roperability still remains a dream. Not only does in take too much effort and testing to ensure interoperability, but in some cases, it also implies that existing solutions provided by vendors need to be contractually maintainable and have support for further improvements or corrections for interoperability, which may not be the case for many implementations already deployed in the field. All of this ends up adding to the overall cost for deployment and maintenance, especially in some cases when specific vendor solutions need to operate together due to network planning in some particular sites or locations. Tracking such issues and managing them closely are the only options available to the operator to ensure successful deployments and good user experiences when they move between different vendor network elements. Issues Related to Backhaul LTE as a technology has been designed to provide very high speeds on the radio UE side. If we trace back to earlier technologies like 2G or 3G traditionally, the radio, including UE and NodeB, has been the side that has limited networks' throughput. With the removal of that limitation, experts perceived that the attention would shift back to the backhaul for being able to support the required bandwidth. Operators not only need to be able to design the backhaul to be able to support required load generated by LTE terminals with very high data capabilities, but they also need to be able to add required additional capacity as needed by the growing network and subscriber needs. CHAPTER 3 DEPLOYMENT CHALLENGES IN EVOLVING 4G Also, as an improvement in the architecture from 3G, LTE introduces the eNodeB as a single node that collects the functions of both the radio network controller (RNC) and the base station. In 3G networks, operators can plan a layered approach, with the RNCs aggregating the connections to the base stations and then being connected in a limited manner to the backhaul (core network). The LTE collapsing of the radio nodes into the eNodeB has also raised a related r