Analysis of CDMA capacity of multi-beam satellite under beam coding

In order to solve the problem that satellite communication can't meet a large number of users' access due to the rapid increase of the number of users in satellite communication, this paper proposes a multi-beam forming architecture with orthogonal code coding for beams, and deduces the relationship between the number of users and outage probability of CDMA system with power control error under this architecture. The simulation results show that the number of users that can be accommodated in a single beam cell of CDMA system under this architecture is affected by spread spectrum gain, threshold signal-to-noise ratio and variance of power control error, and the number of users that can be accommodated in a single beam will increase by about 1.2 times every time the spread spectrum gain is doubled. The spread spectrum gain is unchanged, and the increase of the number of users that can be accommodated in a single-beam cell is maintained at about 28% when the different SNR thresholds are reduced by 1db. When the variance of PCE increases from 3dB to 4dB, the number of users will decrease by 12%.