Single Antenna Interference Cancellation
Encyclopedia
Single Antenna Interference Cancellation ("SAIC") is a promising technology to boost the capacity of GSM networks without any needed change in the network.
It is very much in the interest of the network operator to use the allocated spectrum as efficiently as possible and to the highest possible capacity because most of the investment is done to get the licence for it. It would be desirable to have the frequency reuse of one, which means that each cell can operate in the same frequency. This in turn creates interference
to the users operating in nearby places. Increase Interference causes voice quality to drop and may cause call drop. It is now a well known fact that it is possible to cancel the interference at the mobile handset side by changing the baseband software without changing anything in the network side. SAIC-enabled mobiles can work in high interference levels. SAIC-enabled mobiles need even less transmit power from the network which in turn reduces the interference in the network. Studies shows that the speech quality gain can be about 6% at a SAIC mobiles penetration of 10%, about 37% at a SAIC mobiles penetration of 50%, about 99% at a SAIC mobiles penetration of 100%.
It is very much in the interest of the network operator to use the allocated spectrum as efficiently as possible and to the highest possible capacity because most of the investment is done to get the licence for it. It would be desirable to have the frequency reuse of one, which means that each cell can operate in the same frequency. This in turn creates interference
Electromagnetic interference
Electromagnetic interference is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source. The disturbance may interrupt, obstruct, or otherwise degrade or limit the effective performance of the circuit...
to the users operating in nearby places. Increase Interference causes voice quality to drop and may cause call drop. It is now a well known fact that it is possible to cancel the interference at the mobile handset side by changing the baseband software without changing anything in the network side. SAIC-enabled mobiles can work in high interference levels. SAIC-enabled mobiles need even less transmit power from the network which in turn reduces the interference in the network. Studies shows that the speech quality gain can be about 6% at a SAIC mobiles penetration of 10%, about 37% at a SAIC mobiles penetration of 50%, about 99% at a SAIC mobiles penetration of 100%.
Approaches
There are various approaches possible to have a SAIC-enabled phone:- Prefilter based baseband algorithms (2X complex than conventional receiver but gives 12-15 dB gain)
- Constant Modulus based SAIC (simple but less gain and also it is not very robust)
- Joint Detection (JD)
- Best case (Training sequence and timing of Interferer is known)
- very high gain compared to all available algorithms
- not a practical method as without signaling message support from the network it is not possible to know the training sequence of the interferer
- Worst case (Training sequence and timing of interferer is not known)
- Very high complexity
- good gains in terms of dB
- not a practical method of implementation because of complexity
- Best case (Training sequence and timing of Interferer is known)