ent infrastructure for the network. The Network Operation Center includes one or more LOCs to serve as an access point from which local content providers can distribute local content to mobile devices in the associated market area FLO Transmitters: Each transmitter transmits FLO waveforms to deliver content to mobile devices. 3G Network: The 3G network can be provided by any CDMA2000 or WCDMA mobile operator. A 3G cellular network is required to provide control functions to support interactivity for purchasing and downloading transactions and facilitate user authorization to the service. Devices: FLO devices are multipurpose devices that serve as telephones, address books, Internet portals, gaming consoles, and SO on. Content Provider Content Provider Content Provider Delivery - National Delivery - Local Delivery - Local (MPEG2) Content Content Internet Transmissions to National Multiplex National + Local Mobile Devices Distribution Distribution to Towers Internet National Ops Local Ops Center Center (NOC) (LOC) Receive Site Transmitters 3G Network 3G Reverse 3G Reverse Link Service Key Distribution, Subscriptions Content Provider Delivery National Figure 9.15 FLO network systematic. Reproduced from C 2009 Qualcomm [25] Next Generation Mobile Communications Ecosystem Upper Layer Control Layers Stream Layer MAC Layer Physical Layer Layer Upper Layer Stream Layer Logical Channels Layer Layer 2 Multiplexing and QOS Delivery Layer 1 Physical Layer Figure 9.16 MediaFLO air interface model. Reproduced from © 2009 Qualcomm [25] 9.12.2.4.2 FLO Air Interface The FLO air interface standard follows the traditional OSI model as shown in Figure 9.16. The TIA 1099 only describes the physical (layer 1 and data link (layer 2) layers. The Data Link layer is further subdivided into two sublayers, namely, Medium Access (MAC) sublayer, and Stream sublayer. The FLO air interface specification does not specify the upper layers to allow for design flexibility in support of various applications and services. These layers are only shown 