Search

This paper investigates the uplink performance of a high-capacity direct-sequence code-division multiple-access (DS-CDMA) wireless communication system, where numerous antennas are distributed in the area covered by the system. Following the description of the system, typical characteristics of the distributed-antenna DS-CDMA (DA/DS-CDMA) system are summarized, in comparison with conventional DS-CDMA systems that employ centralized base station (BS) antennas. Then, the bit error rate (BER) performance of the DA/DS-CDMA system without using power control is investigated when the low-complexity correlation and minimum mean square error (MMSE) detectors are employed and when composite transmission pass loss, lognormal shadowing slow fading, and Nakagami-m fast fading are considered. Our analytical and numerical results suggest that the DA/DS-CDMA system constitutes a high-power-efficiency wireless system. For the same set of system parameters, the DA/DS-CDMA system is capable of providing a much higher capacity than the conventional DS-CDMA system. The DA/DS-CDMA system can be free from power control. Furthermore, the hand-over in the DA/DS-CDMA system is also very simple. Index Terms--Code-division multiple access (CDMA), distributed antennas, large-scale fading, multiple input-multiple output (MIMO), multiuser detection (MUD), single-user detection (SUD), small-scale fading.

In this paper we investigate a turbo detection scheme designed for robust video transmission over an uncorrelated Rayleigh fading channel. We first introduce a novel block error-correcting code, referred to as an extrinsic information transfer (EXIT)-chart optimized block code (ECOBC), which benefits from soft decision decoding. The ECOBC exploits both the residual redundancy which manifests itself in terms of the non-uniform probability distribution of K-bit strings inherent in the video encoded bit-stream, as well as the intentional redundancy imposed by the ECOBC for mitigating the effects of transmission errors. As our first novel contribution, we address the design of ECOBCs by formulating the necessary and sufficient condition, which ensures that the EXIT function of the sof-tbit ECOBC decoder reaches the (1,1) point in the EXIT chart. Secondly, we propose a novel real-valued free-distance metric for characterizing the ECOBC's performance. Furthermore, the attainable performance and the computational complexity imposed by the ECOBC are investigated. The effects of the interleaver delay on the ECOBC's performance are also quantified. As an additional result, we demonstrate that at a fixed system bandwidth, the turbo detection scheme using the H.264 video codec with the error concealment tools disabled but amalgamated with the proposed ECOBC as well as an additional generalized low-density parity-check (GLDPC) code may lead to an approximately 2.5 dB signal-to-noise ratio gain in comparison to the benchmarker having the same total bit rate, which operated the H.264 scheme with the error concealment tools enabled hence resulting in a higher video rate and amalgamated with the same-rate GLDPC code, but dispensing with our novel ECOBC. Index Terms--Error resilient video compression, extrinsic information transfer charts (EXIT), EXIT-chart optimized block code, generalized low-density parity-check (GLDPC) codes, H.264 standard, softbit APP decoding.

Subspace-based blind and group-blind space-time (ST) multiuser detection (MUD) is invoked for a smart-antenna-aided generalized multicarrier direct-sequence code-division multiple-access (MC DS-CDMA) system communicating over a dispersive ST Rayleigh fading channel, where the channel estimates are attained by using subspace-based blind techniques. Smart antennas are employed to provide increased degrees of freedom and, hence, to improve both the attainable single-user performance and the multiuser capacity. Furthermore, two adaptive subspace-tracking algorithms, i.e., the Projection Approximation Subspace-Tracking deflation (PASTd) algorithm and the Noise-Averaged Hermitian--Jacobi Fast Subspace Tracking (NAHJ-FST) algorithm, are employed for the sake of reducing the computational complexity imposed by eigenvalue decomposition. When employing the NAHJ-FST algorithm, the group-blind MUD employing an antenna array having M = 2 elements exposed to uncorrelated fading achieved a 4.2-dB signal-to-noise-ratio (SNR) gain at a bit error rate (BER) of [10.sup.-4] compared with that employing a single antenna, which is an explicit benefit of its increased computational complexity. Index Terms--Blind multiuser detection, frequency-domain spreading, generalized MC-CDMA, group-blind multiuser detection, MUD, time-domain spreading.

We employ the Mellin transform to facilitate the bit error ratio (BER) analysis of a fast frequency hopping (FFH)-assisted, M-ary frequency-shift keying (MFSK) using product combining (PC) when the transmitted signal is subjected to both Rayleigh fading and partial-band noise jamming. Exploiting the fact that the Mellin transform of the product of independent random variables is the product of their Mellin transforms, we derive the probability density function (PDF) of the PC's output. The derivation of the PDF then allows the computation of the system's BER. It is shown that the Mellin transform substantially simplifies the analysis of the PC receiver and hence facilitates, for the first time, the analysis of the FFH-MFSK PC receiver for modulation orders of M > 2. Index Terms--Fast frequency hopping (FFH), Mellin transform, partial-band noise jamming (PBNJ), probability density function (PDF), product combining (PC), Rayleigh fading, residues.

In this letter a multiuser transmitter preprocessing (MUTP) approach is proposed for downlink wireless communications, such as in spatial-division multiple-access (SDMA) or direct-sequence code-division multiple-access (DS-CDMA) system. In the proposed MUTP the preprocessing matrix is obtained by constructing a subspace that is orthogonai to the interference subspace without relying on eigen-analysis. The proposed MUTP fully removes the downlink multiuser interference, resulting in the zero-forcing (ZF) solution. It is capable of achieving the same bit error rate (BER) performance as the conventional ZF-based MUTP (ZF-MUTP). Index Terms--Pre-filtering, preprocessing, zero-forcing, multiple-input multiple-output, space-division multiple-access, direct-sequence code-division multiple-access, orthogonal subspace.

A novel ant colony optimization (ACO)-based multiuser detector (MUD) is designed for the synchronous multifunctional antenna array (MFAA)-assisted multicarrier direct-sequence code-division multiple-access (MC DS-CDMA) uplink, which supports both receiver diversity and receiver beamforming. The ACO-based MUD aims to achieve a bit-error-rate performance approaching that of the optimum maximum-likelihood (ML) MUD, without carrying out an exhaustive search of the entire MC DS-CDMA search space constituted by all possible combinations of the received multiuser vectors. We will demonstrate that regardless of the number of the subcarriers or of the MFAA configuration, the system employing the proposed ACO-based MUD is capable of supporting 32 users with the aid of 31-chip Gold codes used as the T-domain spreading sequence without any significant performance degradation when compared to the single-user system. As a further benefit, the number of floating-point operations per second imposed by the proposed ACO-based MUD is a factor of [10.sup.8] lower than that of the ML MUD. We will also show that at a given increase of the complexity, the MFAA will allow the ACO-based MUD to achieve a higher signal-to-noise ratio gain than the single-input-single-output MC DS-CDMA system. Index Terms--Ant colony optimization (ACO), multicarrier direct-sequence code-division multiple access (MC DS-CDMA), multifunctional antenna array (MFAA), multiuser detector (MUD), near-maximum-likelihood detection (near-MLD), uplink (UL).

In this paper, the achievable performance of Reed-Solomon (RS)-coded slow-frequency-hopping assisted M-ary frequency-shift keying using various erasure-insertion (EI) schemes is investigated when communicating over uncorrelated Rayleigh fading channels in the presence of multitone jamming. Three different E1 schemes are considered, which are based on the output threshold test, on the ratio threshold test, and on the joint maximum output--ratio threshold test. The relevant statistics of these EI schemes are investigated mathematically, and based on these statistics, their performance is evaluated in the context of RS error-and-erasure decoding (EED). It is demonstrated that the system performance can be significantly improved by using EED, invoking the EI schemes considered. Index Terms--Error-and-erasure decoding (EED), maximum output-ratio threshold test (MO-RTT), output threshold test (OTT), ratio threshold test (RTT), slow frequency hopping (SFH), tone jamming (TJ).

A time-hopping multicarrier code-division multiple-access (TH/MC-CDMA) scheme is proposed and investigated. In the proposed TH/MC-CDMA, each information symbol is transmitted by a number of time-domain pulses with each time-domain pulse modulating a subcarrier. The transmitted information at the receiver is extracted from one of the, say, M possible time-slot positions, i.e., assuming that M-ary pulse-position modulation is employed. Specifically, in this paper, we concentrate on the scenarios such as system design, power spectral density (PSD) and single-user-based signal detection. The error performance of the TH/MC-CDMA system is investigated when each subcarrier signal experiences flat Nakagami-m fading in addition to additive white Gaussian noise. According to our analysis and results, it can be shown that the TH/MC-CDMA signal is capable of providing a near ideal PSD, which is flat over the system bandwidth available, while decreasing rapidly beyond that bandwidth. Explicitly, signals having this type of PSD are beneficial to both broadband and ultrawide-bandwidth communications. Furthermore, our results show that when optimum user address codes are employed, the single-user detector considered is near-far resistant, provided that the number of users supported by the system is lower than the number of subcarriers used for conveying an information symbol. Index Terms--Code-division multiple access (CDMA), frequency-time matrix, multicarrier (MC), multiuser detection, Nakagami fading channels, power spectral density (PSD), time-hopping (TH), ultrawide-bandwidth (UWB) radio.

In this paper, the authors will investigate the performance of a loosely synchronized (LS) code-based space-time spreading (STS) scheme in comparison to that of classic Walsh code and pseudonoise code-based STS when communicating over dispersive Nakagami-m multipath channels. Closed-form formulas are derived for characterizing the bit-error-rate performance as a function of the number of resolvable paths L and the number of users K. Our numerical results suggest that the employment of LS code-based STS scheme is beneficial in a low-user-load and low-dispersion channel scenario, where a near-single-user performance can be achieved without a multiuser detector. Index Terms--Code-division multiple access (CDMA), Gaussian approximation, interference-free window (IFW), large area synchronized (LAS) codes, loosely synchronized (LS) codes, Nakagami-m fading.

The novel family of redundant residue number system (RRNS) codes is studied. RRNS codes constitute maximum-minimum distance block codes, exhibiting identical distance properties to Reed-Solomon codes. Binary to RRNS symbol-mapping methods are proposed, in order to implement both systematic and non-systematic RRNS codes. Furthermore, the upper-bound performance of systematic RRNS codes is investigated, when maximum-likelihood (ML) soft decoding is invoked. The classic Chase algorithm achieving near-ML soft decoding is introduced for the first time for RRNS codes, in order to decrease the complexity of the ML soft decoding. Furthermore, the modified Chase algorithm is employed to accept soft inputs, as well as to provide soft outputs, assisting in the turbo decoding of RRNS codes by using the soft-input/soft-output Chase algorithm. Index Terms--Redundant residue number system (RRNS), residue number system (RNS), turbo detection.

A burst-by-burst (BbB) adaptive speech transceiver is proposed, which can drop its source coding rate and speech quality under transceiver control in order to invoke a more error resilient modem mode among less favorable channel conditions. The adaptive multirate (AMR) speech eodec is operated at bit rates of 4.75 and 10.2 kb/s and combined with source sensitivity-matched redundant residue number system (RRNSI based channel codes. BbB adaptive joint detection aided code division multiple access is used for supporting the dual rate speech codec. Both the objective and subjective speech quality assessments favored the proposed BbB adaptive transceiver. Index Terms--AMR voice codec, HSDPA, RNS, RRNS.

In this contribution, we study a reduced-complexity multiuser detection aided multicarrier direct-sequence code-division multipleaccess (MC DS-CDMA) scheme, which employs both time (T)-domain and frequency (F)-domain spreading. We investigate the achievable detection performance in the context of synchronous TF-domain spread MC DS-CDMA when communicating over an additive white Gaussian noise (AWGN) channel. Five detection schemes are investigated, which include the single-user correlation based detector, the joint TF-domain decorrelating multiuser detector (MUD), the joint TF-domain MMSE MUD, the separate TF-domain decorrelating/MMSE MUD, and the separate TF-domain MMSE/decorrelating MUD. Our simulation results show that the separate TF-domain MUD schemes are capable of achieving a similar bit error rate (BER) performance to that of the significantly more complex joint TF-domain MUD schemes. Index Terms--Code-division multiple-access (CDMA), decorrelating, frequency-domain spreading, joint detection, minimum mean square error (MMSE), multicarrier (MC), multiuser detection, separate detection, time-domain spreading.

In multicarrier code-division multiple-access (MC-CDMA), the total system bandwidth is divided into a number of subbands, where each subband may use direct-sequence (DS) spreading and each subband signal is transmitted using a subcarrier frequency. In this paper, we divide the symbol duration into a number of fractional subsymbol durations also referred to here as fractions, in a manner analogous to subbands in MC-CDMA systems. In the proposed MC-CDMA scheme, the data streams are spread at both the symbol-fraction level and at the chip level by the transmitter, and hence the proposed scheme is referred to as the fractionally spread MC-CDMA arrangement, or FS MCCDMA. Furthermore, the FS MC-CDMA signal is additionally spread in the frequency (F)-domain using a spreading code with the aid of a number of subcarriers. In comparison to conventional MC-CDMA schemes, which are suitable for communications over frequency-selective fading channels, our study demonstrates that the proposed FS MC-CDMA is capable of efficiently exploiting both the frequency-selective and the time-selective characteristics of wireless channels. Index Terms--Broadband communications, code-division multiple access (CDMA), fractionally spreading, frequency-domain spreading, multicarrier modulation, Nakagami fading, time-domain spreading.

A novel sequential estimation method is proposed for the initial synchronization of pseudonoise (PN) signals derived from m-sequences. This sequential estimation method is designed based on the principle of recursive soft-in/soft-out (SISO) decoding, and we refer to it as the recursive soft sequential estimation (RSSE) acquisition scheme. The RSSE acquisition scheme exhibits a complexity similar to that of a conventional m-sequence generator, which increases only linearly with the number of stages in the m-sequence generator. Our simulation results also show that the acquisition time of the proposed RSSE acquisition scheme is also linearly dependent on the number of stages in the m-sequence generator. Owing to the above properties, the employment of the proposed RSSE acquisition scheme is beneficial for the acquisition of long m-sequences. Index Terms--Acquisition, initial synchronization, maximum-likelihood (ML) estimation, m-sequence, pseudonoise (PN) signals, recursive decoding, sequential estimation, soft-in/soft-out (SISO) decoding, spread-spectrum signals.

In this contribution, adaptive rate transmissions are investigated in the context of direct-sequence code-division multiple-access (DS-CDMA) systems using variable spreading factors (VSFs). In the context of the recently established family of adaptive rate-transmission schemes, the transmission rate is typically adapted in response to the channel's fading-induced quality fluctuation. By contrast, in this contribution the transmission rate is adapted in response to the multiuser interference fluctuations encountered. We present the philosophy of the proposed adaptive rate-transmission scheme and analyze the effective throughput as well as the achievable bit error rate (BER) performance, when communicating over additive white Gaussian noise channels. Our study shows that by employing the proposed VSF-assisted adaptive rate-transmission scheme, the effective throughput may be in creased by up to 40%, when compared to that of DS-CDMA systems using constant spreading factors. This increased throughput is achieved without wasting power, without imposing extra interference upon other users, and without increasing the BER. Index Terms--Adaptive rate transmissions, code-division multiple access (CDMA), Markov chain, matched filter receiver, multiuser interference, throughput, variable spreading factors (VSFs).

In this letter, we extend our investigation of generalized multicarrier direct-sequence code-division multiple access by considering two additional types of chip waveforms, namely, the time-domain half-sine and raised-cosine chip waveforms, in addition to the rectangular chip waveform. A range of closed-form equations are provided for quantifying the effect of both the multipath interference and the multiuser interference, when using partially overlapping subcarriers. These closed-form formulas allow us to evaluate the bit-error rate performance of arbitrary code-division multiple access schemes using overlapping subbands with the aid of the standard Gaussian approximation. Index Terms--Code-division multiple access (CDMA), multicarrier, frequency-selective fading.

A novel signaling scheme is presented, where a set of orthogonal signals is transmitted in parallel. The signals are selected according to the so-called residue number system (RNS). Hence the system is essentially a multiple code parallel communication scheme using high modulation alphabets. It is demonstrated that the system's performance can be substantially improved by exploiting a number of advantageous properties of the RNS arithmetic. In Part I of this paper, we focus our attention on the system's description and on the associated background of the RNS arithmetic, as well as on the performance evaluation of the residue number system arithmetic, using both nonredundant and redundant moduli based orthogonal signaling schemes, over an additive white Gaussian noise (AWGN) channel. Redundant RNS codes are introduced in order to protect the transmitted information. The detection techniques used in this novel system are different from conventional detectors. Specifically, a novel decision algorithm, referred to as a ratio statistic test, is designed, which implies dropping some of the lowest reliability demodulation outputs before the residue digits are transformed back to binary symbols. This improves the system's performance. This dropping technique is different from the conventional 'errors and erasures' decoding, where the erased symbols (or bits) should be computed and filled during decoding. We argue that the demodulated/decoded information can be obtained by decoding the retained or undiscarded symbols upon exploiting the properties of the RNS arithmetic. Our numerical results show that the proposed scheme constitutes a high-efficiency parallel transmission method for high-bit-rate communication, achieving a coding gain of 2 dB at a bit error rate of [10.sup.-6] over AWGN channels. Index Terms--Code-division multiple access (CDMA), error control, orthogonal signalling, parallel signalling, ratio statistic test, redundant residue number system (RRNS), residue number system (RNS).

A novel signaling scheme is presented, where a set of orthogonal signals is transmitted in parallel. The signals are selected according to the so-called residue number system (RNS). Hence the system is essentially a multiple code parallel communication scheme using high-modulation alphabets. It is demonstrated that the system performance can be substantially improved by exploiting a number of advantageous properties of the RNS arithmetic. The model treated in Part I of this paper is extended here to account for the effects of the multipath Rayleigh fading channel when using noncoherent demodulation. Diversity reception techniques with equal gain combining (EGC) or selection combining (SC) are concerned. The related performance is evaluated for both nonredundant and redundant RNS-based orthogonal signaling. Interleaving and forward error-correction techniques are introduced for enhancing the system's bit error rate (BER) performance. The concept of concatenated coding with a Reed-Solomon (RS) code as the outer code and a redundant RNS code as the inner code is presented, and the performance of the proposed concatenated code is evaluated. Expressions of the error probability for the above-mentioned scenarios are presented, and the associated BER performance is evaluated numerically with respect to specific system parameters. Without concatenated coding, coding gains up to 8.5 or 11 dB are achieved at a BER of [10.sup.-6] using the lowest reliability dropping technique of Part I and one or two redundant moduli, respectively. The BER is substantially higher than that over the additive white Gaussian noise channel reported in Part I. With the aid of RS coding, an additional 7.5-dB coding gain is achieved. Index Terms--Code-division multiple access (CDMA), concatenated coding, forward error correction, joint demodulation/decoding, M-ary orthogonal signaling, redundant residue number system (RRNS), residue number system (RNS).

A class of generalized multicarrier direct sequence code-division multiple-access (MC DS-CDMA) schemes is defined and its performance is considered over multipath Nakagami-m fading channels. The spacing between two adjacent subcarriers of the generalized MC DS-CDMA is a variable, allowing us to gain insight into the effects of the spacing on the bit error rate (BER) performance of MC DS-CDMA systems. This generalized MC DS-CDMA scheme includes the subclasses of multitone DS-CDMA and orthogonal MC DS-CDMA as special cases. We present a unified analytical framework for determining the exact average BER of the generalized MC DS-CDMA system over generalized multipath Nakagami-m fading channels. The optimum spacing of the MC DS-CDMA system required for achieving the minimum BER is investigated and the BER performance of the system having optimum spacing is evaluated. The resultant BER is compared with that of both multitone DS-CDMA and orthogonal MC DS-CDMA.

In this paper we propose two novel low-complexity, low-delay erasure insertion schemes, namely, the output threshold test (OTT) and joint maximum output and ratio threshold Test (MO-RTT). The employment of the OTT and MO-RTT is beneficial in the context of the "errors-and-erasures" Reed-Solomon (RS) decoding in a slow frequency-hopping spread-spectrum (SFH/SS) system using M-ary frequency-shift keying (MFSK). The statistics of the erasure insertion related decision variables associated with the OTT, MO-RTT as well as with the ratio threshold test (RTT) are investigated, when the channel of each frequency-hopping (FH) slot is modeled as flat Nakagami-m fading. The transmitted signals also experience both additive white Gaussian noise (AWGN) as well as partial-band Gaussian interference (PBGI). The properties of these erasure insertion schemes are investigated with the aid of their statistics. The performance of the proposed erasure insertion schemes and that of the erasure insertion scheme using the RTT is investigated and compared in the context of RS coded SFH/SS systems using MFSK. Furthermore, the performance of the RS coded SFH/SS systems is also compared both with and without side-information concerning the PBGI. Index Terms--Errors-and-erasures decoding, frequency-hopping, joint maximum output and ratio threshold test, M-ary frequency-shift keying, Nakagami fading, output threshold test, partial band interference, ratio threshold test, Reed-Solomon codes, spread-spectrum communications.

This paper compares the mean acquisition time (MAT) performance of two serial search acquisition schemes over frequency-selective multipath Rayleigh fading channels. Both the conventional cell-by-cell detection and the novel joint two-cell detection are characterized. In contrast to the majority of published results considering only one correct timing state ([H.sub.1] cell) in the certainty region of the pseudonoise (PN) sequence, this paper analyzes the MAT performance of the serial search acquisition schemes with multiple timing states in the uncertainty region. The MAT performance comparison between the conventional cell-by-cell detection and the joint two-cell detection shows that the latter can achieve an improved acquisition performance at almost the same complexity. Index Terms--Acquisition, direct-sequence code-division multiple-access, mean acquisition time, multipath fading channel, pseudonoise.

A novel multiple-access scheme based on slow frequency-hopping multicarrier direct-sequence, code-division multiple access (SFH/MC DS-CDMA) is proposed and investigated, which can be rendered compatible with the existing second-generation narrow-band CDMA and third-generation wide-band CDMA systems. Blind joint soft-detection of the SFH/MC DS-CDMA signals is investigated, assuming that the receiver has no knowledge of the associated frequency-hopping (FH) patterns invoked. The system's performance is evaluated over the range of Nakagami multipath fading channels. The results show that blind joint soft-detection achieves the required bit-error rate performance, while blindly acquiring the FH patterns employed. This is advantageous during the commencement of communications or during soft handover. Index Terms--Blind detection, code-division multiple access, constant-weight codes, frequency-hopping, orthogonal frequency-division multiplexing.

In this paper, a multiple-access spread-spectrum communication system using binary frequency shift keying (BFSK) or M-ary frequency shift keying (MFSK) and noncoherent demodulation is considered. In contrast to previous work typically assuming that the frequency shift keying (FSK) tones are nonoverlapping after direct-sequence (DS) spreading, here we consider a spread-spectrum multiple-access (SSMA) system under the assumption that the DS spread signals of different FSK tones are only orthogonal over the information symbol duration. Consequently, the frequency band of a spread FSK tone may be fully or partially overlapping with the other spread signals. An estimate of the variance of the multiple-access interference is obtained by assuming that the phase angles and time delays of the received signals are mutually independent random variables, provided that random signature sequences are employed for spreading. On the basis of the above assumptions, the bit error rate (BER) of our DS spread-spectrum multiple-access (DS-SSMA) and that of our hybrid DS slow frequency-hopping spread-spectrum multiple-access (DS-SFH SSMA) systems using FSK modulation is analyzed, when the channel impairments are constituted by a combination of additive white Gaussian noise (AWGN) and multiple-access interference. From our analysis and the numerical results, we concluded that, for a given system bandwidth and for a certain value of M, the system's BER performance can be optimized by controlling the amount of overlapping and that the systems with optimized overlapping outperformed the systems using no overlapping. Index Terms--Frequency shift keying (FSK), slow frequency hopping, spread-spectrum multiple access.

A class of generalized multicarrier direct sequence code-division multiple-access (MC DS-CDMA) schemes is defined and its performance is considered over multipath Nakagami-m fading channels. The spacing between two adjacent subcarriers of the generalized MC DS-CDMA is a variable, allowing us to gain insight into the effects of the spacing on the bit error rate (BER) performance of MC DS-CDMA systems. This generalized MC DS-CDMA scheme includes the subclasses of multitone DS-CDMA and orthogonal MC DS-CDMA as special cases. We present a unified analytical framework for determining the exact average BER of the generalized MC DS-CDMA system over generalized multipath Nakagami-m fading channels. The optimum spacing of the MC DS-CDMA system required for achieving the minimum BER is investigated and the BER performance of the System having optimum spacing is evaluated. The resultant BER is compared with that of both multitone DS-CDMA and orthogonal MC DS-CDMA.

In this paper we propose two novel low-complexity, low-delay erasure insertion schemes, namely the output threshold test (OTT) and joint maximum output and ratio threshold test (MO-RTT). The employment of the OTT and the MO-RTT is beneficial in the context of the errors-and-erasures' Reed--Solomon (RS) decoding in a slow frequencyhopping spread-spectrum (SFG/SS) system using M-ary frequency-shift keying (MFSK). The statistics of the erasure insertion related decision variables associated with the OTT, MO-RTT as well as with the ratio threshold test (RTT) are investigated, when the channel of each frequency-hopping (FH) slot is modeled as flat Nakagami-m fading. The transmitted signals also experience both additive white gaussian noise (AWGN) as well as partial-band Gaussian interference (PBGH). The properties of these erasure insertion schemes are investigated with the aid of their statistics. The performance of the proposed erasure insertion schemes and that of the erasure insertion scheme using the RTT is investigated and compared in the context of RS coded SFH/SS systems using MFSK. Furthermore, the performance of the RS coded SFH/SS systems is also compared both with and without side-information concerning the PBGI.