (a.k.a share your mobile internet with other devices such as laptop).
- USB Tethering: I mention this method first because it is the most power-efficient of the lot. Always try to use this method before others if you want to prioritize battery savings. The only shortcoming of this method is that you will only be able to share the mobile internet with at most one device only (in the above example, your laptop). And of course, you will be able to keep your USB cable handy. To use this method, just hook up the USB cable to your laptop (making sure that the device drivers are installed). Then, on your cellphone, go to Settings->Tethering and Portable Hotspot and tap on the USB Tethering option to activate it. (On your particular model, the actual setting name might differ as each manufacturer customizes android to their own liking)
- Bluetooth Tethering: This method is less efficient than USB tethering, but still quite efficient compared to others. Again, the disadvantage is that at most only one peer can be shared. Also, the speed will be much slower compared to Wifi and other techniques, but if 10mbps is workable for you, then this option could be a great help for you. To activate, tap on this option in Settings->Tethering and Portable Hotspot.
- Wifi Access Point: This method is the most common of the lot as the concept of turning your cellphone into a Wifi access point has turned into quite a fad nowadays. However, it is also the least efficient energy wise. The advantage, of course, is that your cellphone can provide its bandwidth to multiple devices at the same time. To activate, tap on this option in Settings->Tethering and Portable Hotspot.
- Using a USB Dongle as Mobile broadband: This method applies only to GSM radios (not CDMA as they are locked by providers). Though it doesn't come under the definition of tethering, the effect is same. If none of the above methods work for you (or for some reason, you don't want to use), as an alternative, you can take out the SIM card and put it in an unlocked USB dongle (also called Data Card). Data Cards are manufactured by companies like ZTE and Huawei and unlocked versions are available in many online retail stores.