At this point, having a good WiFi solution of your event will be simply the only option. Before, internet may have simply been a good option, but now, it is assumed that you will have the best convention center internet providers so that your connection will be robust and reliable.
A good option for this will be Trade Show Internet. Many facilities will offer you their own technology for internet delivery, but because they are hard-wired, they may be difficult to upgrade. They can also be more expensive than you were planning, since they will often be the default solution for many planners, and so venues can charge more for them than they are really worth.
Trade Show Internet has portable solutions, including the Xirrus WiFi system which is a premier system specially designed for large events. They have services across the country in major cities. For more information, go to their website at www.tradeshowinternet.com.