This paper presents a data link control layer for wireless ATM networks. The issues of wireless ATM and the necessity of a special DLC layer to support ATM functionality over the air are given. The medium access scheme principles are proposed in the paper, along with the DLC architecture. The major components and their functionality are described. The interactions of the DLC layer with higher layer entities along with intra-DLC interactions are proposed. The content of this paper is based on work carried out within the ACTS project AC08S Magic WAND.

The effectiveness of the recursive retransmission control algorithm proposed by B. Hajek (Proc. Inf. Sci. and Syst., p.116-20, Mar. 1982) is examined in the presence of jamming. The spread-spectrum network subjected to jamming is assumed to have infinite user population, employing both forward-error control (FEC) and automatic repeat request (ARQ), and a fixed arrival rate of new packets. Although the composite traffic, consisting of new transmissions (NTxs) and retransmissions (RTxs), is not Poisson, it can be approximated as such. Details for the throughput and the stability of the system are given based on a local Poisson approximation. Stability conditions are given for different levels of user side information.>

Techniques for deriving the power spectral density (PSD) of certain digitally modulated signals that are more general and easier to use than other similar methods are developed. These techniques are especially well suited for deriving the PSD of signal-product waveforms with arbitrary modulating pulse shapes. This is done by decomposing the PSD expression into two factors, one depending solely on the underlying sequences and the other depending only on the pulse shapes. General formulas are derived and, for some cases, they are expressed in terms of the discrete Fourier transform of appropriately defined sequences and the Fourier transform of the modulating pulse shape. Applications where these expressions would be useful include bit and code synchronizers, delay-and-multiply-type of detectors, and spread-spectrum and code-division multiple-access systems, either at radio or at optical frequencies.< >

The authors develop approximate methods for performance evaluation of a general class of slotted Aloha-type random-access spread-spectrum networks. Approximation is used in three levels: the diffusion approximation of the process Q(t) (a variant of the number of backlogged users), the approximation of the random-access channel and the existing receivers by a single server with equivalent queue-size-dependent service rate, and the approximation of the state-dependent composite traffic distribution by a Gaussian random variable with equivalent mean and variance. Applications and comparisons with the precise solutions are given.>