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