The P25net Radio System

Transcription

1 The P25net Radio System Kevin Ball P25net Lead Engineer Kent Reeves Regional Sales Mgr Page 1 Copyright 2008 Raytheon Company. All rights reserved. Customer Success Is Our Mission is a trademark of Raytheon Company.

2 Raytheon Who is Raytheon? We are A technology leader specializing in defense, homeland security/public safety and other government markets throughout the world Sales: $24.9 Billion More than 72,000 employees worldwide Headquarters: Waltham, Massachusetts Web site: Page 2 Global leader in technology and innovation for 85 years

3 Our Civil Communications Strategy In order to deliver on our commitment to public safety, we focus on combining and successfully integrating the three essential elements of any operation: Technology People Solutions A proven strategy for success Page 3

4 An innovative, three-pronged approach Technology Standards-based open architecture that eases systems integration and future enhancements A broad range of best-fit technical solutions that are robust and scaleable Vendor neutrality enables use of best of breed solutions People Gain a deep understanding of each customer s requirements and environment Partner effectively with our customers today and into the future Solutions Leverage existing investments where possible Understand day-to-day and peak operating activities Innovative solutions for our customers Page 4

5 P25net System Architecture Overview

6 Raytheon P25net Radio System Benefits APCO P25 fully compliant without compromise P25 Common Air Interface Integral ISSI Architectural freedom Distributed, All IP network solution Seamless interoperability All-IP core network softswitch Single site & multi-site Conventional, trunked & mixed solutions Single or Mixed frequency bands Multi-Agency Support Composite channel trunking Scalable upgrade of existing systems Page 6

7 P25net TM Architecture RFSS Network Controller (RNC) CommTalk Console Key Management Facility IP Network Digital Voice Recorder To Other RFSS P25 ISSI PSTN Gateway Base Site Controller (BSC) P25 Digital Repeater Page 7 Network Management System (NMS)

8 Three Key Components RFSS Network Controller (RNC) Performs call management, call routing, mobility management and provides ISSI/CSSI SW application running on Linux Industrial Server Base Station Controller (BSC) Performs fixed site RF resource configuration and management SW application running on Linux Industrial Server P25 Digital Repeater Combination of Raytheon s Channel Controller and leading manufacturer s analog repeater Operates as Phase I P25 digital repeaters Interfaces to BSC Softswitch Application on COTS Server Page 8

9 P25net Simulcast System P25net Simulcast Page 9

10 Simulcast SIMULtaneous broadcast Broadcast the same modulation on the same frequency from multiple transmitters at the same time All sites have the same # of channels All sites use the same frequencies Voting System Required Page 10

11 Simulcast Reasons for Use of Simulcast Minimize Need for Frequencies Spectrally efficient means to expand coverage area when uniform traffic loading is desired/expected Page 11

12 Simulcast Call CH 1-10 CH 1-10 CH 1-10 When someone makes a call, that call is rebroadcast to every site regardless of whether or not there is someone to listen to it Requires control hardware to synchronize the timing CH 1-10 CH 1-10 Page 12

13 Simulcast Provides Seamless City-Wide Coverage CH 1-10 CH 1-10 CH 1-10 Page 13

14 Raytheon P25net TM Simulcast System Network Management System CommTalk Console (x Positions) Simulcast BSC, Master, Voter, GPS Oscillator RNC Emergency Dispatch Site Simulcast Control Site ISSI Based Logging Recorder Site Simulcast Tx Rx Site #1 P25 Channel Controller Channel 1 Channel 2 Channel 3 Simulcast Tx Rx Site #4 P25 Channel Controller Channel 1 Channel 2 Channel 3 P25 Channel Controller Channel 1 Channel 2 Channel 3 P25 Channel Controller Channel 1 Channel 2 Channel 3 Page 14 Simulcast Tx Rx Site #2 Simulcast Tx Rx Site #3

15 Simulcast Control Point Equipment RNC (RFSS Network Controller) BSC (Base Site Controller) Simulcast Master (Software Application) Voter Function Application (VFA) GPS Timing Oscillator Network Equipment RNC BSC, Simulcast Master, Voter Function GPS Timing Oscillator Simulcast Control Site Page 15

16 Simulcast Site Equipment Base Station Repeaters P25CCs (P25 Channel Controllers) GPS Timing Oscillator Network Equipment P25CC Repeaters GPS Timing Oscillator Page 16

17 P25net TM Voting Capability Today Digital P25 Conventional Voting Analog Conventional Voting Mixed Mode Voting Future Digital P25 Trunked Voting Page 17

18 P25net TM Voting Architecture Page 18

19 P25net TM Voting Capability Voting is done packet by packet Digital voting uses BER (Bit Error Rate) Analog voting uses RSSI (Receive Signal Strength Indicator) Page 19

20 P25net TM Voting Capability Figure 1: Voting Function Basic Message Flow Page 20

21 Receiver Coverage Example R1 R4 R3 R2 SU1 SU3 SU2 Figure 2: Voting Function Receiver Coverage Example A simple example of the voting process is shown above, with SU1 transmitting a signal. Due to its proximity to the SU, the Receiver at R2 receives the best possible representation of that signal. The same signal with lesser quality, as indicated by higher BER values, may also be received by one or more Receivers at R1 and R3, but is discarded by the voting process due to its lower signal quality. As SU1 moves closer to R3, the signal received by the Receiver at R3 becomes the highest-quality signal and thus becomes the voted signal that is passed to the BSC. Page 21

22 P25net TM Voting - Specifics Each instance of the voting function is typically configured to monitor and vote on all receivers that are currently operating at a single given frequency Number of discrete channels (from a frequency perspective) determines the number of voting functions necessary. Active Receiver First receiver to receive RF activity and forward the corresponding data becomes the active receiver. Is then used as a comparison reference for signals forwarded by other receivers. The active receiver is utilized until it no longer detects the RF receive signal. If the active receiver no longer detects the RF receive signal, another receiver is chosen as the active receiver. Page 22

23 P25net TM Voting Function Monitor Page 23

24 P25net Simulcast Testing P25net Simulcast system installed on Raleigh Live Lab System Page 24

25 P25net Live System in Raleigh Consists of three sites in the Raleigh area Camden Avenue Site Bethesda Site Raytheon Site Page 25

26 P25net Live System in Raleigh Three specific sets of tests were conducted Simulcast Transmit Testing Voter Function Testing Combined Simulcast/Voter Testing Page 26

27 P25net Live System in Raleigh Aeroflex 3920 P25 Test Set Generator Set for STD SPEECH Connected to Camden Ch 1 Rx to enable repeating of a recorded voice loop over the Simulcast channels Additional transmission of the P test pattern was used to aid in BER measurements Page 27

28 P25net Live System in Raleigh location between the sites where the signals met the criteria (RSSI>95dBm and BER=0 with RSSI difference less than 6dB) was chosen The location meeting the criteria was found approximately midway between the sites and designated as Pleasant and Horseshoe Roads Page 28

29 P25net Live System in Raleigh At this midpoint location, we measured RSSI and BER using the TAIT TP9155 Rx Diagnostics menu Table 1 RSSI RSSI BER Camden CH 1-77dBm 0% Bethesda CH1-79dBm 0% Page 29

30 P25net Live System in Raleigh Results Voice quality very good with no artifacts This would be expected as the delay midway between the sites would be approximately half the 33 usec maximum The Aeroflex stored speech loop proved very useful as it contains a number of random sentences by a variety of different accents in male and female voices. To determine the delay required for degraded voice quality, delays were introduced for each channel until distortion resulted. The results are shown in Table 2. Page 30

31 P25net Live System in Raleigh Table 2 Simulcast Delay vs. Voice Quality Simulcast Delay (microseconds) Result 30 Excellent voice quality 40 No change 50 Slight perceptible difference 60 No change from above 70 Some warble but no drop-outs 80 No change from above 90 No change from above 100 Severe distortion and break-up/drop-outs Page 31

32 What s Next? Simulcast Equipment is expected to be available in late September, early October timeframe. Release of new co-branded digital repeater expected in December/January timeframe. Page 32

33 P25net Simulcast Systems Questions? Page 33