Conventional vs Trunking Radio Systems AWIN NETWORK SUPPORT

Conventional vs. Trunking Radio Systems AWIN NETWORK SUPPORT BASIC LEVEL OVERVIEW

Table of Contents • What is Arkansas Wireless Information Network (AWIN)? • Trunking Radio Systems – Basic Overview • Trunking vs. Conventional Radio Systems • How Does Trunking Work? • Trunking Simulcast Technology • Digital vs. Analog Modulation Technology • What is P 25?

What is AWIN?

What is AWIN? • The statewide, multiple site, digital 700/800 MHz trunked communications system using the Association of Public Safety Communications Officials (APCO) Project 25 (P 25) standard. • AWIN provides a reliable, statewide means of communication for the state’s first responders. The AWIN system consists of over 100 tower sites and over 27, 000 authorized radios. • AWIN provides statewide operations, • AWIN is monitored 24/7/365 to within the coverage area of the system ensure that it is available whenever for public service entities using P 25 the first responder needs it. digital 700/800 MHz radios.

Trunking Radio Systems – Basic Overview Zone Controller Site Controller Channel 1 Control Channel 2 Alt. Control Channel 3 Channel 4 Channel 5

Trunking Radio Systems – Basic Overview What is Trunking? • Trunking is defined as: “The sharing of a limited number of communication paths (or Trunks) among many users” • Trunking is not a term that is owned or belongs to a specific vendor/manufacturer. • Trunking is not a term that is exclusive to radio systems.

Trunking vs. Conventional Radio Systems ? ? ?

Trunking vs. Conventional Radio Systems • Conventional Radio (repeater) System: • Uses a dedicated radio frequency for each radio channel in a system (unless sharing a channel) • A Channel = a Frequency (i. e. , 155. 555 MHz is County Sheriff, 156. 555 is County Fire) • Each frequency is assigned to a group of users.

Trunking vs. Conventional Radio Systems • Conventional Radio (base or repeater) System: • A Channel = A Frequency • If a channel is in use, the radio user must wait in “queue” before being able to transmit on the system. • A new frequency must be obtained each time another “channel” is needed in the radio system. • The system is limited by the number of frequencies in the system.

Trunking vs. Conventional Radio Systems • Trunked Radio (repeater) System: • Uses a group of similar radio frequencies to create a “pool” for radio system user to access. • Systems can by built using VHF, UHF, 700, or 800 MHz. (AWIN is 700/800) • A Channel is NOT a Frequency (generally speaking) • A Channel (on your radio) is now a computer generated code… • …referred to as a TALK GROUP

Trunking vs. Conventional Radio Systems • Trunked Radio (repeater) System: • The entire system is managed by a computer, on AWIN this is called the Zone Controller. One Zone Controller for the North ½ of the State and one Zone Controller for the South ½ of the State. • All radio in the system, also, are computer controlled, and communicate to the Zone Controller via one frequency know as the “Control Channel”.

Trunking vs. Conventional Radio Systems • Trunked Radio System Benefits: • Greatly improved usage of radio frequencies (can be quite scarce depending on frequency band) • Brings radio users together on a common radio system. • Consistency in radio coverage. • Greater over radio system flexibility, including: • Channel (Talk Group) capabilities. • Various user features, including Emergency Alarm, PTT ID, Channel Regrouping, Call Alert, and Radio Inhibit.

Trunking vs. Conventional Radio Systems • Talk Group Dragging ◦ Dragging is when a talk group is being used across the radio system and is not part of the incident/area they are listening in to. ◦ A trunked (AWIN) radio system can not tell when a radio is just listening – It assumes all affiliated radios are equally important and needs the recourses. ◦ This “just listening” will use up resources at each tower it crosses to get the message/PTT to you.

How Does Trunking Work? Control Channel continuously Transmits system data to all radios Channel 3 RX/TX Channel 2 Channel 1 Control Channel RX/TX Channel 4 RX/TX Alt. Control Channel RX/TX Channel 5 RX/TX Site Controller Zone Controller

How Does Trunking Work? Radio user presses TX button. The radio information is sent via the control channel To the site controller Channel 3 RX/TX Channel 2 Alt. Control Channel 1 Control Channel RX/TX Channel 4 RX/TX Channel 5 RX/TX Site Controller Zone Controller

How Does Trunking Work? The site controller processes the inbound request and sends the repeater channel command (in this case Channel 3) back to all radios selected on the same Talk Group Channel 3 RX/TX Channel 2 Channel 4 RX/TX Alt. Control Channel 1 Control Channel RX/TX Channel 5 RX/TX Site Controller Zone Controller

How Does Trunking Work? The original radio user’s radio automatically switches to The correct voice channel and begins transmitting; All radios selected on the same Talk Group do the same and hear the voice transmission Channel 3 RX/TX Channel 2 Channel 4 RX/TX Alt. Control Channel 1 Control Channel RX/TX Channel 5 RX/TX Site Controller Zone Controller

How Does Trunking Work? Radio System Fleet Mapping: Radio “Channels” are now Called “Talk Groups”. (Example Law Enforcement Shown Here) Radio Zone 1 2 Dispatch 1 TG ID# XXXXXX TG ALIAS MAC CALL TG ID# XXXXXX TG ALIAS Dispatch 2 TG ID# XXXXXX TG ALIAS MAC 1 TG ID# XXXXXX TG ALIAS CID TG ID# XXXXXX TG ALIAS MAC 2 TG ID# XXXXXX TG ALIAS ADMIN TG ID# XXXXXX TG ALIAS MAC 3 TG ID# XXXXXX TG ALIAS

? Questions…so far?

Trunking Simulcast Technology • Simulcast Transmitting • A radio system where the same radio frequencies are Simultaneously Broadcast from all tower sites within the radio system (That are grouped together). • This allows the same radio frequencies to be used throughout the entire coverage area.

Trunking Simulcast Technology • Simulcast Benefits • Seamless communications throughout the radio system’s coverage area • Improved radio frequency utilization • Improved coverage in areas with difficult terrain (includes tall buildings) • Improved in-building coverage (signals in overlap zones are “additive”)

Trunking Simulcast Technology • Simulcast Cons • The technology can be expensive • Tower site spacing in critical (especially when using NPSPAC frequencies) • Signal “timing” is critical between all sites • Tower site interconnection (via microwave, T 1, etc. ) is critical and can be expensive

Trunking Simulcast Technology Site 2 f 1 f 2 f 3 f 4 f 5 Simulcast Site 5 Site 1 f 2 f 3 f 4 f 5 f 1 f 2 f 3 f 4 f 5 Site 3

Trunking Simulcast Technology • Simulcast Issues • Amplitude and frequency of transmitted signals must be very accurately timed to ensure good signal quality.

Trunking Simulcast Technology • Simulcast Issues • Slightly out of phase – “Ghosting on a T. V. set • Out-of-phase signals can cause destructive cancellation. • Fully in-phase signals produce constructive composite signals

Digital vs. Analog Modulation Technology

Digital vs. Analog Modulation Technology • Analog vs. Digital • Digital is the newer format of the two • Newer 700/800 MHz are digital • What is the difference? • Is digital better, and why?

Digital vs. Analog Modulation Technology • Analog vs. Digital Analog Transmission Digital Transmission Information is sent by changing the frequency, amplitude, or phase of the radio signal. Information is converted to true data bits and applied directly to the radio transmitter using FDMA (or TDMA or CDMA)

Digital vs. Analog Modulation Technology • Digital Benefits • Clearer audio throughout system coverage area • Improved radio frequency efficiency • Improved system coverage • Imbedded signaling options • Encryption with little-to-no range loss

What is P 25? • P 25 • The standard for the manufacturing of interoperable digital 2 -way wireless communications products. • Also known as Project 25 or APCO 25. • A user driven standard, it is not industry or Federal Government Standard

What is P 25? • P 25 Equipment • Must demonstrate compliance • Meet the needs of public safety • Be Interoperable with other P 25 equipment

? ? Final Questions