Vodafone knows it is playing catch up when it comes to 4G after the launch of EE, but it hopes to limit that damage by tempting customers with price deals now ahead of its own launch.Vodafone is offering to knock 70 per cent off current contract deals for anyone taking out the company's own 4G offering. What you need to do is exchange the phone on your current contract, dependent on condition, for a 4G-compatible device. That qualifies you for the discount on the remainder of your current deal, as long as you have been a pay monthly customer for at least three months.On the face of it, a good deal, especially if you have just upgraded and like the idea of a high-speed mobile network when it lands. But there are a few other factors that are likely to come into play, not least the price of 4G on Vodafone.The EE pricing has come under fire, which might have made some people think twice about adopting 4G early. There could be a price war when all the networks have access to 4G, but we would be surprised if the other mobile companies undercut significantly. If you don't happen to be in one of the initial 4G zones, that is likely to put you off too, no matter what the price or discount. Saying that, Vodafone is talking about 98 per cent coverage by the end of 2013, so maybe that will be less of an issue as 2013 progresses.If none of that worries you, the Vodafone deal looks worth a closer look, although you do have time to think about it, with a launch before spring 2013 unlikely.