User-level performance of channel-aware scheduling algorithms in wireless data networks

Channel-aware scheduling strategies, such as the Proportional Fair algorithm for the CDMA 1xEV-DO system, provide an effective mechanism for improving throughput performance in wireless data networks by exploiting channel fluctuations. The performance of channel-aware scheduling algorithms has mostly been explored at the packet level for a static user population, often assuming infinite backlogs. In the present paper, we focus on the performance at the flow level in a dynamic setting with random finite-size service demands. We show that in certain cases the user-level performance may be evaluated by means of a multi-class Processor-Sharing model where the total service rate varies with the total number of users. The latter model provides explicit formulas for the distribution of the number of active users of the various classes, the mean response times, the blocking probabilities, and the mean throughput. In addition we show that, in the presence of channel variations, greedy, myopic strategies which maximize throughput in a static scenario, may result in sub-optimal throughput performance for a dynamic user configuration and cause potential instability effects

SINR-based k-coverage probability in cellular networks with arbitrary shadowing

We give numerically tractable, explicit integral expressions for the distribution of the signal-to-interference-and-noise-ratio (SINR) experienced by a typical user in the down-link channel from the k-th strongest base stations of a cellular network modelled by Poisson point process on the plane. Our signal propagation-loss model comprises of a power-law path-loss function with arbitrarily distributed shadowing, independent across all base stations, with and without Rayleigh fading. Our results are valid in the whole domain of SINR, in particular for SINR<1, where one observes multiple coverage. In this latter aspect our paper complements previous studies reported in [Dhillon et al. JSAC 2012]

Packet Scheduling Algorithm with QoS Provision in HSDPA

[[abstract]]The 3rd generation WCDMA standard has been enhanced to offer significantly increased performance for packet data. But coming application like multimedia on desiring data rates will spur the UMTS can support. To support for such high data rates, high speed downlink access (HSDPA), labeled as a 3.5G wireless system , has been published in UMTS Release05. Under the HSDPA system, have to support high speed transmission and promises a peak data rate of up to 10 Mb/s. To achieve such high speed rate, system provides the channel quality indicator (CQI) information to detect the air interface condition. Then, there are many channel condition related scheduling schemes have been proposed to attend achievement of high system performance and guarantee the quality-of-service (QoS) requirements. However, there is no solution of packet scheduling algorithm can consider differences of data-types priority management under the hybrid automatic repeat (H-ARQ) scenario. In this paper, we propose the weight combination packet scheduling algorithm to target to enhance the system efficiency and balanced QoS requirements. The proposed schemes is simulated with OPNET simulator and compared with the Max CIR and PF algorithms in fast fading channel. Simulation result shows that the proposed algorithm can both effectively increase the cell throughput and meet userpsilas satisfaction base on QoS requirements.[[conferencetype]]國際[[conferencedate]]20090526~20090529[[iscallforpapers]]Y[[conferencelocation]]Bradford, U

How user throughput depends on the traffic demand in large cellular networks

Little's law allows to express the mean user throughput in any region of the network as the ratio of the mean traffic demand to the steady-state mean number of users in this region. Corresponding statistics are usually collected in operational networks for each cell. Using ergodic arguments and Palm theoretic formalism, we show that the global mean user throughput in the network is equal to the ratio of these two means in the steady state of the "typical cell". Here, both means account for double averaging: over time and network geometry, and can be related to the per-surface traffic demand, base-station density and the spatial distribution of the SINR. This latter accounts for network irregularities, shadowing and idling cells via cell-load equations. We validate our approach comparing analytical and simulation results for Poisson network model to real-network cell-measurements

Upstream content scheduling in Wi-Fi DenseNets during large-scale events

The smartphone revolution and widespread availability of wireless LAN and mobile Internet technologies has changed the way people interact with the world. These technologies can be exploited by event organisers to boost audience involvement and immersion, for example, by integrating user-generated content into the event experience. In this paper, we developed a large-scale event participation platform for the wireless transmission of user-generated videos to be used during the event. Such events often bring together thousands of users on a small geographical area and providing wireless connectivity in such dense environments is highly challenging. We analysed the efficiency of several upload scheduling strategies in WiFi DenseNets based on extensive experiments performed in a shielded lab environment. We showed that intelligent scheduling improved throughput over 20% compared to uncoordinated uploading in a dense network, with more expected gains when the density would further increase. Moreover, we also calculated the theoretical scalability of the platform. Based on our results, we confirm the importance of content scheduling to efficiently utilise WLAN technologies in highly dense environments

What frequency bandwidth to run cellular network in a given country? - a downlink dimensioning problem

We propose an analytic approach to the frequency bandwidth dimensioning problem, faced by cellular network operators who deploy/upgrade their networks in various geographical regions (countries) with an inhomogeneous urbanization. We present a model allowing one to capture fundamental relations between users' quality of service parameters (mean downlink throughput), traffic demand, the density of base station deployment, and the available frequency bandwidth. These relations depend on the applied cellular technology (3G or 4G impacting user peak bit-rate) and on the path-loss characteristics observed in different (urban, sub-urban and rural) areas. We observe that if the distance between base stations is kept inversely proportional to the distance coefficient of the path-loss function, then the performance of the typical cells of these different areas is similar when serving the same (per-cell) traffic demand. In this case, the frequency bandwidth dimensioning problem can be solved uniformly across the country applying the mean cell approach proposed in [Blaszczyszyn et al. WiOpt2014] http://dx.doi.org/10.1109/WIOPT.2014.6850355 . We validate our approach by comparing the analytical results to measurements in operational networks in various geographical zones of different countries