A method of implementing reliability enhanced transmission in radio repeater system
Original Publication Date: 2015-Jul-10
Included in the Prior Art Database: 2015-Jul-10
Chen, D.J.: INVENTOR [+6]
A real time procedure to detect transmitting SU in OOR utilized by both transmitting and receiving SUs which no need further communication of OOR status between the transmitting Scandidates to reduce the audio hole caused by selecting relay SU.U and the relay SU An automatic procedure to select the most appropriate relay SU in real time and the same procedure applies to the possible change of active relay SU without additional audio hole. A real time monitoring mechanism to revert the transmitting SU to normal repeater working mode once it moves back in range automatically.
By Chen Dajun, Fei Xun, Feng Wen, Gong Yahui, Tian Yong, Zhao Kangkai
In a radio repeater system, the subscriber has to be in the coverage range of a repeater site to be able to communicate with the system, as well as other subscribers. It is possible that a subscriber moves out from this range causing loss of the connection with the repeater system, which is called OOR. OOR may occur when subscriber is in either idle state or transmission state.
In Trunked system, due to constant communicating between subscriber and the system, the subscriber in idle state is able to detect OOR and give indication to user when user press PTT during OOR; however in a Conventional repeater system, subscriber has no way to know about the OOR thus no such indication when press PTT, which in turn causes the unreliable communication as user has no idea whether his/her voice is actually heard by the receivers.
Also in both Trunked and Conventional system, the unreliable communication could happen when the subscriber is already in transmission and becomes OOR during moving, where user keeps talking without being aware of loss communication with the system.
This paper discloses a method to enhance the reliability of transmission in repeater system that subscriber automatically transmits through repeater or relay channel when it is in range or out of range. It provides a real time procedure to detect transmitting SU in OOR utilized by both transmitting and receiving SUs which needs no further communication of OOR status between the transmitting SU and the relay SU candidates to reduce the audio hole caused by selecting relay SU. Selecting most appropriate relay subscriber according to RSSI/BER received on relay channel is conducted by all candidate receiving subscribers that applies to either the call initiator or relayer enters into out of range. It dynamically dismisses the relay channel when initiating subscriber returns to in range and both subscribers work back in normal repeater mode.
In current two-way radio repeater system, there is problem to make a reliable call that the transmitter and receivers can know the call is repeated constantly.
One typical scenario is that a subscriber in Conventional repeater system is OOR, while it still wants to PTT; the other scenario is that subscriber is already in transmission and becomes OOR due to movement, this scenario applies to both Trunked and Conventional system.
There are multiple detect methods utilizing different technologies such as RSSI indication, GPS location etc to help subscriber judge the status of OOR. Some of them just work when subscriber in idle or receiving mode; some of them are not accurate because of indirect detecting.
There are also multiple methods selecting the relay for subscriber in OOR. The general problems for these methods are:
§ Selection and maintenance of the rel...