T-Mobile's WiFi calling service enables customers to use its number for calls over WiFi networks, with calls and text messaging being charged directly to your T-Mobile account and data usage not capped. You can enable WiFi calling by turning it on in your device settings; it works with all Android phones that contain SIM slots that connect to WiFi networks as well as some Skype, WhatsApp and Google Voice applications that may work over Wi-Fi networks.
T-Mobile WiFi calling can help users avoid overage charges, yet it still has some drawbacks. For example, it may disconnect when switching from WiFi to standard wireless service due to weaker or intermittent mobile signals; and voice quality may differ significantly between WiFi networks and traditional cellular signals; which poses challenges when you are constantly on the move and need to switch back and forth between WiFi and cellular service.
Solution to this issue? Tmobile Wifi Calling App for Nexus 5. This app enables users to prioritize calls over WiFi even when signal levels are weak and set call frequency so calls do not disconnect when switching back and forth between WiFi and regular network coverage. Plus, its free availability makes this option an attractive one! It can be found in Android Market.
If you want to use your Nexus 5 with CDMA SIMs, then finding a Sprint MVNO that supports it will be key. Ting currently provides full functionality on Nexus 5, while other Sprint MVNOs such as PTel and Ultra provide reasonable priced talk/text plans with up to 100 MB of data allowances respectively.
One downside of this type of plan is that your prepaid airtime may expire after one year depending on the carrier, although some such as Straight Talk offer plans that offer incentives for paying upfront and an LTE data limit of 2.5GB.
If you're considering switching prepaid services, T-Mobile official prepaid plans offer some of the most comprehensive plans available today. With three tiers and variable talk and data caps per tier - and Nexus 5 support across multiple LTE bands - the official plan offers some excellent choices. T-Mobile's official prepaid plans do not permit roaming or international use, as they were designed with US residents in mind. Furthermore, these plans do not come subsidized so that you must pay upfront. These plans also require an E911 address so that 911 dispatchers can locate you quickly in case of an emergency; either through MyE911 or 911 Caller ID apps on mobile phones or on T-Mobile's website or storefront e911 addresses can also be purchased if desired.
