  This paper examines the uplink transmission of a single-antenna handsheld
user to a cluster of satellites, with a focus on utilizing the inter-satellite
links to enable cooperative signal detection. Two cases are studied: one with
full CSI and the other with partial CSI between satellites. The two cases are
compared in terms of capacity, overhead, and bit error rate. Additionally, the
impact of channel estimation error is analyzed in both designs, and robust
detection techniques are proposed to handle channel uncertainty up to a certain
level. The performance of each case is demonstrated, and a comparison is made
with conventional satellite communication schemes where only one satellite can
connect to a user. The results of our study reveal that the proposed
constellation with a total of 3168 satellites in orbit can enable a capacity of
800 Mbits/sec through cooperation of $12$ satellites with and occupied
bandwidth of 500 MHz. In contrast, conventional satellite communication
approaches with the same system parameters yield a significantly lower capacity
of less than 150 Mbits/sec for the nearest satellite.
