algorithms for resource allocation in hetnet jianwei liu clemson university
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Algorithms for Resource Allocation in HetNet
Jianwei LiuClemson University
What is used currently
Only in single cellular network. Associate with the best signal BS.
Paper 1-GPF
Paper 1-GPFGeneralized Proportional Fair:
Note there assumptions:• Rate is related to Qa, which is the number of users connecting
to the same BS. • All users must be admitted.• Every user can only connect to exactly one BS. (It’s not HetNet)• User can consume whatever is allocated to him/her. • Only consider downlink.
Paper 1-GPFGPF 1:
Paper 1-GPFGPF 2:
Paper 1-GPFGeneralized Proportional Fair Contributions:
Proved GPF1 is NP-hard(by mapping to 3d matching problem)
Proved GPF 1 is inapproximable.
Provided an optimal offline algorithm for GPF2.
Provided an local search algorithm, but may not work for some cases.
Provided Greedy algorithms. Greedy-0 and Greedy-k.
Paper 2-MotaMOTA assumptions:• Users can use interfaces simultaneously. (run multiple
applications) But, one application can only use one interface/RAT.
• For each RAT, one user can only choose one carrier.• Every application has a weight. It depends on application class.
It kind of reflects the bandwidth demand of one application.
Paper 2-Mota
Paper 2-MotaAlgorithm:
Paper 3-Minimize DelayProblem Formulation:
Try to minimize the sum-delay in downlink of cellular networks
Show it can be linearized by using HST embedding.
The solved problem is kind of changed.
Paper 3-Minimize DelayProblem Formulation:
What Future network will look like
Motivations:From the application perspective: M2M, Internet of Things, various types of applications
Some of them are real-time, need QoS guarantee
CVT applications, delay requirement
From the network perspective:Picocell, femtocell, relay based offloading, SDN based offloading.
(will add citations)
Problem of QoS in the LTE cellular system (https://www.sandvine.com/downloads/general/whitepapers/quality-of-service-in-lte-long-form.pdf)
What Future network will look like
Motivations:From the application perspective: M2M, Internet of Things, various types of applications
Some of them are real-time, need QoS guarantee
CVT applications, delay requirement
From the network perspective:
Picocell, femtocell, relay based offloading, SDN based offloading, WiFi offloading, HetNet, cooperation of different carriers.
(will add citations)
Problem of QoS in the LTE cellular system (https://www.sandvine.com/downloads/general/whitepapers/quality-of-service-in-lte-long-form.pdf)
What Future network will look like
Assumptions1) The traffic we deal with are all demand-aware traffic.
2) We assume every user can use up to C inter interfaces.
For example, we limit the C inter to 3 in our simulation.
4) Every application will choose or be classified to an
application class (ACS), which has known delay from
the cellular gateway. We represent the application classes
as T 1 , ..., T t , ..., T c .
5) The rate of application i using interface j depends on
the location p where the user operates the application i
is, and the SINR at p.
R(i,j,f) = log(1 + SINR(p)) * bandwidth allocated
The total rate of one application get based on assignment
f is:
R(i, f) = j R(i, j, f )
Rationale• Delays need to be guaranteed• Some application demands can be known, like videos • Try to maximize spectral efficiency. • Try to balance the load of BSs. (why, congestion,
assume they are well distributed, will increase the chance of being admitted).
• Try to Minimize the averaged number of interfaces used. Or limit it to a constant. – Good signal – use just one interface– Bad signal – use multiple
Problem Formulation
Proposed Resource Allocation Algorithm
1. Every application sends request to BS every T_interval
2. BS will calculate the estimated congestion ratio.
3. Central Resource Allocation Server (RAS) get reports from all the BSs.
(The reports contains both congestion ratio, and all the link status, and application requests)
4. RAS finds a proper average load ratio Avg_ratio for this T_interval
5. RAS design a scheduling scheme, and send them back to BSs
If BS’s Est_ratio > Avg_ratio, rank users based on their SINR in the list of every BS. Notify (Est_ratio – Avg_ratio) + c% users offload their traffic to a second interface.
The offloading will be simulated, and converge to a solution with certain
threshold