Main article: Multi-user MIMO. Recently, results of research on multi-user MIMO technology have been emerging. While full multi-user MIMO (or network MIMO) can have a higher potential, practically, the research on (partial) multi-user MIMO (or multi-user and multi-antenna MIMO) technology is more active.
There are two ways to decline a call on the iPhone. 1  By pressing the Sleep/Wake button. 2  By tapping the 'Decline' button onscreen (appears only when the phone is unlocked, as you've mentioned)
When avoiding telephone calls, it is often obvious to the person attempting to reach you. This is especially true if her calls are always routed to your voice mail box, or if the phone continuously rings with no answer. One way to make your avoidance less obvious is to reject the calls with a busy signal. Instead of hearing a ring, the caller automatically hears a busy signal, alerting her that your telephone line is in use. You have the option to reject specific calls or reject all calls. Visit your SmartPhone's App Store..