# Optimum asymptotic multiuser efficiency of randomly spread CDMA

@article{Tse2000OptimumAM, title={Optimum asymptotic multiuser efficiency of randomly spread CDMA}, author={David Tse and Sergio Verd{\'u}}, journal={IEEE Trans. Inf. Theory}, year={2000}, volume={46}, pages={2718-2722} }

This correspondence analyzes the high signal-to-noise ratio (SNR) performance of optimum multiuser detectors for synchronous direct-sequence spread spectrum with random spreading in an additive white Gaussian noise channel. Under very general conditions on the received powers, we show that the optimum asymptotic efficiency of a K-user system with spreading gain N converges to 1 almost surely as K/spl rarr//spl infin/, and K/N is kept equal to an arbitrary nonzero constant. Therefore, the…

## 59 Citations

### Optimum Asymptotic Multiuser Efficiency of Pseudo-Orthogonal Randomly Spread CDMA

- Computer ScienceArXiv
- 2006

The high signal-to-noise ratio performance of the PO-CDMA is analyzed by rigorously deriving its asymptotic multiuser efficiency (AME) in the large system limit.

### Asymptotic bounds on the Optimum Multiuser Efficiency of randomly spread CDMA

- Computer Science2014 12th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)
- 2014

We derive some bounds on the Optimum Asymptotic Multiuser Efficiency (OAME) of randomly spread CDMA as extensions of the result by Tse and Verdú. To this end, random Gaussian and random binary…

### On Optimum Asymptotic Multiuser Efficiency of Randomly Spread CDMA

- Computer ScienceIEEE Transactions on Information Theory
- 2015

It is shown that the optimum detector in a Gaussian randomly spread CDMA system has a performance close to the single user system at high signal-to-noise ratio when K and N → ∞ and the loading factor, (K/N), is kept less than (log3 K/2).

### A family of likelihood ascent search multiuser detectors: approaching optimum performance via random multicodes with linear complexity

- Computer ScienceIEEE Transactions on Communications
- 2009

It is shown that the wide-sense sequential likelihood ascent search (WSLAS) detectors achieve unit AME with channel load < 1/2 - 1/(4 ln 2) bits/s/Hz and in simulations for random multicode equal-power systems, the WSLAS with a linear per-bit complexity approaches the GML BER in all SNR.

### Tight Bounds on the Capacity of Binary Input Random CDMA Systems

- Computer ScienceIEEE Transactions on Information Theory
- 2010

An upper bound to the capacity of code-division multiple-access communication over a binary input additive white Gaussian noise channel is proved using random spreading and concentration of various relevant quantities is shown.

### A Family of Likelihood Ascent Search Multiuser Detectors: Approach to Single-User Performance via Quasi-Large Random Sequence CDMA

- Computer ScienceArXiv
- 2007

It is obtained that the WSLAS detector with a linear per-bit complexity achieves unit AME in the LRS-CDMA with a channel load < ½ − 1/(4ln2) bits/s/Hz.

### A statistical-mechanics approach to large-system analysis of CDMA multiuser detectors

- Computer ScienceIEEE Trans. Inf. Theory
- 2002

The performance of uncoded, fully synchronous, randomly spread code-division multiple-access (CDMA) multiuser detectors with additive white Gaussian noise (AWGN) channel, under perfect power control, and in the large-system limit is evaluated.

### Approach to Optimum Performance in Random Spreading CDMA by Linear-Complex LAS Detectors

- Mathematics2007 41st Annual Conference on Information Sciences and Systems
- 2007

A BER upper bound is applied to analyze the performance of local maximum likelihood (LML) detectors in large random spreading CDMA (LRS-CDMA) channels where user number A' and spreading gain N tend to infinity and KIN keeps a constant.

### Iterative multiuser joint decoding: optimal power allocation and low-complexity implementation

- Computer ScienceIEEE Transactions on Information Theory
- 2004

This work optimize the received user signal-to-noise ratio (SNR) distribution in order to maximize the system spectral efficiency for given user channel codes, channel load, and target user bit-error rate.

### Large-System Analysis of Static Multiuser Detection with an Unknown Number of Users

- Computer Science, Physics2007 2nd IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing
- 2007

A study of large multiple-access communication systems in which multiuser detection is performed without knowledge of the number of interferers and the replica method is used as a key technique to compute the free-energy function and the macroscopic parameters that determine the multiusers efficiency and the bit error probability in the large system limit.

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