Method and system for enhancing channel capacity in a point to multipoint radio communications system having different kinds of terminals
View Patent ↗Method and system for enhancing channel capacity in a Point-to Multipoint radio communications system that includes terminal stations ( 12 ) of different kinds, such as residential terminals and business terminals, with different link budget requirements i.e. different signal-to-noise ratio. The method is characterized by the selective use of different channel coding codes such as forward error correction (FEC) codes, in the different concurrent channels, depending on a pre-defined category of an addressed subscriber. The multiplexing method used may be CDMA (Code Division Multiple Access) and TDMA (Time Division Multiple Access). Each terminal station ( 12 ) is in turn equipped only with an appropriate decoder, depending on its kind, e.g. residential or business.
1. Method for enhancing channel capacity in a point to multipoint radio communications system comprising at least a base station ( 11 ; 21 ) and a plurality of terminal stations ( 12 ) where said terminal stations present different requirements in relation to applications of radio digital channels, characterized in that the method comprises the steps of:
determining a radio resource consumption factor of a terminal station ( 12 ; 26 ; 28 ) according to said application requirements;
selecting a forward error correction code for coding a channel to be transmitted to a terminal station ( 12 ; 26 ; 28 ), said code being selected so as to optimize said radio resource consumption factor of said terminal station ( 12 ; 26 ; 28 );
using said forward error correction code for coding said channel; and
multiplexing concurrent channels having different forward error correction codings for transmission thereof.
2. Method according to claim 1 , wherein said radio resource consumption factor is determined as a function of a quality of service as well as of a link budget in the connection.
3. Method according to claim 1 , wherein the selection of said forward error correction code is made dynamically from among a set of pre-defined configurations, according to an instantaneous link budget of said terminal with the base station.
4. Method according to claim 1 , wherein the multiplexing is performed using code division multiple access (CDMA) technique.
5. Method according to claim 1 , wherein the multiplexing is performed using code division multiple access (CDMA) and time division multiple access (TDMA) techniques simultaneously.
6. System for enhancing channel capacity in a point to multipoint radio communications system comprising at least a base station ( 11 ; 21 ) and a plurality of terminal stations ( 12 ; 26 ; 28 ) where said terminal stations present different requirements in relation to applications of radio digital channels, characterized in that the system comprises:
means for determining a radio resource consumption factor of a terminal station ( 12 ; 26 ; 28 ) according to said application requirements;
coding means ( 11 ; 21 ) for coding a channel to be transmitted to a terminal station ( 12 ; 26 ; 28 ) according to a forward error correction code, said code being selected so as to optimize said radio resource consumption factor of said terminal station ( 12 ; 26 ; 28 );
means ( 11 ; 21 ) for multiplexing concurrent channels having different forward error correction codings for transmission thereof.
7. System according to claim 6 wherein each terminal station is equipped with a decoder suitable for decoding a forward error correction coding selected so as to optimize the radio resource consumption factor of said terminal station ( 12 ; 26 ; 28 ).
8. System according to claim 7 wherein the decoder is parametrized for all the configurations needed.
9. System according to claim 6 wherein said means for coding a channel is included in a base station.