2 research outputs found
Mechanical relaying in cellular networks with Soft-QoS guarantees
With the tremendous increase in mobile data traffic, system capacity considerations are no longer the primary and only concern to optimize for in cellular networks. The step increase in utilization of cellular networks not only has shorten the recharging cycle of mobile terminals but has further caused a considerable rise in the operators' energy bill. It has therefore become imperative for the sustainable proliferation of such systems to reduce the energy waste and maintain low operation energy cost. As we discuss in the sequel, mechanical relaying is purposefully envisioned to achieve the required performance gains that need to be realized in order to keep up with the exponential increase in data traffic demand. Via mechanical relaying, mobile nodes are able to postpone message communication while in transit and initiate communication only when found at locations within the cell with favorable channel gains. We show that such a scheme offers the possibility to realize innovating relaying strategies that reduce many-fold the system energy consumption and increase the resource utilization efficiency. In this work, both centralized and decentralized solutions that employ mechanical relaying are considered
Techniques for green radio cellular communications
This thesis proposes four novel techniques to solve the problem of growing energy consumption
requirements in cellular communication networks. The first and second part of this work
propose a novel energy efficient scheduling mechanism and two new bandwidth management
techniques, while the third part provides an algorithm to actively manage the power state of
base stations (BSs) so that energy consumption is minimized throughout the day while users
suffer a minimal loss in achieved data rate performance within the system.
The proposed energy efficient score based scheduler (EESBS) is based on the already existing
principle of score based resource allocation. Resource blocks (RBs) are given scores based on
their energy efficiency for every user and then their allocation is decided based on a comparison
between the scores of the different users on each RB. Two additional techniques are introduced
that allow the scheduler to manage the user’s bandwidth footprint or in other words
the number of RBs allocated. The first one, bandwidth expansion mode (BEM), allows users
to expand their bandwidth footprint while retaining their overall transmission data rate. This
allows the system to save energy due to the fact that data rate scales linearly with bandwidth
and only logarithmically with transmission power. The second technique, time compression
mode (TCoM), is targeted at users whose energy consumption is dominated by signalling
overhead transmissions. If the assumption is made that the overhead is proportional to the
number of RBs allocated, then users who find themselves having low data rate demands can
release some of their allocated RBs by using a higher order modulation on the remaining ones
and thus reduce their overall energy expenditure. Moreover, a system that combines all of
the aforementioned scheduling techniques is also discussed. Both theoretical and simulation
results on the performance of the described systems are provided.
The energy efficient hardware state control (EESC) algorithm works by first collecting statistical
information about the loading of each BS during the day that is due to the particular
mobility patterns of users. It then uses that information to allow the BSs to turn off for parts
of the day when the expected load is low and they can offload their current users to nearby
cell sites. Simplified theoretical, along with complete system computer simulation, results are
included.
All the algorithms presented are very straightforward to implement and are not computationally
intensive. They provide significant energy consumption reductions at none to minimal
cost in terms of experienced user data rate