The design and performance aspects of Canada's fiirst commercial 14/12 GHz ANIK C earth stations are reviewed, with particular reference to the satellite link degradations of the 90 Mbit/s digital message service. Following design considerations based on computer simulations, extensive test data are presented with respect to BER, jitter, and other performance characteristics of the ioop closed via an ANlK C satellite simulator (SS). An analysis of the effects of linear and nonlinear distortions is applied to the formulation of a model that provides insight into the practical quantitative assessment of field tolerance and maintenance limits and of tradeoffs for new digital transmission systems.

The problems of satellite charges with reduced G/T stations for different pre-assigned and demand-assigned modes of operation are considered. A mixed pre-assigned demand-assigned operation is assumed as a model, in which large standard stations use the demand-assigned system for their overflow traffic. Determination of the optimum percentage of overflow for each link and of the global satellite revenue and occupancy, in terms of a general traffic matrix, is carried out and then used in the specific case of the Atlantic satellites to establish demand-assignment and pre-assignment charges as a function of G/T, based on a cost per unit bandwidth criterion. The effects of various demand-assignment systems on the economic balance is also considered. Definitions and SymbolsThe following definitions of symbols and terms used in this paper may be considered specific to this field of work: FM = frequency modulation FDMA = frequency division multiple access PCM = pulse code modulation PSK = phase shift keying TDMA = time division multiple access A11(r) = traffic in erlangs from station i to station i during the hour r(this is a matrix) [The traffic in erlangs is defined as: sum of holding times of all calls in given period duration of period which is equal to the average number of calls simultaneously in progress or, in fact, the average number of calls initiated during the average holding time.] CPA = charge in dollars per day per pre-assigned circuit CDA = charge in dollars per hour of use of a demandassigned circuit N11 = a matrix defining the number of circuits from i toj Csi = space segment cost of the ith Earth station BN =B(N, A) = loss probability from a group of N (integer) outlets when offered a traffic of A erlangs (i.e., grade of service as given in Erlang's traffic theory) np = number of hours per day during which overflow occurs K = the ratio of charges between pre-assigned and demand-assigned circuits = CPA/CDA AP = volume ofA during peak or busy hours Cs = satellite daily revenue in dollars p = peak or busy hours a, PO = constants * = traffic involving large (standard) stations tc = traffic involving large stations but related to light-traffic links (t = t* + t,) F = "peak-spread capacity factor", expressing the capacity advantage obtained when a spread of peak hours exists a = equivalence factor (determined in text) dB/k = decibels per degree kelvin All other symbols not included above are derived from those in the text.