Streaming TV-signal to your mobile device is very easy.
Just install the smartglass app for your device (for example windows phone, windows tablet, android tablet [and with smartglass beta even android smartphones] or iPad, iPod or iPhone). Open and connect it to your xbox one.
Then tap the top left corner and choose "OneGuide" from the menu:
Afterwards you get a windows like this:
Scroll up and down, select the channel you want to watch und easily tap the channel-icon.
Last but not least you can select the quality of the stream. if you have a fast connection you can use "Best Quality" but you can even select "High", "Medium" or "Low" for slower networks. Just click the right icon at the bottom of the screen.