SIR-optimized weighted linear parallel interference canceller on fading channels

Tikiya, V.; Shamaiah, Manohar; Chockalingam, A.

doi:10.1109/twc.2006.1687711

Cited by 12 publications

(18 citation statements)

References 7 publications

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“…Alternately, the relay could use a linear PIC (LPIC) [7], [8] (which uses soft values of previous stage outputs in constructing the MAI estimates for cancellation in a given stage), and send the soft values of the (m − 1)-th stage output to the destination nodes in Phase-2. We assume that these soft values reach the destination nodes perfectly.…”

Section: Resultsmentioning

confidence: 99%

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A Distributed Approach to Interference Cancellation

Raghu

Mohammed

Chockalingam

2007

IEEE GLOBECOM 2007-2007 IEEE Global Telecommunications Conference

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Abstract-In this paper 1 , we propose and analyze a novel idea of performing interference cancellation (IC) in a distributed/cooperative manner, with a motivation to provide multiuser detection (MUD) benefit to nodes that have only a single user detection capability. In the proposed distributed interference cancellation (DIC) scheme, during Phase-1 of transmission, an MUD capable cooperating relay node estimates all the sender nodes' bits through multistage interference cancellation. These estimated bits are then sent by the relay node on orthogonal tones in Phase-2 of transmission. The destination nodes receive these bit estimates and use them for interference estimation/cancellation, thus achieving IC benefit in a distributed manner. For this DIC scheme, we analytically derive an exact expression for the bit error rate (BER) in a basic five-node network (two source-destination node pairs and a cooperating relay node) on AWGN channels. Analytical BER results are shown to match with simulation results. For more general system scenarios, including more than two source-destination pairs and fading channels without and with space-time coding, we present simulation results to establish the potential for improved performance in the proposed distributed approach to interference cancellation. We also present a linear version of the proposed DIC.

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Section: Resultsmentioning

confidence: 99%

“…, m ≥ 2, denote the kth user soft output at the (m − 1)th stage LPIC in the relay node during Phase 1, which is given by [7], [8] …”

Section: Resultsmentioning

confidence: 99%

A Distributed Approach to Interference Cancellation

Raghu

Mohammed

Chockalingam

2007

IEEE GLOBECOM 2007-2007 IEEE Global Telecommunications Conference

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“…Note that, since (14) is structurally the same as (9), and the [.] operation in (15) does not add to complexity, the proposed G p (m) filter has the same complexity as the G (m) filter.…”

Section: A Proposed Matrix Filtermentioning

confidence: 99%

“…where ρ jk = ρ kj is the normalized cross-correlation coefficient between the spreading waveforms of users j and k, given by ρ jk = k , in CLPIC is given by [9] …”

Section: Introductionmentioning

confidence: 99%

Improved Linear Parallel Interference Cancellers

Srikanth

ardhan

Chockalingam

et al. 2007

2007 IEEE International Conference on Communications

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Abstract-In this paper, taking the view that a linear parallel interference canceller (LPIC) can be seen as a linear matrix filter, we propose new linear matrix filters that can result in improved bit error performance compared to other LPICs in the literature. The motivation for the proposed filters arises from the possibility of avoiding the generation of certain interference and noise terms in a given stage that would have been present in a conventional LPIC (CLPIC). In the proposed filters, we achieve such avoidance of the generation of interference and noise terms in a given stage by simply making the diagonal elements of a certain matrix in that stage equal to zero. Hence, the proposed filters do not require additional complexity compared to the CLPIC, and they can allow achieving a certain error performance using fewer LPIC stages.

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“…PIC that uses the MF output at each stage to form a soft (linear) estimate of MAI is used for fading channel conditions and referred to here as 'conventional PIC' [2,6]. Recently weighted linear PIC for operation in Rayleigh fading channels is investigated in [9] to improve the signal-to-interference ratio (SIR) at each stage of the PIC. Optimum weight for IC for each user is derived using the knowledge of crosscorrelations of users' sequences for maximizing the average SIR.…”

Section: Introductionmentioning

confidence: 99%

Robust blind PIC with adaptive despreader and improved interference estimator

Shakya

Ali

Stipidis

2008

Int J Communication

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SUMMARYAn effective design of multistage parallel interference cancellation (PIC) receiver using blind adaptive (BA) despreader and pre-respreader interference estimator for uplink CDMA is proposed and analysed. A novel algorithm is designed, which exploits constant modulus (CM) property of the users' transmitted signals and inherent channel condition to perform adaptive despreading based on minimum error variance criteria. This is carried out by BA weighting of each chip signal for accurate tracking of the desired user's signal power and hence for more improved data detection at the output of each stage of PIC. Furthermore, the despreader weights are used within the adaptive pre-respreader interference estimation and cancellation to obtain online scaling factors during every symbol period, without any knowledge of users' channels or the use of training sequences. It is found that this way of estimation is optimal in minimum mean squared error sense, and hence, significant reduction in interference and noise variance is observed in detection and estimation of the desired users' signals compared with conventional PIC. Bit error probability of the proposed PIC is obtained using Gaussian Approximation method. Extensive simulation results are shown, which demonstrate impressive performance advantage in fading environments, high system loading, and severe near far conditions.

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SIR-optimized weighted linear parallel interference canceller on fading channels

Cited by 12 publications

References 7 publications

A Distributed Approach to Interference Cancellation

A Distributed Approach to Interference Cancellation

Improved Linear Parallel Interference Cancellers

Robust blind PIC with adaptive despreader and improved interference estimator

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