http://www2.ece.ohio-state.edu/~shroff/journal/Liu03a.pdf

A framework for opportunistic scheduling in wireless networks

This article discusses downlink resource allocation and scheduling for OFDM-based broadband wireless networks. We present a cross-layer resource management framework leveraged by utility optimization. It includes utility-based resource management and QoS architecture, resource allocation algorithms, rate-based and delay-based multichannel scheduling that exploits wireless channel and queue information, and theoretical exploration of the fundamental mechanisms in wireless resource management, such as capacity, fairness, and stability. We also provide a solution that can efficiently allocate resources for heterogeneous traffic with diverse QoS requirements.

Utility-based resource allocation and scheduling in OFDM-based wireless broadband networks

Emerging spread spectrum high-speed data networks utilize multiple channels via orthogonal codes or frequency-hopping patterns such that multiple users can transmit concurrently. In this paper, we develop a framework for opportunistic scheduling over multiple wireless channels. With a realistic channel model, any subset of users can be selected for data transmission at any time, albeit with different throughputs and system resource requirements. We first transform selection of the best users and rates from a complex general optimization problem into a decoupled and tractable formulation: a multiuser scheduling problem that maximizes total system throughput and a control-update problem that ensures long-term deterministic or probabilistic fairness constraints. We then design and evaluate practical schedulers that approximate these objectives.

/pdf/opportunistic-fair-scheduling-over-multiple-wireless-2k7t0yr16e.pdf

Opportunistic fair scheduling over multiple wireless channels

With an abstraction of serving rate-adaptive sources on a broadcast-type wireless channel as a utility maximization problem, it is shown how one can design many intuitive online scheduling policies based upon the feedback that one obtains at the scheduler. Using a stochastic approximation argument it is then shown that the constructed algorithms converge to optimal solutions of the utility maximization problem over different sets which critically depend on the quality of the feedback information.

/pdf/optimality-of-certain-channel-aware-scheduling-policies-5bgw21gkin.pdf

Optimality of Certain Channel Aware Scheduling Policies

We identify properties of optimal scheduling schemes for downlink traffic in a code division multiple access (CDMA) data-only network. Under idealised assumptions, we show that it is optimal for each base station to transmit to at most one delay-tolerant user at a time. Moreover we prove that a base station, when on, should transmit at maximum power for optimality. For a linear network, we characterise the optimal schedule as the solution to a linear program. As a by-product, our analysis yields bounds on throughput gains obtainable from downlink scheduling.

/pdf/downlink-scheduling-in-cdma-data-networks-2krp652und.pdf

Downlink scheduling in CDMA data networks

Next-generation wireless networks are expected to support a wide range of high-speed data services, with Web browsing as one of the major applications. Although high data rates have been shown feasible in a single-user setting, the resource allocation issues that arise in a multiple-user context remain extremely challenging. Compared with voice, data traffic is typically more bursty, while the users are less sensitive to delay. These characteristics require resource allocation strategies to operate in a fundamentally different manner if the spectrum is to be used efficiently. In this paper we propose several algorithms for scheduling the efficient transmission of data to multiple users. As a new feature, the various schemes exploit knowledge of the buffer contents to achieve high throughput, while maintaining fairness by providing quality of service (QoS) to individual users. The proposed algorithms are backward compatible with existing cellular and personal communications services (PCS) standards such as IS-136. They provide a powerful approach to improving spectrum efficiency in forthcoming high-speed data cellular services. The extensive simulation experiments we present in this paper demonstrate that the algorithms significantly outperform conventional schemes.

https://www.ee.columbia.edu/%7Epredrag/mypub/DCA_BLTJ98.pdf

Dynamic bandwidth allocation algorithms for high-speed data wireless networks

MultiMedia Communications eXchange (MMCX), a new offering from Lucent Technologies, supports mixed media calling between end points on a local area network (LAN), such as Windows∗-based personal computers and any H.323 standards-compliant end point (for example, an Internet phone). The MMCX client/server architecture also provides access to the wide area network (WAN), allowing LAN end points to call users on other networks. The MMCX enables users to communicate and collaborate in a manner that best suits their needs by supporting multiparty conferencing with any type and combination of mixed media. MMCX calls can consist of any mix of voice, data, image, and video media types, with at least one of the calling/called parties directly connected to a packet transmission and/or switched network. A party to the call may be using one or more communications media, but it is not necessary for all parties on a multiparty conference call to be using the same media mix. For example, three parties may be communicating visually using LAN-connected desktop computers equipped with a videoconferencing option (audio and video), and a fourth party may be conferenced via a telephone, but he or she may only be able to speak and listen to the other parties on the call. To provide high-quality real-time mixed media collaboration in a LAN and WAN environment, important performance requirements for packet delays (such as call post-dialing delays) and media blocking must be met. This paper presents an overview of the MMCX and its performance analysis. A design tool based on our analysis has been developed to run in a PC/Windows-based environment that can be used interactively to design and reconfigure MMCX-based networks.

An overview of the multimedia communications exchange (MMCX) and its performance characterization

MultiMedia Communications eXchange (MMCX), a new offering from Lucent Technologies, supports mixed media calling between end points on a local area network (LAN), such as Windows*-based personal computers and any H.323 standards-compliant end point (for example, an Internet phone). The MMCX client/server architecture also provides access to the wide area network (WAN), allowing LAN end points to call users on other networks. The MMCX enables users to communicate and collaborate in a manner that best suits their needs by supporting multiparty conferencing with any type and combination of mixed media. MMCX calls can consist of any mix of voice, data, image, and video media types, with at least one of the calling/called parties directly connected to a packet transmission and/or switched network. A party to the call may be using one or more communications media, but it is not necessary for all parties on a multiparty conference call to be using the same media mix. For example, three parties may be communicating visually using LAN-connected desktop computers equipped with a videoconferencing option (audio and video), and a fourth party may be conferenced via a telephone, but he or she may only be able to speak and listen to the other parties on the call. To provide high-quality real-time mixed media collaboration in a LAN and WAN environment, important performance requirements for packet delays (such as call post-dialing delays) and media blocking must be met. This paper presents an overview of the MMCX and its performance analysis. A design tool based on our analysis has been developed to run in a PC/Windows-based environment that can be used interactively to design and reconfigure MMCX-based networks.

K. G. Ramakrishnan

Papers

Dynamic bandwidth allocation algorithms for high-speed data wireless networks

An overview of the multimedia communications exchange (MMCX) and its performance characterization

An overview of the Multimedia Communications eXchange (MMCX) and its performance characterization : Packet networking