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The aviation community is currently working on the standardization of data communication systems for the future air traffic management (ATM). The standardization effort has two main streams, namely, standardization of future radio access technologies in the L-band (i.e., LDACS) and standardization of a future IPv6-based aeronautical telecommunications network (ATN/IPS). In this thesis, different handover and radio resource management algorithms are developed for the most promising future radio access technology for the aviation, L-band digital aeronautical communications system option 1 (LDACS1) in conjunction with realistic IPv6-based network layer functionality (ATN/IPS). In the first part of this work, handover performance of network mobility (NEMO) is investigated and different cross-layer approaches are proposed in order to improve handover latency and signaling overhead. These improvements mainly use media independent handover functionality proposed by the IEEE 802.21 standard and are important due to the following reasons: - One of the main system requirements of LDACS is to deliver certain ATS messages in a timely manner (i.e., low latency) with minimum service disruption (i.e., high service availability). - In parallel, future services like VoIP and transmission of sensor data for the aircraft health management also require “real-time” and “near-real-time” transmission of certain information with low latency and high availability. - According to STATFOR statistics, number of flights in Europe will be around 17 million in 2030 annually, which is 1.8 times more than in 2009. Since LDACS is planned for the time frame of 2020-2030, it should be capable of handling the data traffic demands of the future ATM. From this perspective, reducing the signaling overhead over the wireless link should be one of the design criterion for future radio access technologies that will be used in the ATM domain. With our proposals, total handover latency (i.e., layer 2 and layer 3) is reduced from 3 s to around 0.4 s and signaling overhead due to router advertisement messages is reduced from 17 kbit/s to around 0.1 kbit/s. In the second part, the effect of handover event on transmission control protocol (TCP) performance is analyzed. In the first step, different TCP handover optimizations related to Mobile IPv6 protocol are presented. In the next step, the applicability of these proposals to different handover scenarios is investigated and the most promising proposal (home agent buffering method) is integrated with LDACS1 handover functionality. Finally, the performance of home agent buffering method is analyzed in terms of TCP transmission completion time. With the help of this method, total transmission completion time of a session is reduced by at least 10% for a download of 110 kB of information. In the third part, different radio resource management (RRM) algorithms are analyzed for the LDACS1 since the resources should be distributed evenly among different users. This is not only important from fairness perspective but also from “expiration time” and “latency” requirements of ATS/AOS messages. Here, we analyzed different RRM algorithms in terms of bandwidth and end-to-end delay fairness. We also proposed a new modified deficit round robin algorithm which could be used for both links (i.e., forward and return link) and satisfies almost perfect fairness among different number of users. In the last part, different NEMO route optimization (RO) techniques are analyzed due to triangular routing problem of NEMO. With the help of NEMO RO, packets follow shorter paths (in terms of number of hops) between the end nodes so that the measured end-to-end delay is reduced. Most of these NEMO RO methods are published as Internet Engineering Task Force (IETF) drafts. Among those proposals, we have realized that some of them require mobility related functionalities to the end nodes and some others do not. In addition, some proposals try to solve nested NEMO problem without working on the main route optimization problem. In addition, since most of those protocols are published as IETF draft, some proposals lack protocol design and maturity in terms of implementation. Considering these issues, we mainly analyzed infrastructure based NEMO RO techniques; namely global home agent to home agent (global HAHA) and correspondent router (CR) protocols from ATN/IPS perspective in the first part. Later on, we proposed two new approaches for the global HAHA protocol in order to decrease end-to-end delay and mobility signaling overhead.