24 research outputs found
Performance characterization and transmission schemes for instantly decodable network coding in wireless broadcast
We consider broadcasting a block of packets to multiple wireless receivers under random packet erasures using
instantly decodable network coding (IDNC). The sender first broadcasts each packet uncoded once, then generates
coded packets according to receivers’ feedback about their missing packets. We focus on strict IDNC (S-IDNC), where
each coded packet includes at most one missing packet of every receiver. But, we will also study its relation with
generalized IDNC (G-IDNC), where this condition is relaxed. We characterize two fundamental performance limits of
S-IDNC: (1) the number of transmissions to complete the broadcast, which measures throughput and (2) average
packet decoding delay, which measures how fast each packet is decoded at each receiver on average. We derive a
closed-form expression for the expected minimum number of transmissions in terms of the number of packets and
receivers and the erasure probability. We prove that it is NP-hard to minimize the average packet decoding delay of
S-IDNC. We also prove that the graph models of S- and G-IDNC share the same chromatic number. Next, we design
efficient S-IDNC transmission schemes and coding algorithms with full/intermittent receiver feedback. We present
simulation results to corroborate the developed theory and compare our schemes with existing ones
Coalition Formation Game for Cooperative Content Delivery in Network Coding Assisted D2D Communications
Device-to-device (D2D) communications have shown a huge potential in cellular offloading and become a potential technology in 5G and beyond. In D2D networks, the requested contents by user devices (UDs) can be delivered via D2D links, thus offloading the content providers (CPs). In this work, we address the problem of minimizing the delay of delivering content in a decentralized and partially D2D connected network using network coding (NC) and cooperation among the UDs. The proposed optimization framework considers UDs’ acquired and missing contents, their limited coverage zones, NC, and content’s erasure probability. As such, the completion time for delivering all missing contents to all UDs is minimized. The problem is modeled as a coalition game with cooperative-players wherein the payoff function is derived so that increasing individual payoff results in the desired cooperative behavior. Given the intractability of the formulation, the coalition game is relaxed to a coalition formation game (CFG). A distributed coalition formation algorithm relying on merge-and-split rules is developed for solving the relaxed problem at each transmission. The effectiveness of the proposed solution is validated through computer simulation against existing schemes