Method and apparatus for layered modulation
First Claim
1. A method for simulating a layer modulated signal comprising the steps of:
- providing an upper layer signal comprising a first modulated bit stream;
providing a lower layer signal comprising a second modulated bit stream;
attenuating the lower layer signal; and
combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal;
wherein at least one directional coupler is used to tap the composite layer modulated signal.
1 Assignment
0 Petitions
Accused Products
Abstract
Improvements to a layered modulation (LM) implementation are disclosed. The present invention discloses two implementations of LM, using single and multiple transponders per signal frequency, respectively. Layered hierarchical 8PSK (H-8PSK) is a special case of LM. By re-encoding the high-priority (HP) portion of an H-8PSK signal, LM can improve carrier-to-noise ratio (CNR) of a H-8PSK signal. LM can be computer-simulated and a two-layered signal can be sequentially demodulated with a predicted CNR performance. An LM signal can be simulated 10 using live signals for off-line processing. In addition, a signal processing apparatus can process in real time LM signals emulated from live satellite signals.
-
Citations
29 Claims
-
1. A method for simulating a layer modulated signal comprising the steps of:
-
providing an upper layer signal comprising a first modulated bit stream;
providing a lower layer signal comprising a second modulated bit stream;
attenuating the lower layer signal; and
combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal;
wherein at least one directional coupler is used to tap the composite layer modulated signal. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. (canceled)
-
8. A signal simulator for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising:
-
a first modulator for modulating a bit stream of the upper layer to produce an upper layer signal;
a noise generator for adding noise to the upper layer signal;
a second modulator for modulating a bit stream of the lower layer to produce a lower layer signal;
an attenuator for attenuating the lower layer signal; and
a combiner for combining the noise-added upper layer signal and the attenuated lower layer signal to produce a composite layer modulated signal. - View Dependent Claims (9, 10, 11, 12)
-
-
13. A receiver system for simulating a layer modulated signal, comprising:
-
a first antenna for receiving an upper layer signal from a first satellite transponder;
a first amplifier for amplifying the received upper layer signal;
a second antenna for receiving a lower layer signal from a second satellite transponder;
a second amplifier for amplifying the received lower layer signal;
an attenuator for attenuating the received lower layer signal; and
a combiner for combining the upper layer signal and the attenuated lower layer signal to produce a composite layer modulated signal. - View Dependent Claims (14, 15)
-
-
16. A method for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising the steps of:
-
providing an upper layer signal comprising a first modulated bit stream;
providing a lower layer signal comprising a second modulated bit stream;
attenuating the lower layer signal; and
combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal;
tuning the composite layer modulated signal;
evaluating the composite layer modulated signal performance based upon the in-phase and quadrature components of the layer modulated signal. - View Dependent Claims (17, 18, 19, 20, 21)
-
-
22. A signal simulator for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising:
-
a first modulator for modulating a bit stream of the upper layer to produce an upper layer signal;
a noise generator for adding noise to the upper layer signal;
a second modulator for modulating a bit stream of a lower layer to produce a lower layer signal;
an attenuator for attenuating the lower layer signal;
a combiner for combining the noise-added upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal; and
a directional coupler, for tapping the composite layer modulated signal. - View Dependent Claims (23, 24, 25, 26)
-
-
27. A signal simulator for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising:
-
a first antenna for receiving the upper layer signal from a first satellite transponder;
a first amplifier for amplifying the received upper layer signal;
a second antenna for receiving the lower layer signal from a second satellite transponder;
a second amplifier for amplifying the received lower layer signal;
an attenuator for attenuating the received lower layer signal; and
a combiner for combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal. - View Dependent Claims (28, 29)
-
Specification