3rd International ICST Workshop on Resource Allocation in Wireless Networks

Research Article

On Downlink Capacity of Cellular Data Networks with WLAN/WPAN Relays

  • @INPROCEEDINGS{10.1109/WIOPT.2007.4480086,
        author={Bozidar Radunovic and Alexandre Proutiere},
        title={On Downlink Capacity of Cellular Data Networks with WLAN/WPAN Relays},
        proceedings={3rd International ICST Workshop on Resource Allocation in Wireless Networks},
        publisher={IEEE},
        proceedings_a={RAWNET},
        year={2008},
        month={3},
        keywords={Cellular networks  Downlink  Frequency  Land mobile radio cellular systems  Local area networks  Physical layer  Relays  Resource management  Telecommunication traffic  Wireless LAN},
        doi={10.1109/WIOPT.2007.4480086}
    }
    
  • Bozidar Radunovic
    Alexandre Proutiere
    Year: 2008
    On Downlink Capacity of Cellular Data Networks with WLAN/WPAN Relays
    RAWNET
    IEEE
    DOI: 10.1109/WIOPT.2007.4480086
Bozidar Radunovic1,*, Alexandre Proutiere2,*
  • 1: Microsoft Reseach, 7 JJ Thomson Avenue, Cambridge, CB3 OFB, UK
  • 2: KTH COS / Radio Systems Electrum 229, 16440 Kista, Sweden
*Contact email: bozidar@microsoft.com, alexandre.proutiere@radio.kth.se

Abstract

We consider the downlink of a cellular network supporting data traffic. In addition to the direct traffic from the base-station, each user is equipped with the same type of 802.11-like WLAN or WPAN interface that is used to relay packets to further users and hence to improve the performance of the overall network. We are interested in analyzing what are the design guidelines for such networks and how much capacity improvements can the additional relay layer bring, in comparison to cellular networks. We consider a realistic dynamic setting where users randomly initiate downloads and leave the system upon transfer completion. A first objective is to provide a scheduling/relay strategy that maximizes the network capacity, which is the traffic in bit/s/cell that the network can support. We find that, regardless of the spatial traffic distribution, when the cell approaches saturation (the number of active users is large), the capacity-achieving strategy divides the cell into two areas: one closer to the base-station where the relay layer is always saturated and some nodes receive traffic through both direct and relay links, and the further one where the relay is never saturated and the direct traffic does not exist. We further give a simple algorithm to calculate the cell capacity. The obtained capacity is shown to be independent of the cell size (unlike in traditional cellular networks), and it is 20% -60% higher than already proposed relay architectures.