User Association in Heterogeneous Cellular Networks

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Solution Overview

Problem

Existing user association methods in heterogeneous cellular networks are impractical due to the need for accurate pre-known information, are offline and not real-time, and do not consider backhaul capacity constraints, making them unsuitable for dynamic and capacity-limited environments.

Innovation Solution

A method for associating a user with a base station based on backhaul capacity, which involves calculating SINR, available base station sets, usable link capacity factors, and selecting the optimal base station to ensure real-time user association and network performance, using an online algorithm that accounts for backhaul capacity constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If offline optimization algorithms are used for user association, then optimal association solution can be obtained, but the method is not real-time and not applicable to dynamic networks

Engineering Contradiction:
Improveoptimality of association solutionVSAvoidreal-time response speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent transforms the static offline optimization approach into a dynamic online algorithm that adapts to real-time network conditions. The algorithm continuously updates user associations as users arrive and depart, using real-time channel state information and backhaul capacity data to make immediate association decisions without requiring complete prior knowledge of network state.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the problem parameters from requiring complete offline information (all user locations, channel states, and backhaul capacities known in advance) to using only real-time observable parameters (current user set, instantaneous channel states, and available backhaul capacity). This parameter transformation enables real-time implementation while maintaining solution quality.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If accurate information about user location, data rate and base station status is required in advance, then optimal association can be achieved, but such information cannot be obtained in dynamic networks

Engineering Contradiction:
Improveaccuracy of association decisionVSAvoidinformation acquisition feasibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent performs preliminary actions by pre-defining the association algorithm structure and decision rules before users arrive, but leaves the specific association decisions to be made in real-time based on actual network conditions. The algorithm pre-establishes the optimization framework and constraint conditions, then applies them dynamically as users are served.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses self-service by relying on readily available real-time information that the network naturally provides (current user connections, instantaneous signal quality measurements, and monitored backhaul capacity) rather than requiring external information gathering. The algorithm processes this self-generated data to make immediate association decisions.

Inventive Principle:
Principle #25Self-service

3Productivity

If traditional user association methods are used without considering backhaul capacity, then association speed is fast, but backhaul capacity constraints are violated leading to network performance degradation

Engineering Contradiction:
Improveassociation decision speedVSAvoidbackhaul capacity constraint satisfaction
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements feedback by continuously monitoring backhaul capacity utilization and using this information to adjust user association decisions. The algorithm checks whether adding a user to a base station would exceed its backhaul capacity constraint, and adjusts associations accordingly. This real-time feedback loop ensures constraint satisfaction while maintaining fast decision-making.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent makes the association algorithm dynamic by adapting to real-time backhaul capacity conditions. When backhaul capacity is abundant, the algorithm can associate more users to maximize network utility. When backhaul capacity is constrained, the algorithm dynamically adjusts to respect these limits, transforming the static capacity constraints into dynamic decision parameters.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS10085272B2Method for associating a user with a base station based on backhaul capacity in heterogeneous cellular network
Publication Date: 2018.09.25 UNIV OF ELECTRONICS SCI & TECH OF CHINA
  • US10085272B2 patent drawing
  • US10085272B2 patent drawing
  • US10085272B2 patent drawing

AI summary

The present invention provides a method for associating a user with a base station based on backhaul capacity in heterogeneous cellular network. First, an available base station set is obtained through the SINRs, and the downlink data rate between the new user and each base station in the available base station set is calculated according to the SINR between them; Then, the usable link capacity factor of each base station is calculated based on the used link capacity and the backhaul capacity; Finally, the optimal base station is selected for the new user i under a constraint which is constructed by the bandwidth of the new user and the usable link capacity factor. The backhaul capacity of each base station is taken into account in selecting the optimal base station to associate with for the new user, thus the real time of user association and the overall performance of heterogeneous cellular network can be guaranteed.