1. Presented at ICAO ACP WGC Meeting,
FCS Technology Assessment Team: Technology Assessment Phase II – P34 Overview
Presented at ICAO ACP WGC Meeting,
Brussels, Belgium
September 21, 2006
Prepared by:
ITT/Glen Dyer
NASA/James Budinger

2. Public Safety Radio Systems
Standardized systems with open interfaces
APCO Standards
Developed by TR-8 Private Radio Technical Standards Committee, under sponsorship of the TIA in accord with a memorandum of understanding between TIA and APCO/NASTD/FED (Association of Public Safely Communications Officials/National Association of State Telecommunications Directors/Federal Government).
TETRA Standards
Produced by the Project Terrestrial Trunked Radio (TETRA) Technical Body of the European Telecommunications Standards Institute (ETSI)
TETRAPOL
Development of the publicly available specifications for TETRAPOL has been carried out by the manufacturers of the TETRAPOL Forum and the TETRAPOL Users’ Club
IDRA
Standardized by the Association of Radio Industries and Businesses (ARIB). The first version of Japan's digital dispatch standard, called RCR STD-32, was completed in March 1993. An updated version of this standard which did not alter the basic RF characteristics of the standard, but which did add substantial networking capability to the system, was approved in November 1995, and is referred to as RCR STD-32A.
Commercial spectrally efficient land mobile radio systems
Integrated Digital Enhanced Network (iDEN™) (referred to internationally as DIMRS) – Proprietary Motorola narrow-band TDMA voice and data system
EDACS (Enhanced Digital Access Communications System) – Proprietary Ericsson trunked narrow-band fail-soft system for critical communications

3. Public Safety Radio Standards Segmentation
Project Mesa
Bit Rate
APCO 34
Tetra Release 2 (TAPS, TEDS)
1000’s kbps
Broadband
100’s kbps
Wideband
10’s kbps
Narrow band
Channel Widths
6.25 kHz
25 kHz
50 kHz
200 kHz
25 MHz
APCO P25 Phase 1, 2
Tetra Release 1
TETRAPOL
IDRA
iDEN
EDACS
Chart courtesy of EADS Defense and Communications Systems, as provided in correspondence between ITT and EADS

4. Evolution of Public Safety Radio Standards
Pre-standard Analog, 25 kHz FM
European Standards Evolution
Pre-standard Analog FM Systems
Narrowband
Tetra Release I
25 kHz 4-slot TDMA
UHF Band
Wideband
Tetra Release II
TAPS – E-GPRS Overlay Network
TEDS – MCM, TDMA, Adaptive Modulation, 150 kHz
Solution
Space*
US Standards Evolution
APCO Project 16 Study
APCO Project 34
OFDM 150 kHz Channels
700 MHz Band
APCO Project 25 Phase I
12.5 kHz Digital
VHF and UHF Bands
APCO Project 25 Phase II 12.5 kHz TDMA
*Solution space - The set of technologies for constructing a public safety network.
Broadband
Project Mesa
50 MHz channel at 4.9 GHz
(Joint ETSI and EIA/TIA Standard)

5. P34 Overview
APCO Project 34 is a EIA/TIA standardized system for provision of packet data services in an interoperable dispatch oriented topology for public safety service providers
Standards available here:
Example standard description
TIA-902.BAAB - Complete Document Revision: A    Chg:    Date: 09/23/03   WIDEBAND AIR INTERFACE SCALABLE ADAPTIVE MODULATION (SAM) PHYSICALLAYER SPECIFICATION - PUBLIC SAFETY WIDEBAND DATA STANDARDS PROJECT - DIGITAL RADIO TECHNICAL STANDARDS
Project 34 concept is a government/commercial partnership
Provides universal access to all subscribers
Carefully controlled and managed network
Was developed to address “issues that restrict the use of commercial services for mission critical public safety wireless applications”
Priority access and system restoration
Reliability
Ubiquitous coverage
Security

6. P34 Overview (2)
A P34 network (called a “Wideband System”) can interoperate with other P34 networks (the ISSI standardized interface) with end-systems (Ew interface) and with mobile users over the air interface (Uw)
The air interface has defined modes between mobiles (MR to MR); between mobiles and fixed infrastructure (MR to FNE) and repeated modes for extending range to distant stations
Mobile Radios can serve as repeaters to extend range from FNE to distant Mobile Radios
The protocol stack is layered, and assumes a point of attachment to an IP network

7. P34 Overview (3)
P34 systems (shown as TIA-902 in the figure) are slated to be deployed using Frequency Division Duplexing with
Forward Link (Fixed Network Equipment, FNE, to Mobile Radios, MRC) between 767 and 773 MHz as shown in the figure
Reverse Link (MRC to FNE) between 797 and 803 MHz
The band could be cleared in some areas by December 31, 2006
Provided at least 85% of households have digital capable TV sets
Most likely date is (hard requirement) January 2009

8. Wideband (P34) Data Standards Status

9. P34 Air Interface (PHY) Description
There are two air interfaces (PHY) defined
SAM for interoperability
Has random access burst structure that incorporates 625 s propagation guard time (187.5 km) and s ramp-down (not included in guard)
VDL 3 guard time includes the ramp-down time and is 1.14 ms (334 km)
Random access burst structure rules could be modified to significantly increase system range
IOTA to provide additional data capacity
Has random access burst structure that incorporates 500 s propagation guard time (150.0 km) and 500 s ramp-down
MAC uses timing advance to offset mobile propagation delays
From the standard: “A timing advance feature managed by the MAC layer assumes that propagation delays are not seen at the radio receiver level except for initial random access slot”

10. Air Interface Specifics
Both Air Interfaces use a form of Multi-Carrier Modulation (Orthogonal Frequency Division Multiplexing, OFDM)
Frequency Domain Extensibility
Base channel is 50 kHz, with extensions defined to 100 kHz and 150 kHz
Each 50 kHz segment is comprised of 8 subcarriers (that map to defined subchannels)
Concatenate subchannel sync/pilot/data structure of the 50 kHz slot two, three times
Simplifies receiver design
Completely scalable to much larger bandwidths (if needed)
Each 50 kHz provides 96 to 288 kbps (modulation adapts with Eb/No)

11. Scaleable Adaptive Modulation Parameters
50 kHz Channel Configuration
100 kHz Channel Configuration
150 kHz Channel Configuration
RF Subchannels 8 16 24
Subchannel Spacing
5.4 kHz
Symbol Rate
4.8 k
Symbol Filter
Root Raised Cosine
( = 0.2)
Modulation Type 1
QPSK
(2 bits/symbol)
Modulation Type 2
16QAM
(4 bits/symbol)
Modulation Type 3
64QAM
(6 bits/symbol)
Modulation Rate 1
76.8 kbps
153.6 kbps
230.4 kbps
Modulation Rate 2
307.2 kbps
460.8 kbps
Modulation Rate 3
691.2 kbps
Demodulation
Coherent (Pilot Symbol Assisted)
TDM Slot Time
10 ms
Slot Interleave
Variable

12. Inbound Random Access Frame Structure

13. P34 Air Interface Interactions
IP Bearer Service Access Point
IP Bearer Service Access Point
IPv4
IPv6
IPv4
IPv6
Layer 3
Subnetwork Dependent
Convergence Protocol
(SNDCP)
Subnetwork Dependent
Convergence Protocol
(SNDCP)
Layer 3
PDP context activation, LLC UP setup, data transfer
PDS MM
PDS MM
CP functions: acknowledgement, retransmission, optional enhanced error detection
UP functions: Segmentation/Reassembly, acknowledgments, selective retransmission, enhanced error detection, flow control, windowing, buffering
Logical Link Control
(LLC)
Logical Link Control
(LLC)
Radio Link Adaptation
(RLA)
Radio Link Adaptation
(RLA)
Layer 2
Dynamic selection of modulation, channel coding, logical channel multiplexing configuration
Layer 2
Media Access Control
(MAC)
Synchronization, scrambling, link management, random access procedure, MAC address allocation, radio resource allocation, power control
Media Access Control
(MAC)
PHY
PHY
Layer 1
Layer 1

14. SNDCP Context Activation Sequence Diagram

15. UP Acknowledged Data Transmission Sequence Diagram

16. Overview of P34 Modeling P34 Analysis conducted
OPNET Modeling – the P34 protocol stack was modeled using OPNET Modeler
High fidelity simulation of protocol stack provided insight into technology performance
Offered load and scenario as specified in COCR for NAS “Super Sector”
Physical Layer Modeling – P34 physical layer was modeled with high fidelity by developing a custom C code application
Provided insight into technology performance in aviation environment
For performance assessment, C was chosen over SPW and MATLAB Simulink® due to complexity of P34 pilot structure
Interference Modeling – a model of the P34 transmitter was developed using SPW to assess P34 interference to UAT and Mode‑S Receivers
DME receiver modeling was undertaken, but was eventually terminated due to lack of “as built” algorithm information and insufficient fidelity with predictions to known results