Buffer Sharing on an OFDMA Downlink

2010-09-30
GİRİCİ, TOLGA
Ozel, Omur
Uysal, Elif
In this work we consider the allocation of buffer space to data streams sharing a common high-speed wireless transmitter. As an example, we focus on an OFDMA-based downlink system scenario. Scheduling for maximum throughput has been extensively studied in the literature. However, the practically interesting case of a finite buffer has not been sufficiently addressed before. Especially in the case of overloaded packet queues, the choice of buffer management policy substantially affects the throughput performance. We consider a physicallayer scheduling scheme that allocates users to subcarriers based on channel state, in order to make the most use of multiuser diversity. We then consider optimal buffer partitioning to accommodate the resulting rates. We study the system throughput by simulations. As a benchmark, we also simulate MaxWeight, a well-known cross-layer channel and queue-aware scheduling policy that is throughput-optimal in the absence of a finite buffer constraint. We observe that a suitable buffer management policy with a simple channel-aware queuing policy achieves cross-layer scheduling performance, and can exceed it.

Suggestions

Broadband loaded dipole antenna design by genetic algorithm optimization
Asan, Bahri; Koç, Seyit Sencer; Department of Electrical and Electronics Engineering (2014)
It is well known that standard dipole antenna is not convenient to be used in broadband wireless communication applications because of its narrow frequency bandwidth. To broaden the bandwidth of a dipole, lumped loading is the generally applied method. Positive effects of resistive, capacitive and inductive loading are discussed and proved for a pretty long time. This thesis investigates broadband lumped loaded dipole antenna design procedure by using genetic algorithm optimization techniques. First, unload...
Scheduling Policies for Minimizing Age of Information in Broadcast Wireless Networks
Kadota, Igor; Sinha, Abhishek; Uysal, Elif; Singh, Rahul; Modiano, Eytan (2018-12-01)
In this paper, we consider a wireless broadcast network with a base station sending time-sensitive information to a number of clients through unreliable channels. The Age of Information (AoI), namely the amount of time that elapsed since the most recently delivered packet was generated, captures the freshness of the information. We formulate a discrete-time decision problem to find a transmission scheduling policy that minimizes the expected weighted sum AoI of the clients in the network. We first show that...
Blind channel estimation based on the Lloyd-Max algorithm innarrowband fading channels and jamming
Dizdar, Onur; Yılmaz, Ali Özgür; Department of Electrical and Electronics Engineering (2011)
In wireless communications, knowledge of the channel coefficients is required for coherent demodulation. In this thesis, a blind channel estimation method based on the Lloyd-Max algorithm is proposed for single-tap fading channels. The algorithm estimates the constellation points for the received signal using an iterative least squares approach. The algorithm is investigated for fast-frequency hopping systems with small block lengths and operating under partial-band and partial-time jamming for both detecti...
Cooperative Multiple-Access in Fading Relay Channels
Yılmaz, Ayşen (2006-06-15)
Virtual antenna arrays can be constructed via relaying even in the case that there is insufficient physical space or other resources for multiple antennae on wireless nodes. When there is a multiple access scenario, relaying offers a variety of ways to establish communication between source and destination nodes. We will compare a scheme based on space division multiple access to previously studied time division based ones. We observe that space division improves especially the ergodic capacity.
Neighbor discovery in network with directional antennas
Bilgin, Yusuf Alper; Yılmaz, Ali Özgür (2013-08-05)
Using directional antennas in wireless networks has become a popular approach due to its benefits. However, since the existing MAC protocols were not designed to work with such antennas, when the existing protocols are used, the network capacity may even deteriorate rather than improve. In this paper, a neighbor discovery algorithm has been proposed for a system using directional antennas. A discovery algorithm proposed by [1] has been studied and its efficiency has been improved by making some changes. Wit...
Citation Formats
T. GİRİCİ, O. Ozel, and E. Uysal, “Buffer Sharing on an OFDMA Downlink,” 2010, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46028.