A slotted asynchronous (SA) code-division multiple-access communication scheme controlling the time of arrival is proposed for distributed spread-spectrum packet radio networks where the transmission range is limited as in an indoor wireless system. In this scheme, each terminal can send its packet randomly at any one of N/sub w/, possible time instants, equally spaced over one period of direct-sequence spread-spectrum signals. Such transmissions initiated at different time instants can be resolved because of the high time resolution of wide-band signals if the channel delays associated with multipath are small due to limited transmission range. Quasi-synchronous distributed networks are considered to allow timing drift among terminals and also reflect wireless multiple-access channels, in which common-transmitter-based (C-T) and receiver-transmitter-based (R-T) spreading code assignments are adopted to permit a contention mode only for the header portion. The throughput is evaluated under the spread ALOHA assumption on collision events and also by reflecting the effect of the MAI in the header detection process. Theoretical results show that the combination of the SA scheme with C-T assignment results in more significant improvement than the case of R-T assignment, and also the former provides the benefit of the efficient usage of spreading codes in a code-limited environment.
[1]
M. Pursley,et al.
Numerical Evaluation of Correlation Parameters for Optimal Phases of Binary Shift-Register Sequences
,
1979,
IEEE Trans. Commun..
[2]
Jr. Hall.
Combinatorial theory (2nd ed.)
,
1998
.
[3]
John A. Silvester,et al.
Spreading code protocols for distributed spread-spectrum packet radio networks
,
1988,
IEEE Trans. Commun..
[4]
M.B. Pursley.
The role of spread spectrum in packet radio networks
,
1987,
Proceedings of the IEEE.
[5]
N. Abramson,et al.
Multiple access in wireless digital networks
,
1994,
Proc. IEEE.
[6]
Dong In Kim,et al.
Random Assignment/Transmitter-Oriented Code Scheme for Centralized DS/SSMA Packet Radio Networks
,
1996,
IEEE J. Sel. Areas Commun..
[7]
Norman Abramson,et al.
The ALOHA System-Another Alternative for Computer Communications
,
1899
.
[8]
Dong In Kim,et al.
On the performance of centralized DS-SS packet radio networks with random spreading code assignment
,
1995,
IEEE Trans. Commun..
[9]
L. Kleinrock,et al.
Packet Switching in Radio Channels: Part I - Carrier Sense Multiple-Access Modes and Their Throughput-Delay Characteristics
,
1975,
IEEE Transactions on Communications.