Rectangular Constellation Research Articles

Wei-type trellis-coded modulation with 2N-dimensional rectangular constellation for N not a power of two

The Wei method of constructing trellis codes with 2N-dimensional rectangular signal constellations is limited to N being an integer power of two. In the present correspondence, this limitation is removed and examples of six-dimensional (6-D) and twelve-dimensional (12-D) trellis codes are given.

Letter: Opportunistic channel for sending an extra 300 bit/s using a trellis coded modulation scheme which transmits 9.6 kbit/s on telephone lines

AbstractIt is shown that the TCM scheme with 8‐D rectangular constellation designed by Tretter [1] based on a well known method invented by Wei [2] can support an opportunistic channel which can transmit 300 bits/s.

256‐state trellis code with 12‐D rectangular constellation using an extended wei method

AbstractThe Wei's method of constructing trellis codes with 2N‐D rectangular constellations is limited to N being an integer power of two. In the present letter to the editor, this limitation is removed and the example of a 256‐state, rate 4/5 linear trellis code with 12‐D rectangular signal set is given.

Performance of a rate-3/4 coded signal, incorporated with a circular signal set for regenerative satellite transmissions

The paper studies a digital modem that transmits a rate-3/4 convolutionally encoded 16-ary amplitude and phase modulated (CE16APM) signal, over a regenerative satellite link. The signal uses a (4, 12) circular signal constellation set and has a coding gain of about 4 dB at a bit error rate of 10-4, over an uncoded eight-phase-shift keyed (8PSK) signal. Several different earth stations are assumed to have simultaneous access to a given regenerative satellite using frequency division multiple access. Thus, the CE16APM signals that occupy the immediately adjacent frequency bands can introduce adjacent-channel interference (ACI) into the transmitted CE16APM signal. The high-power amplifier (HPA) at each of the earth-station transmitters or on board the satellite transmitter may introduce nonlinear AM-AM and AM-PM conversion effects into the CE16APM signal. Results of a series of computer-simulation tests are presented. These evaluate the effects of bandlimiting, nonlinear distortion and ACI on the performance of the modem. The HPA are tested with different values of output backoff (OBO). The performances of the preferred system arrangements are compared with those of a rate-3/4 convolutionally encoded 16-ary quadrature-amplitude-modulated (CE16Q AM) signal, using a rectangular signal constellation set, and of an uncoded 8PSK signal. It has shown that the CE16APM signal performs better than the CE16QAM and 8PSK signals over nonlinear channels.

Error probability of QASK with rectangular and circular symbol constellations in the presence of intersymbol quadrature channel and adjacent channel interference

Error probability of QASK with rectangular and circular symbol constellations in the presence of intersymbol quadrature channel and adjacent channel interference