Network-assisted resource management for wireless data networks Xiaoxin Qiu Kapli Chawla Justin...

Network-assisted resource management for wireless data networks

Xiaoxin Qiu Kapli ChawlaJustin C.-I. Chuang

Nelson SollenbergerJuly, 2001

IEEE Journal on Select Areas in Communications

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Prolog Next generation Wireless system will

provide packet data based service with low cost and high spectrum efficiency

So, the efficient radio resource management is important！

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Outline

Introduction Earlier Resource Management

Network-Assisted Resource Management NA-LI-DPA and NA-DPA with Max Throughput

Simulation Results and Analysis System model Compare with RPA

Conclusion

Network-assisted resource management for wireless data networks

Introduction

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Intro. (1/5) FCA (Fixed Channel Assignment)

A area is partitioned into a number of cells

A number of channels are assign to each cells

Can’t adapt to traffic conditions and user distribution

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Intro. (2/5) DCA (Dynamic Channel

Assignment) The main idea is to evaluate the cost

of using each candidate channel, and select the Min. cost channel

Most DCA algorithms are designed efficient for voice

Reference from IEEE Personal Communication, June 1996

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Intro. (3/5) DPA (Dynamic Packet Assignment) Algorithm

1.MS looks to the STRONGEST BS. 2.BS broadcasts destination MS IDs and numbers

of packets to be delivered 3.MS scans all DOWNLINK pilots and sends list of

acceptable channels to BS 4.BS assigns channels to all packets and

broadcasts MS IDs, assigned channels 5.BS delivers packets on the assigned channels

and sends pilots.

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Intro. (4/5)

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Intro. (5/5)

Reference from:IEEE J. Select. Area Commum. Aug 1998

Network-assisted resource management for wireless data networks

Network-Assisted Resource Management

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Network-Assisted Least-interference-based DPA (1/2)

Idea： For BS to calculate the SINR Need： channel occupancy and path

loss How to calculate SINR：

P:power Gii和Gji:path loss

Qjk:channel occupancy ni:noise

ijijkji

iii nQPG

PGk)(

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Network-Assisted Least-interference-based DPA (2/2)

A channel with a MAX SINR is assigned to the user

Transmission mode depend on link quality

Optional Enhancement with Mode-0 NA-LI-DPA+ In interference-limited wireless data network

))(1(max

...1ikk

NkBLERRmi

m

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Network-Assisted DPA with MAX throughput (1/3)

Idea： Optimize the overall links Need： channel occupancy and path

loss(2) Throughput:

T: system throughput

A: current resource assignment

uN

i i ATAT1

)()(

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Network-Assisted DPA with MAX throughput (2/3)

Algorithm: 1. 計算現在的 T(A) and A :(resource assignmen

t) 2. 計算 user i 的 Ai （ k ） at channel k

Ai =( ci, mi, P)T（調整 mi後） 3. 計算 T(A⊕Ai(k)) 以求出最好的 throughput

AiOPT = arg (max Ai （ k ） (T(A⊕Ai(k)))

最後的選擇： T(A⊕AiOPT)

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Network-Assisted DPA with MAX throughput (3/3) 判斷式：

Reassign an existing user: Ex: To different channel Starting assignment = iAA

otherwiseA

ATAATifAAA

opti

optinew

,

)()(,

Network-assisted resource management for wireless data networks

Simulation Results and Analysis

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System Model Traffic： best-effort

data（ downlink） PHY layer: EGPRS-like frame structure Modulation

B-O-QAM (Binary-offset QAM) Q-O-QAM (Quaternary-offset QAM)

Link layer:RLC/MAC sub layer（ EGPRS）

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Transmission Mode

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Performance Result (1/4) Average user throughput (1/2)

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Performance Result (2/4) Average user throughput (2/2)

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Performance Result (3/4) Aggregate throughput per site

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Performance Result (4/4) Average number of users per

site

Network-assisted resource management for wireless data networks

Conclusion

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Conclusion (1/2) FCA 、 DCA 、和 DPA 的介紹 NA-LI-DPA 和 NA-DPA with MAX throughput Idea: 利用 Inter-base signal 來將 resource a

llocation 的負擔從 air interface or terminal 轉移到 Backbone 和 BS

Terminal just calculate path loss SINR 和 channel occupancy 交給 BS

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Conclusion (2/2) Just for single service （ downlink data ） Advantage:

提升 throughput 和減低 terminal 的負擔 Question:

Power control ? Bandwidth for inter-base signal Integrate voice and data ? Does it suitable for another system?