Surety is performing system maintenance this weekend. Electronic date stamps on new Prior Art Database disclosures may be delayed.
Browse Prior Art Database

method of separate allocating inbound and outbound channel in trunking system

IP.com Disclosure Number: IPCOM000234093D
Original Publication Date: 2014-Jan-10
Included in the Prior Art Database: 2014-Jan-10
Document File: 5 page(s) / 1M

Publishing Venue


Related People

Chen, D.J.: INVENTOR [+5]


A method of asymmetrical dynamic channel assignment for Talk Group Calls in trunking system to increase frequencies utilization efficiency. TheTrunking system implemented this disclosure can assign different number of channels for inbound and outbound in the same talk group call among different sites involved in the Talk Group Call according to real time needs. For those sites having nobody speaking in the Talk Group call, only one outbound channel is assigned without inbound channel originally. The inbound channel can be assigned when one of the listeners want to speak. The inbound channel also can be released immediately once the talk is done. In this way the frequencies among different sites can be utilized more effective.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 39% of the total text.

Method of separately allocating inbound and outbound channels in a trunking system

By Chen Dajun, Zhao Kangkai, Yang Wu, Li Yong, Tian Yong

Motorola Solutions, Inc.



In a two way radio system, the inbound and outbound channels are assigned to a call in pairs for every involved site to guarantee bi-directional communication. Talk Group (TG) call is one of the major  types of calls. For every site where there is a member of an active TG call, a pair of inbound and outbound channels will be allocated. The typical scenario of TG call is one speaker with multiple listeners distributed among different sites. Given this fact, it is wasteful to allocate a pair of inbound and outbound channels for each site involved in the active TG call, since listeners are not utilizing the inbound channel.

This paper discloses a method to reduce the channel occupancy of a TG call by separately allocating inbound and outbound channels. For sites that only have listeners to a TG call, an outbound channel is assigned, but an inbound channel is not assigned until a speaker emerges in the site. In theory, for a TG call involving N sites, the channel occupancy savings is N-1. An inbound channel is allocated only on the requesting site where there is a user that wants to speak. It is released immediately once talking is ended while outbound channels enter into hang time. For a call requested from a console, no inbound channel is allocated. In this way the frequencies among different sites can be utilized more effectively.


In the current two-way radio wide-area trunking system, when a Talk Group Call is initiated, a pair of physical channels including one inbound and one outbound frequency will be assigned for every site involved in the Talk Group Call. Normally only one user talks regardless of how large the Talk Group is and how many sites are involved. This typical use case illustrates the waste of resources inherent in the current Talk Group channel assignment mechanism, which is that only one inbound channel in one site is in use while every receive-only site still reserves an inbound channel. A Talk Group call having N sites involved has N-1 inbound channels reserved unnecessarily until the end of the Talk Group call, which is not an efficient use of the channel frequencies. If the call is from a console it also allocates a pair of channels for inbound and outbound in any participating site, which is not an efficient way to utilize the channel frequencies since the inbound channel is not requested.



In a traditional trunking radio system, for each site, the outbound channel and inbound channel are always paired. When a group call request comes in, the zone controller checks all of the sites which have talk group members located in them to see if there is an inbound and outbound channel pair free for use. If there is an available channel pair in every participating site then the call is granted and an inbound and outbound channel pair is alloc...