Capacity improvement with a multihop access scheme in broadband CDMA cellular systems

Abstract

SUMMARYThe use of multihop connection, in which a station in between the mobile station and the base station performs hopping relay of the transmission, in CDMA cellular systems should expand the area coverage and reduce the transmitted power per hop. There is a possibility that interference power may be reduced and that system capacity may be enlarged by this approach. Depending on the method of application, however, the system capacity may be decreased due to the interference during hopping. In this study, a basic investigation of interference reduction by multihop connection is first presented. Then, a procedure for selection of the hop stations with a strong capability for reducing the interference power is proposed. Considering a multicellular environment with a CDMA (code division multiple access) cellular scheme, the characteristics of multihop connections are evaluated by computer simulation, assuming packet access. It is shown that multihop connection has the effect of improving system capacity.

Theoretical evaluation of spectral efficiency and outage probability of TDMA multihop cellular systems

“…The probability density function of the sum of lognormalized random numbers can be approximated by a single lognormal distribution [13]. Therefore, the probability density function f d 1 ,...,d 6 As shown in Eqs. (3) and (5), both probability density functions of the local mean received signal power x and the local mean received interference power y are lognormal distributions.…”

“…(3) and (5), both probability density functions of the local mean received signal power x and the local mean received interference power y are lognormal distributions. Therefore, the probability density function h d,d 1 ,...,d 6 (γ) of the local mean received CIR γ is given by the following lognormal distribution:…”

Transmit Power Efficiency of Multi-Hop MRC Diversity for a Virtual Cellular Network

“…The routing algorithm is an important technical issue to select the relaying intermediate ports till the central port. Routing algorithms proposed for wireless multi-hop network or adhoc network [3]- [6] can be applied to VCN. To increase the frequency efficiency, a routing algorithm that minimizes the total uplink transmit power while limiting the number of hops was introduced [7].…”

Transmit power efficiency of multi-hop hybrid selection/MRC diversity for a DS-CDMA virtual cellular network

“…Unlike the so-called wireless ad-hoc network [2]- [5], each stationary wireless port relays the signal to the next port. For uplink (downlink) data transmissions, many wireless ports can be used to relay the signal transmitted from a mobile terminal (the central port) to the central port (a mobile terminal).…”

“…Routing algorithm is an important technical issue. Various routing algorithms have been proposed for wireless multi-hop network or ad-hoc network [2]- [5]. They can be applied to the VCN.…”