“OK! We’ve got you checked in @ Restaurant XYZ. Your phone thinks you’re a little far from Restaurant XYZ, so no points or badges for this checkin. Sorry!”

But, I’m ALREADY in the restaurant, eating my edamame and drinking my mojito!

If you are familiar with the situation above, you’re probably like me—one of those people with a smartphone who’ve jumped onto the bandwagon of using foursquare, the latest buzz in mobile social applications. If you’re not familiar with foursquare, it’s a location-based game that allows users to earn points by checking into venues and to earn a “mayorship” title if you are the most frequent patron of a venue (on foursquare, that is). The message above was (understandably) put in place by foursquare in their attempt to crack down on cheaters by preventing invalid check-ins outside the immediate vicinity of the venue.

In the first installment of this blog I said I’d adjust the topic based on reader feedback. As we prepare for 4G, certain RF testing topics keep coming up, so I’m going to derail our topic thread.

By the way, while I do appreciate your emails (most of them, anyway… as to the others, you know who you are...), some good questions and comments might have stimulated useful conversations had they been shared publicly. We ask for contact info when you comment, but we won’t release that to anyone. Also, unless I have your clear permission, I will not publicly share anything that’s emailed to me. So in the interest of sharing information and questions, I’d urge you to please use the Comments section below.

Our last posting [Weighing the Options – Three Approaches for Testing Real-World A-GPS Performance] discussed approaches for testing real-world A-GPS performance, ending with a recommendation for a lab-based simulation approach. With its repeatable environment, easy setup, fast test times, automated result collection and enhanced handset performance benchmarking capabilities, lab simulation certainly sounds like a great idea, right? Well actually, of the three approaches we discussed, lab simulation is not the most widely used. Why is this?

For starters, real-world lab simulation is really hard to do correctly. Accurately simulating a handful of moving satellites transmitting wirelessly to a moving receiver while signals are distorted, reflected, and obstructed by moving objects and changing atmospheric conditions is enormously complex. In fact, it has been Spirent’s business for the past 20 years or so to do exactly this, and we’ve struggled with it too!