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Design of simplified maximum-likelihood receivers for multiuser CPM systems.

Bing L, Bai B - ScientificWorldJournal (2014)

Bottom Line: The performance of the proposed receivers is analyzed and compared to some existing receivers.Some schemes are designed to implement the proposed receivers and to reveal the roles of different system parameters.Analysis and numerical results show that the proposed receivers can approach the optimum multiuser receivers with significantly (even exponentially in some cases) reduced complexity and marginal performance degradation.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of ISN, Xidian University, Xi'an 710071, China.

ABSTRACT
A class of simplified maximum-likelihood receivers designed for continuous phase modulation based multiuser systems is proposed. The presented receiver is built upon a front end employing mismatched filters and a maximum-likelihood detector defined in a low-dimensional signal space. The performance of the proposed receivers is analyzed and compared to some existing receivers. Some schemes are designed to implement the proposed receivers and to reveal the roles of different system parameters. Analysis and numerical results show that the proposed receivers can approach the optimum multiuser receivers with significantly (even exponentially in some cases) reduced complexity and marginal performance degradation.

No MeSH data available.


System model.
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Related In: Results  -  Collection


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fig1: System model.

Mentions: A multiple-access-channel (MAC) type multiuser CPM system consisting of K users is shown in Figure 1. It is assumed that all users employ an identical CPM scheme, where the modulation parameters such as the transmitted energy E, modulation level M, modulation index h, and phase response q(t) are the same. The kth (1 ≤ k ≤ K) user maps its information sequence ak = {ak1, ak2,…, akN} independently to the transmitted signal, whose equivalent complex baseband signal reads [1](1)sk(t,ak)=2ETexp⁡⁡j{φ(t,ak)+2πfkt+ϕk},where T, E, and q(t) are the symbol duration, signal energy and phase response, respectively. The information-bearing phase is(2)φ(t,ak)={2πh∑iakiq(t−iT)},where h = k/p is the modulation index and the transmitted symbol aki ∈ {±1, ±3,…, ±(M − 1)}. The phase response function q(t) is defined as(3)q(t)=∫−∞tg(τ)dτ,where g(τ) is the frequency response assumed to be causal and of duration L symbols. The phase response has the following property:(4)q(t)={12t≥LT0t<0.The frequency separation fk and phase separation ϕk are(5)fk=Δf(k−K+12),ϕk=Δϕ(k−K+12),where Δf and Δϕ are frequency spacing and phase spacing [6], respectively. According to the model, the superimposed signal (or the equivalent MAC signal) reads(6)s(t,a)=∑k=1k=Ksk(t,ak).


Design of simplified maximum-likelihood receivers for multiuser CPM systems.

Bing L, Bai B - ScientificWorldJournal (2014)

System model.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3927751&req=5

fig1: System model.
Mentions: A multiple-access-channel (MAC) type multiuser CPM system consisting of K users is shown in Figure 1. It is assumed that all users employ an identical CPM scheme, where the modulation parameters such as the transmitted energy E, modulation level M, modulation index h, and phase response q(t) are the same. The kth (1 ≤ k ≤ K) user maps its information sequence ak = {ak1, ak2,…, akN} independently to the transmitted signal, whose equivalent complex baseband signal reads [1](1)sk(t,ak)=2ETexp⁡⁡j{φ(t,ak)+2πfkt+ϕk},where T, E, and q(t) are the symbol duration, signal energy and phase response, respectively. The information-bearing phase is(2)φ(t,ak)={2πh∑iakiq(t−iT)},where h = k/p is the modulation index and the transmitted symbol aki ∈ {±1, ±3,…, ±(M − 1)}. The phase response function q(t) is defined as(3)q(t)=∫−∞tg(τ)dτ,where g(τ) is the frequency response assumed to be causal and of duration L symbols. The phase response has the following property:(4)q(t)={12t≥LT0t<0.The frequency separation fk and phase separation ϕk are(5)fk=Δf(k−K+12),ϕk=Δϕ(k−K+12),where Δf and Δϕ are frequency spacing and phase spacing [6], respectively. According to the model, the superimposed signal (or the equivalent MAC signal) reads(6)s(t,a)=∑k=1k=Ksk(t,ak).

Bottom Line: The performance of the proposed receivers is analyzed and compared to some existing receivers.Some schemes are designed to implement the proposed receivers and to reveal the roles of different system parameters.Analysis and numerical results show that the proposed receivers can approach the optimum multiuser receivers with significantly (even exponentially in some cases) reduced complexity and marginal performance degradation.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of ISN, Xidian University, Xi'an 710071, China.

ABSTRACT
A class of simplified maximum-likelihood receivers designed for continuous phase modulation based multiuser systems is proposed. The presented receiver is built upon a front end employing mismatched filters and a maximum-likelihood detector defined in a low-dimensional signal space. The performance of the proposed receivers is analyzed and compared to some existing receivers. Some schemes are designed to implement the proposed receivers and to reveal the roles of different system parameters. Analysis and numerical results show that the proposed receivers can approach the optimum multiuser receivers with significantly (even exponentially in some cases) reduced complexity and marginal performance degradation.

No MeSH data available.