In this paper, we study a multiple access scheme referred to as interleave-division multipleaccess (IDMA), in which interleavers are used as the only means for user separation. IDMA inherits many advantages from CDMA, such as diversity against fading and mitigation of the worst-case other-cell user interference problem. A low-cost iterative chip-by-chip multi-user detection algorithm is describ...

A noncoherent, bandwidth-efficient modulation scheme is proposed for frequency-hopping multiple-access (FH-MA) networks. The proposed scheme is a combination of noncoherent -ary amplitude-shift keying (NMASK) and orthogonal frequency-division multiplexing (OFDM). Using this scheme will minimize the required data bandwidth. The number of frequency slots available to the users will increase signi...

In this paper a new method to construct zero cross correlation code with the help of Pascal's triangle pattern called Pascal's Triangle Matrix Code (PTMC) for Spectral Amplitude Coding Optical Code Division Multiple Access (SAC-OCDMA) system is successfully developed. The advantages of this code are simplicity of code construction, flexibility of choosing code weight and number of users. The nu...

PART I of this special issue on signal processing for wireless communications, published in October 1998, contained 21 papers on diversity and antenna arrays, blind techniques, and orthogonal frequency division multiplexing (OFDM)-related techniques. In this issue, we present 22 papers on equalization and signal detection and multiuser detection and code division multiple access (CDMA)-related ...

The third generation partnership project (3GPP) Long Term Evolution (LTE) is the latest technology to tackle the increased need for mobile broadband services. Single-Carrier Frequency-Division Multiple Access (SC-FDMA) technology is being used for uplink (UL) transmission. In this system, the orthogonality between subcarriers is disrupted due to the presence of Carrier Frequency Offsets (CFOs) ...

We develop an expression for the minimum extra bandwidth needed for a frequency-division multiple-access (FDMA) system to outperform its code-division (CDMA) counterpart uniformly (that is, for all rate n-tuples) in a Gaussian multiple-access channel (MAC). For equalpower sources, the behavior of this factor is as an iterated logarithm of the number of users; hence it increases slowly yet is un...

It is well known that a Code Division Multiple Access (CDMA) scheme achieves higher user density in a cellular network with radio frequency signal in a terrestrial environment than either Time Division Multiple Access (TDMA) or (Frequency Division Multiple Access) FDMA could. The concept of a cellular (cluster) network has been introduced for underwater acoustic communications. However, its per...

Frequency hopped code-division multiple access (CDMA) is mostly used for wireless communication systems as it has the flexibility to provide a variety of services to many users under different propagation conditions. With limited spectrum, an FH-CDMA wireless communication system is interference limited. Interference avoidance and interference averaging can reduce the interference of the system...

The WiMAX forum is based on 802.16d/e Orthogonal Frequency Division Multiplexing (OFDM) based adaptive Physical Layer (PHY) layer. In this paper, the performance of WiMAX PHY layer is investigated for two PHY layer modifications, link adaption algorithm (Adaptive Modulation and coding, AMC) and MCCDMA (hybrid OFDM system with multiple access technology, Code Division Multiple Access) to provide...

Code Division Multiple Access (CDMA) technology allows a large number of mobile radio users to share limited bandwidth simultaneously. This is achieved by spreading individual users’ signals over available bandwidth with orthogonal spreading codes—the orthogonality of the spreading codes allows individual signals to be distinguished. The effective use of bandwidth in this system is a considerab...