Quick Paging
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number:
IEEE S802.16maint-08/139
Date Submitted:
2008-03-20
Source:
Havish Koorapaty, Per Ernstrom
Ericsson, Inc.
8001 Development Drive,
RTP, NC 27709
E-mail:
Voice:
+1 919 4727524
havish.koorapaty@ericsson.com
Venue:
Session #54 Maintenance Group
Base Contribution:
C802.16maint-08/139r4
Purpose:
Review and discuss in support for adoption of C802.16maint-08/139r4
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Introduction to Quick Paging
• Quick paging signal
– Mechanism to extend standby time of MS
– Used in CDMA2000 and WCDMA
• Indication to selected mobiles to read the full
paging message that occurs in a subsequent
frame.
– Absence of quick paging signal implies system
will not send a full page
• Significantly shorter duration of message
– Lowers the wake-up time of the MS
– Lowers the time the RF part of receiver is on
WiMAX Signal Structure
• Preamble, DL-MAP and data allocation need to be read
for paging message
• Preamble uses only every third subcarrier
• Quick Paging Signal could be used on other subcarriers
Effect on Legacy MS Preamble Reception of
Low Power Signal (20 dB below preamble)
Quick Paging Signal Design
• For 10 MHz, preamble has 568 empty spaces
– Use Walsh-Hadamard code of length 512: 512 codewords
• Orthogonal codes work well at low SNR
• Low complexity decoding method using the FWT
– Use a PN mask to avoid spectral peaks
• For 5MHz, length 256 Walsh-Hadamard code can be used
• Good channel estimates are available from the known
preamble
– Use bi-orthogonal code based on WH
• codewords and their inverses
• Number of addressable groups: 1024 for 10 MHz, 512 for 5
MHz
– Each group can be assigned a BWH codeword
– If received, then full paging message will be read
System Performance Evaluation
• Performance evaluation with System and Link Simulations
• Link and System Simulation methodology
–
–
–
–
600 uniformly distributed MS used
100 channel realizations per MS
100 codeword and noise realizations per channel realization
Get long-term path gain values for MS from different base stations
• Feed to link simulation
– Generate preamble and quick paging signal from each base station and
scale according to path loss
– Apply radio channel (Ped B)
– Generate additive noise
– Receive quick paging signal on own BS – practical channel estimation,
error covariance estimation
– Log error events
Performance Evaluation Parameters
Aspect
Value
Number of Cells/Sites
57/19
Reuse
1/1 (1/3 for preamble)
Path Loss Model
20 + 35 log(d) (similar to ITU Vehicular)
Site-to-Site Distance
2.8km
Penetration Loss
None
Shadowing Standard Deviation
8dB
Shadowing Correlation Distance
100m
Bandwidth
10 MHz
FFT Size
1024
Transmit Power (for Preamble)
20 W
Noise Figure
9 dB
Channel Model
Pedestrian B
Relative Power of Paging Signal
-20dB
Codeword Size
512
Performance Metrics
• Probability of Missed Detection (Pmiss)
– Codeword is sent, but MS misses receiving codeword
– Full Paging message is missed
• Probability of False Alarm (Pfalse)
– Different codeword is sent, but MS receiver mistakenly
identifies codeword as own
– MS will read full paging message
– System behavior is unaffected, but impact on MS battery
life
• Tradeoff between Pmiss and Pfalse with appropriate
thresholds
Performance Results
Energy Consumption Savings
• Assumptions:
– 250x57=14250 MS in paging area
– 512 paging groups
– Probability of an MS being paged, p = 1/1000
• Savings shown as a function of symbols currently needed
Text Modifications Summary
• Add quick paging as a supported feature in section “11.7.14.1
Mobility Features Supported”
• Add quick paging TLV to sections “6.3.2.3.26 DREG-CMD
(de/reregister command) message” and “6.3.2.3.40
MOB_SLP-RSP (sleep response) message”
• Add section 11.1.8.4 with TLV description for assigned
codewords
• Add quick paging parameters to DCD channel encodings
• Add text in MAC sections 6.3.21.1, 6.3.24 and 6.3.24.1
describing quick paging
• Add following PHY sections
– 8.4.6.1.1.3 defining sub-carriers used for quick paging
– 8.4.9.2.6 defining bi-orthogonal Hadamard encoding
– 8.4.9.4.3.3 defining quick paging modulation
Conclusions
• Design for quick paging signal in unused preamble space
• Negligible impact on existing functions involving preamble
• Performance evaluation shows reliable reception of quick
paging signal
• Significant energy savings with use of quick paging signal
• Functionality is applicable to Sleep and Idle modes in IEEE
802.16: text proposal provided