u-tdoa toa positioning for ieee 802.16m (c80216m-10_0221)

7/31/2019 U-TDOA TOA Positioning for IEEE 802.16m (C80216m-10_0221)

1/22


2/22


3/22


4/22


5/22

5

Reasons for Network-based Positioning (2/2)

For scenarios wherein there are many AMSs requesting LBSin a short time or with high accuracy, handset-based

positioning is a better choice

However, for other scenarios, network-based positioning ismore efficient and introduces less complexity to the system


6/22

6

Problems in D4

In D4, only the following text about network-basedpositioning is mentioned and the description is not clear

AMS and ABS capability to enable measurement of RTD based on

ranging channel transmission (U-TDOA and TOA) (see Subclause

6.3.25)

There are currently two types of ranging channel and the above textdoes not specify which type

According to D4, both types of ranging channel allocation are

contention-based so its unlikely for AMS to meet E911requirement due to intra-cell interference

Only the allocation for initial ranging, handover ranging, periodic

ranging is mentioned in D4 and all are contention-based


7/22

7

Definition of Terminology

TOA measurement algorithm

The algorithm used to measure the TOA of the positioning reference signal sent

by the target AMS to the serving/neighbor ABSs. The TOA measurements can

be transformed to the distances between the target AMS and the

serving/neighbor ABSs.

Positioning algorithm

The algorithm which computes theposition of the target AMS using TOAmeasurements.

If TOA measurements are used for the computation of position, it is called U-

TOA positioning algorithm.

If relative differences of TOA measurements are used for the computation of

position, it is called U-TDOA positioning algorithm.


8/22

8

Proposed U-TDOA/TOA Positioning Mechanism (1/4)

Scenario #1:

Serving cell interference: noneCooperative neighboring cell interference: none

One reference signal transmission for one TOA measurement Physical ranging channel for non-synchronized AMSs is utilized as reference signal for

uplink TOA measurement

Dedicated radio resource for one AMS so as to suppress intra-cell interference An assignment A-MAP is used to allocate the radio resource to a specific AMS for LBS

ranging

Dedicated radio resource among cooperative cells so as to suppress inter-cellinterference Inter-BS coordination is used to silence the radio resource for LBS ranging in

cooperative cells

More than one TOA measurements can be conducted over a period of time toimprove positioning result The number of TOA measurements can be adjusted by serving BS and broadcasted to

MSs e,g,: the adjustment is based on current traffic load

The number of TOA measurements can be fixed and predefined in the system


9/22


10/22


11/22

11

Proposed U-TDOA/TOA Positioning Mechanism (4/4)

Network or Serving ABS Initiation

MS Serving BS Cooperative BSs

Select cooperative BSs

Necessary Information for Positioning

Radio Resource Allocation for Positioning

Positioning Reference SignalSame Time

Instant Reference Signal

Detection & TOA

Measurement

Reference Signal

Detection & TOA

Measurement

TOA Measurement Results

Positioning

Positioning Results

1

2

3

4 55

Repeat Step

3~6 Several

Times

Repeat Step

3~6 Several

Times

Repeat Step

3~6 Several

Times

6

7

8

9

Network-based Positioning

is initiated by the Network


12/22


13/22

13

Text Proposal


14/22


15/22

15

Serving ABS and two neighbor ABSs cooperate to perform positioning

Format 0 non-synchronized ranging signal is transmitted by the AMS to be

positioned

Code index of Zadoff-Chu sequence adopted by the AMS is known to the serving

and neighbor ABSs

Serving and neighbor ABSs execute TOA measurements for the ranging signal

transmitted by the AMS U-TDOA/TOA positioning is computed using algorithm [4] based on TOA

measurements of serving and neighbor ABSs

Block diagram of TOA measurement algorithm is shown in the figure below

TOA Measurement Algorithm

RangingSignal

Timing

LPF RCPRemoval

FFT Extraction ofRanging Code

ZeroPadding

IFFT PeakTest

ObtainTiming

Ranging CodeRCP: Ranging Cyclic Prefix


16/22


17/22


18/22


19/22


20/22


21/22


22/22

22

References

[1] IEEE C80216m-09/2086, Evaluation of D-TDOA Positioning

[2] IEEE P802.16m/D4. DRAFT Amendment to IEEE Standard for Local and

metropolitan area networksPart 16: Air Interface for Broadband Wireless Access

SystemsAdvanced Air Interface / January 2010

[3] IEEE 802.16m-07/002r9, IEEE 802.16m System Requirement Document (SRD)/2009-09-24

[4] Fletcher, R., (1971): A Modified Marquardt Subroutine for Nonlinear Least Squares.

Rpt. AERE-R 6799, Harwell

u-tdoa toa positioning for ieee 802.16m (c80216m-10_0221)

Documents